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	<title>为IT服务 [龙飞的博客]</title>
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	<description>什么都略懂一点，生活就多彩一些</description>
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		<title>child pid XXXX exit signal Segmentation fault (11)的一个解决办法</title>
		<link>http://226617.cn/archives/959.htm</link>
		<comments>http://226617.cn/archives/959.htm#comments</comments>
		<pubDate>Sun, 08 Jan 2012 15:58:02 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[php相关]]></category>
		<category><![CDATA[apache]]></category>
		<category><![CDATA[php]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=959</guid>
		<description><![CDATA[最近在测试一个虚拟主机管理软件LuManager2.0，用的centos6 64位的系统装完进入管理界面 始终出错 firefox打开页面一片空白，看apache的日志是 child pid XXXX exit signal Segmentation fault (11) 手工传个phpinfo... ]]></description>
			<content:encoded><![CDATA[<p>最近在测试一个虚拟主机管理软件LuManager2.0，用的centos6 64位的系统装完进入管理界面 始终出错 firefox打开页面一片空白，看apache的日志是</p>
<p>child pid XXXX exit signal Segmentation fault (11)</p>
<p>手工传个phpinfo进去倒是可以执行的，这个错误造成的原因很多，多半是和内存啊模块之类的有关，仔细看了看apache和php的配置，发现php里面启用了eaccelerator ，关掉重启apache后解决了。</p>
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		<title>VMware ESX/ESXi 使用NETAPP存储 FCP Partner Path Misconfigured 报错处理</title>
		<link>http://226617.cn/archives/952.htm</link>
		<comments>http://226617.cn/archives/952.htm#comments</comments>
		<pubDate>Thu, 27 Oct 2011 08:57:35 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[只谈技术]]></category>
		<category><![CDATA[硬件相关]]></category>
		<category><![CDATA[esx4.1]]></category>
		<category><![CDATA[fcp]]></category>
		<category><![CDATA[lun]]></category>
		<category><![CDATA[netapp]]></category>
		<category><![CDATA[vmware]]></category>
		<category><![CDATA[光纤存储]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=952</guid>
		<description><![CDATA[VMware ESX/ESXi 使用NETAPP存储 FCP Partner Path Misconfigured 报错处理 在VMware ESX/ESXi 使用NETAPP存储时，存在多路径访问存储lun的情况下如果配置不当极易引起报错： [hostname: scsitarget.partnerPath.misconfigured:er... ]]></description>
			<content:encoded><![CDATA[<p>VMware ESX/ESXi 使用NETAPP存储 FCP Partner Path Misconfigured 报错处理</p>
<p>在VMware ESX/ESXi 使用NETAPP存储时，存在多路径访问存储lun的情况下如果配置不当极易引起报错：<br />
<code>[hostname: scsitarget.partnerPath.misconfigured:error]: FCP Partner Path Misconfigured - Host I/O access through a non-primary and non-optimal path was detected.<br />
</code><br />
这个主要是因为ESX主机在访问lun时使用了非主路径造成的，就如下图这种情况：<br />
<img class="alignnone size-full wp-image-955" title="kb30541" src="http://226617.cn/wp-content/uploads/2011/10/kb30541.gif" alt="" width="629" height="523" /></p>
<p>从上图来看我们可以看到这个lun在主机上实际是有2个访问路径的，一个是通过lun所在的机头访问的主路径，另一个是Partner机头的备用路径。<br />
如果是更加高可用的采用2个机头各自使用2个光纤交叉连接至2个交换机的方式，那么每个lun在主机上对应的访问路径将会有4个，其中2个是主路径，2个是备用路径。</p>
<p>那么在ESX中是如何来选择多路径的呢，这里也介绍下ESX的多路径选择机制。<br />
首先ESX会判断存储的类型，主要是A/P主-被、A/A主-主、ALUA主-被和非对称主-主这几种。<br />
对应不同的存储类型ESX会使用不同的默认路径选择方式：</p>
<p>最近使用(VMW_PSP_MRU)：选择最近用于访问指定设备的路径。如果此路径不可用，则会切换到替代路径并在该新路径可用时继续使用它。MRU是主-被阵列（A/P- Active/Passive）的默认路径策略。<br />
固定(VMW_PSP_FIXED)：使用指定首选路径（如果已配置）。否则，它将使用在系统引导时间发现的第一个工作路径。如果主机不能使用首选路径，则它会选择随机替代可用路径。一旦首选路径可用，主机便会恢复到首选路径。“固定”是主-主阵列（A/A &#8211; Symmetric Active/Acivie）的默认路径策略。<br />
VMW_PSP_FIXED_AP：将“固定”功能扩展到主动-被动阵列和非对称主-主（ALUA &#8211; Asymmetric Active/Active）阵列。<br />
循环(VMW_PSP_RR) ：使用路径选择算法轮流选择所有可用的活动路径，并在路径之间启用负载平衡。</p>
<p>根据我管理的系统中2台NETAPP的存储在ESX中均被识别为：VMW_SATP_DEFAULT_AA，就是A/A主-主类型，所以他默认使用的是 固定(VMW_PSP_FIXED)。<br />
那么问题就在这里了，由于固定(VMW_PSP_FIXED)方式的路径选择，ESX将会选用第一个发现的路径作为首选路径来使用，但是有些时候这往往不是主路径，所以就导致了Host I/O access through a non-primary and non-optimal path was detected.的报错。<br />
这个时候就需要手工调整首选路径了，那么如何来确定什么路径才是主路径呢？</p>
<p>1.首选确定目标lun所在的机头<br />
这个我想不用多说了</p>
<p>2.连上目标lun所在的机头确认FC Nodename和Portname</p>
<p><code>FAS2050A&gt; fcp show adapters<br />
Slot: 0a<br />
Description: Fibre Channel Target Adapter 0a (Dual-channel, QLogic 2432 (2462) rev. 2)<br />
Adapter Type: Local<br />
Status: ONLINE<br />
FC Nodename: 50:0a:09:80:88:8c:82:35 (500a0980888c8235)<br />
FC Portname: 50:0a:09:81:88:8c:82:35 (500a0981888c8235)<br />
Standby: No</code></p>
<p>Slot: 0b<br />
Description: Fibre Channel Target Adapter 0b (Dual-channel, QLogic 2432 (2462) rev. 2)<br />
Adapter Type: Local<br />
Status: ONLINE<br />
FC Nodename: 50:0a:09:80:88:8c:82:35 (500a0980888c8235)<br />
FC Portname: 50:0a:09:82:88:8c:82:35 (500a0982888c8235)<br />
Standby: No</p>
<p>根据上例返回的信息，这个机头有2个hba卡，在esx看到的目标路径就是Nodename Portname，这个的2个目标路径就是<br />
<code>50:0a:09:80:88:8c:82:35 50:0a:09:81:88:8c:82:35<br />
50:0a:09:80:88:8c:82:35 50:0a:09:82:88:8c:82:35<br />
</code><br />
3.知道了目标路径后打开esx存储适配器手工指定目标lun的首选路径</p>
<p><img class="alignnone size-full wp-image-954" title="7" src="http://226617.cn/wp-content/uploads/2011/10/7.jpg" alt="" width="582" height="421" /><br />
本图由于有4个路径分表是其中有2个目标路径对应lun所在机头的2个hba卡，可以根据实际情况手工指定不同的hba卡分流流量。</p>
<p>如何检测调整的效果<br />
1. lun stats -o 查看Partner Ops 和 Partner KBytes 字段，可以直观的以lun列表的形式查看，如果是调整后可以使用lun stats -z清空统计数据。<br />
2. sysstat -b 1 查看Partner字段，可以直观的以实时监控的形式查看。</p>
<p>如果上述字段为非0那就说明有Host I/O access through a non-primary and non-optimal path的情况。</p>
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		<item>
		<title>cisco stp相关配置</title>
		<link>http://226617.cn/archives/942.htm</link>
		<comments>http://226617.cn/archives/942.htm#comments</comments>
		<pubDate>Thu, 27 Oct 2011 07:13:22 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[硬件相关]]></category>
		<category><![CDATA[cisco]]></category>
		<category><![CDATA[h3c]]></category>
		<category><![CDATA[spanning-tree]]></category>
		<category><![CDATA[stp]]></category>
		<category><![CDATA[交换机]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=942</guid>
		<description><![CDATA[这里不去介绍相关知识了，网上一搜一大堆。写这篇博客只是为了记录下解决我单位混乱二层网络管理无从下手的一些心得。 交换机配置一向不是我的强项，这次调整stp完全出于无奈，我们单... ]]></description>
			<content:encoded><![CDATA[<p>这里不去介绍相关知识了，网上一搜一大堆。写这篇博客只是为了记录下解决我单位混乱二层网络管理无从下手的一些心得。<br />
交换机配置一向不是我的强项，这次调整stp完全出于无奈，我们单位的网络期初是从1台借用的二层交换机开始的，逐步的添加扩展直到今天位于3个机房、13台交换机的规模、9个网段，由于我懒，加上随意配ip习惯，导致了这种局面，要起三层必须等于是要把网络这层全部铲了从起炉灶，伤不起啊，前车之鉴啊，各位规划网络初期就一定要注意啊！</p>
<p>我们这个大二层从划分来讲主要就是3大块，1,中心机房 2,电信机房 3,办公室。<br />
故事(事故)是这样开始的，由于单位搬了新大楼，而新大楼的网络全部使用的是h3c产品，我们在14楼使用的是我们单位独立的网络，但是平时也有其他一些楼层需要用我们的网段跑些业务，所以在14楼我们在我们网络的cisco交换机与大楼本身网络的h3c交换机之间做了互通并在大楼网络里面起了个我们的vlan，这样就能利用大楼的网络方便的将某些端口划到分到我们的vlan里面就能使用我们的出口和网络了。但是问题出现了，在楼道里cisco和h3c互联接线的那刻，大楼网络从楼道的h3c交换机开始一直瘫倒核心。后来把我们楼道里面那台cisco的stp关了才算了事。cisco的stp是只能针对vlan关的，像我们那种傻瓜用法的等于要关掉整个交换机的stp，这很不爽。调整双方stp协议对接也很不现实，大楼网络不会为了我们一个小网络去做调整。所以我只能想其他办法了。</p>
<p>网上看了几天资料了解了，看完才知道，原来二层网络也是需要管理维护的。</p>
<p><strong>1.根桥(root bridge)</strong><br />
二层网络首先要确定一个根桥(root bridge)，虽然什么都不配交换机之间也能自己协商出来一个，但是有些情况下那往往不是你所希望的，而且随着后期交换机的加入还会发生变化。<br />
如何确定根桥(root bridge)：</p>
<p><code>3750#show spanning-tree</code></p>
<pre>VLAN0010
  Spanning tree enabled protocol ieee
  Root ID    Priority    24577
             Address     04c5.a488.c400
             Cost        4
             <span style="text-decoration: underline;"><span style="color: #ff0000; text-decoration: underline;">Port 3 (GigabitEthernet1/0/3)</span></span>
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec

  Bridge ID  Priority    32778  (priority 32768 sys-id-ext 10)
             Address     04c5.a488.c400
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec
             Aging Time 300

Interface        Role Sts Cost      Prio.Nbr Type
---------------- ---- --- --------- -------- --------------------------------
Gi1/0/3          Root FWD 4         128.3    P2p
Gi1/0/4          Desg FWD 19        128.4    P2p</pre>
<p>沿着这个返回端口在途径的交换机上面重复 show spanning-tree 直到出现</p>
<pre>VLAN0001
  Spanning tree enabled protocol ieee
  Root ID    Priority    24577
             Address     04c5.a488.c400
             <span style="text-decoration: underline;"><span style="color: #ff0000; text-decoration: underline;">This bridge is the root</span></span>
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec

  Bridge ID  Priority    24577  (priority 24576 sys-id-ext 1)
             Address     04c5.a488.c400
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec
             Aging Time 300</pre>
<p>这就是你二层网络的 根桥(root bridge)。</p>
<p><strong>2.如何手工指定根桥(root bridge)</strong><br />
<code>3750#conf t<br />
3750(config)#spanning-tree vlan 1 root primary</code></p>
<p><strong>3.根保护(Root Guard)<br />
</strong>根保护(Root Guard)的作用是防止指定端口下级网络环境中出现根桥(root bridge)，虽然你通过手工可以指定根桥(root bridge)但是他的优先级(Priority)是固定为24577的(数值越低优先级越高)，一旦下级网络中有手工指定的优先级更高的交换机出现那么它就会占据根桥(root bridge)。这时候就需要配置根保护(Root Guard)防止这种情况。<br />
<code>3750#conf t<br />
3750(config)#interface gigabitEthernet1/0/26<br />
3750(config-if)#spanning-tree bpduguard enable<br />
</code><br />
端口配置了根保护(Root Guard)后，一旦接收到优先级比现有根更高的BPDU包这个端口就会被转为Block状态，直到不再接受到BPDU包或者优先级高的BPDU包。<br />
<strong></strong></p>
<p><strong>3.BPDU过滤(BPDU Filtering)<br />
</strong>BPDU过滤(BPDU Filtering)顾名思义，过滤BPDU。端口接受到任何的BPDU包一律到此为止，不在往端口上转发。一般配合PortFast用于连接主机的端口。<br />
<code>3750#conf t<br />
3750(config)#interface gigabitEthernet1/0/26<br />
3750(config-if)#spanning-tree bpdufilter enable<br />
</code><br />
一旦端口启用BPDU过滤(BPDU Filtering)要注意不能出现环路，不然就真的瘫了。而且BPDU过滤(BPDU Filtering)优先级比根保护(Root Guard)高所以同时启用2个功能的话根保护(Root Guard)是不起作用的。</p>
<p>至于上面我单位遇到的问题，我测试了一下在手工指定根桥(root bridge)后再在14楼cisco上于h3c互联的端口启用BPDU过滤(BPDU Filtering)，同时关闭h3c相应端口的stp后在打开cisco交换机的stp，网络就正常了。</p>
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		<title>centos6下挂载nfs</title>
		<link>http://226617.cn/archives/937.htm</link>
		<comments>http://226617.cn/archives/937.htm#comments</comments>
		<pubDate>Fri, 07 Oct 2011 12:17:25 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[linux相关]]></category>
		<category><![CDATA[只谈技术]]></category>
		<category><![CDATA[centos]]></category>
		<category><![CDATA[linux]]></category>
		<category><![CDATA[nfs]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=937</guid>
		<description><![CDATA[其实和以前的centos5没啥区别，只不过centos的安装是选mini的还真够mini的，啥都要自己yum。这不连nfs都默认不装了。 mount -t nfs 192.168.1.1:/nfs1 /mnt/nfs 直接提示 mount: wrong fs type, bad option, bad superblock o... ]]></description>
			<content:encoded><![CDATA[<p>其实和以前的centos5没啥区别，只不过centos的安装是选mini的还真够mini的，啥都要自己yum。这不连nfs都默认不装了。<br />
mount -t nfs 192.168.1.1:/nfs1 /mnt/nfs<br />
直接提示</p>
<pre>mount: wrong fs type, bad option, bad superblock on 192.168.1.1:/nfs1,
       missing codepage or helper program, or other error
       (for several filesystems (e.g. nfs, cifs) you might
       need a /sbin/mount.&lt;type&gt; helper program)
       In some cases useful info is found in syslog - try
       dmesg | tail  or so</pre>
<p>需要安装下相关的软件包<br />
yum -y install nfs-utils nfs-utils-lib</p>
<p>这时再尝试依然会出错</p>
<pre>mount.nfs: rpc.statd is not running but is required for remote locking.
mount.nfs: Either use '-o nolock' to keep locks local, or start statd.
mount.nfs: an incorrect mount option was specified</pre>
<p>原因是rpcbind没启动<br />
chkconfig &#8211;list看见是默认启动的，应该是刚装后没启动，手工启动下。<br />
/etc/rc.d/init.d/rpcbind start<br />
然后再<br />
mount -t nfs 192.168.1.1:/nfs1 /mnt/nfs 就正常了</p>
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		<title>关闭centos6的ipv6</title>
		<link>http://226617.cn/archives/934.htm</link>
		<comments>http://226617.cn/archives/934.htm#comments</comments>
		<pubDate>Fri, 07 Oct 2011 08:00:47 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[linux相关]]></category>
		<category><![CDATA[centos]]></category>
		<category><![CDATA[ipv6]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=934</guid>
		<description><![CDATA[新增文件 /etc/modprobe.d/ipv6-off.conf  内容： alias net-pf-10 off alias ipv6 off 编辑 /etc/sysconfig/network 增加内容： NETWORKING_IPV6=no 关闭自动启动ip6tables chkconfig ip6tables off 重启即... ]]></description>
			<content:encoded><![CDATA[<p>新增文件 <strong>/etc/modprobe.d/ipv6-off.conf</strong>  内容：</p>
<div>
<pre>alias net-pf-10 off
alias ipv6 off</pre>
</div>
<p>编辑 <strong>/etc/sysconfig/network</strong> 增加内容：</p>
<div>
<pre>NETWORKING_IPV6=no</pre>
</div>
<p>关闭自动启动ip6tables</p>
<p><span class="Apple-style-span" style="font-family: Consolas, Monaco, monospace; font-size: 12px; line-height: 18px; white-space: pre;">chkconfig ip6tables off</span><br />
重启即可</p>
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		<title>克隆centos6虚拟机后网络无法启动问题解决</title>
		<link>http://226617.cn/archives/929.htm</link>
		<comments>http://226617.cn/archives/929.htm#comments</comments>
		<pubDate>Fri, 07 Oct 2011 05:57:24 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[linux相关]]></category>
		<category><![CDATA[只谈技术]]></category>
		<category><![CDATA[centos]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=929</guid>
		<description><![CDATA[在克隆centos6的虚拟机后会发现启动网络的时候有报错 Bringing up interface eth0:  Device eth0 does not seem to be present, delaying initialization. 查看配置文件发现并没有像centos5那样克隆后会把原先的ifcfg-eth0备... ]]></description>
			<content:encoded><![CDATA[<p>在克隆centos6的虚拟机后会发现启动网络的时候有报错</p>
<p>Bringing up interface eth0:  Device eth0 does not seem to be present, delaying initialization.</p>
<p>查看配置文件发现并没有像centos5那样克隆后会把原先的ifcfg-eth0备份成ifcfg-eth0.bak然后生成新的初始化的ifcfg-eth0</p>
<p>上网查了查资料，原来centos6会对mac地址和网卡设备名进行绑定，克隆前网卡的mac地址已经绑定了eth0，在克隆后生成的新的mac地址被顺延绑定到了eth1，但是我们又没有对应eth1</p>
<p>的配置文件所以启动就提示出错了。</p>
<p>只需要编辑</p>
<p>vi /etc/udev/rules.d/70-persistent-net.rules</p>
<p>将原来eth0那行删除，把新生成的eth1那行里面的eth1改成eth0 然后修改或者删除下配置文件里面的mac地址和uuid和最后重启下即可。</p>
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		<item>
		<title>Varnish 3.0的vcl处理流程图</title>
		<link>http://226617.cn/archives/915.htm</link>
		<comments>http://226617.cn/archives/915.htm#comments</comments>
		<pubDate>Tue, 27 Sep 2011 01:16:47 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[只谈技术]]></category>
		<category><![CDATA[软件相关]]></category>
		<category><![CDATA[varnish]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=915</guid>
		<description><![CDATA[最近在尝试的用varnish，资料太少，偶然看见一个vcl的处理流程图，哪来分享下 另外可以安装个  GraphViz 用以下命令可以导出你所用版本的 ### for postscript output $ sed -n &#8216;/^DOT/s///p&#8217; varnish-... ]]></description>
			<content:encoded><![CDATA[<p>最近在尝试的用varnish，资料太少，偶然看见一个vcl的处理流程图，哪来分享下</p>
<div>另外可以安装个 <a href="http://www.graphviz.org/"> GraphViz</a> 用以下命令可以导出你所用版本的</div>
<blockquote>
<div>### for postscript output</div>
<div>$ sed -n &#8216;/^DOT/s///p&#8217; varnish-cache/bin/varnishd/cache_center.c | dot -Tps &gt; /tmp/varnish-flow.ps</div>
<div>### for pdf output</div>
<div>$ sed -n &#8216;/^DOT/s///p&#8217; varnish-cache/bin/varnishd/cache_center.c | dot -Tpdf &gt; /tmp/varnish-flow.pdf</div>
</blockquote>
<p><a class="highslide-image" onclick="return hs.expand(this, {captionId:'caption_1317086528919'});" href="http://226617.cn/wp-content/uploads/2011/09/varnish-flow.png"><img title="Click to enlarge" src="http://226617.cn/wp-content/uploads/2011/09/varnish-flow-506x1024.png" alt="image" /></a></p>
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		<item>
		<title>总结一些netapp管理中的误区把，省的初学者绕弯路。</title>
		<link>http://226617.cn/archives/910.htm</link>
		<comments>http://226617.cn/archives/910.htm#comments</comments>
		<pubDate>Tue, 13 Sep 2011 03:47:33 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[硬件相关]]></category>
		<category><![CDATA[netapp]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=910</guid>
		<description><![CDATA[1.建立lun的时候lun name最好就直接写明白lun的内容。 我之前是这样建lun的 lun create -s 201g -t linux -o noreserve /vol/volb1/web1/lun1 lun comment /vol/volb1/web1/lun1 web1 本来想想这样子已经够清楚了，没想到最近... ]]></description>
			<content:encoded><![CDATA[<p>1.建立lun的时候lun name最好就直接写明白lun的内容。</p>
<p>我之前是这样建lun的</p>
<p>lun create -s 201g -t linux -o noreserve /vol/volb1/web1/lun1<br />
lun comment /vol/volb1/web1/lun1 web1</p>
<p>本来想想这样子已经够清楚了，没想到最近在用lun_top监控lun的读写情况是发现他就仅仅用了lun name，而不是path。结果就是重头到尾的排序都是lun1<br />
解决方法：lun move /vol/volb1/web1/lun1 /vol/volb1/web1/lun.web1</p>
<p>未完待整理</p>
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		</item>
		<item>
		<title>我们需要做什么怎么做&#8211;写在网络电视平台升级前</title>
		<link>http://226617.cn/archives/902.htm</link>
		<comments>http://226617.cn/archives/902.htm#comments</comments>
		<pubDate>Mon, 12 Sep 2011 15:55:51 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[只谈心情]]></category>
		<category><![CDATA[三屏合一]]></category>
		<category><![CDATA[三网融合]]></category>
		<category><![CDATA[网络电视]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=902</guid>
		<description><![CDATA[网络电视台，这一新鲜名词自从中国网络电视台上线开播的那一天起而出名。10年初那会全国各省市县台，仿佛一夜之间都忽然醒悟般的纷纷开始建设或准备建设各种形式的网络电视台。就连我... ]]></description>
			<content:encoded><![CDATA[<p>网络电视台，这一新鲜名词自从中国网络电视台上线开播的那一天起而出名。10年初那会全国各省市县台，仿佛一夜之间都忽然醒悟般的纷纷开始建设或准备建设各种形式的网络电视台。就连我们无锡广电也不可避免的修改了一版新的界面，套着05-06年间的底层平台堂而皇之的成立了无锡网络广播电视台，而后又因为总局下令不准叫台而改成了无锡网络广播电视。</p>
<p>时至今日，无锡网络广播电视终于不堪现状，在彻底的落后系统平台折磨下走上了升级之路，我们在这次升级前主要评判了老系统的几个致命缺点：<br />
1.无法跨平台跨浏览器播放<br />
2.无移动终端平台解决方案<br />
3.自动录播无法精确录制节目的开始和结束时间点（这归功于坑爹的播出时间准确性）<br />
4.虚拟标注无法满足现状需求，及无法清理过期整档节目，无法单独删除某条标注新闻内容（彻底消失的那种，你懂得）。<br />
5.系统平台本地可维护性太低，出了问题基本只能找厂商解决。</p>
<p>同时我们也在想我们需要把我们无锡网络广播电视台做成什么个样子。我们需要什么？</p>
<p>自从我们有了升级整个平台那个想法开始这个问题就一直纠结在我的心头。虽然我只是从技术的角度去看待这个问题，但这并不能代表写个1234就能有明确答案的。当然刚开始我也曾这样写了几个答案，无非就是要针对的解决上面那12345的缺点。但是我知道这并不是我想要的答案。</p>
<p>俗话说当局者迷旁观者清，没想到我也迷糊了进去。从大的角度来讲，这么多的省台市台县台花大力气大资金去建设网络电视台为的是什么，中国人式的一窝蜂很好的给出了答案，当然我们也看到了其中的一些领跑者佼佼者。于是我们决定走出去看一看、学一学。果真站在旁观者的角度看了几家之后，我领悟了。这里要非常感谢济南台网络公司关于三网融合三屏续看和linux机顶盒的启发。那就是我们要走创新，我们要自己开发基于网台的应用，我们要继续领跑地方网台的下一个5年。</p>
<p>三网融合、三屏合一这2词近几年没少出现过，虽然我从未去参加BRTV等这类相关的展会，但是我也清楚国内有很多的厂商都在这2词上面下功夫。电视机从有线电视开始到现在的数字电视，用户的收看方式几乎就没变过，虽然高清电视的出现可以让大家眼前一亮，但是这保鲜期一过本质上还是那个老样子，很难想象这样的收看方式能吸引80后90后这一5至10年后的主流高端用户。相比而且我更加看好电信的itv，至少再看itv的时候还会让用户觉得有点自主权，但是反观内容分类形式除了直播外那些点播内容这那一个视频网站上没有，唯一的好处就是在电视前动动遥控器就能看而已，还就稍微清楚了一点。</p>
<p>在去济南台之前我从来就没想过我们的网络电视平台要在电视播出，因为那是我认为我们来做一个能够通过机顶盒能够在电视上看的网台成本太大，缺乏相关技术知识，后续相关开发可定制性太差。（这都拜数字电视机顶盒那坑爹的浏览器所赐）之前我们也为数字电视的机顶盒浏览器做过相关的开发，那调效果简直自杀的心都有，最后做出来的东西不光巨丑无比，也让我们从此对机顶盒产生了敬畏之心。好吧我承认我有井底之蛙了一会，在济南台看到的那个浪潮linux机顶盒+chrome核心浏览器让我眼前一亮。chrome核心浏览器这意味着啥，这等于做好网页开发我们就能进行电视机的交互界面啊，做网页开发不正是我们的强项么。正因为这个重大的发现（这确实有点汗颜，看来以后有机会也要去BRTV等这类展会多看看）加上济南台网络公司演示三屏断点续看一下子把我的思想打开了，我瞬间重新定位了无锡网台的技术方向：三屏、创新、演示。</p>
<p>在济南台参观学习之后去了趟泰山，站在玉皇顶一览众山，我当时也决定了与其跟着别人走，不如我们自己冲在前面，只要寻找到有实力的合作伙伴，我们完全能做到在三网融合、三屏合一上的创新。</p>
<p>一直以来我都相信当前的年轻人或者平时上网人群，为什么他们不愿意或者很少看电视？不是因为电视的内容有多落后有多差，而是因为观看方式模式赶跑了他们。三网融合不是把三张网用一张网来代替，用电视机来上网或者用电脑来看电视。三屏合一也不仅仅是把同一个视频让他能在电视，电脑和手机屏幕上能同时观看而已。我所认为的三网融合应该是将三张网的优势各自互补，将电脑的可交互性与电视机的可观看性结合，我想看什么用电脑去完成，我怎么看用电视去完成诸如此类。</p>
<p>简单描述这么一个场景：<br />
白天上班我在论坛看帖子获知了今天某某路发生了一起事故，随后系统获知了我对此事件的关注，在相关传统媒体进行报道的同时进行了汇总，当我在回家路上时通过手机通知了我相关的媒体报道情况，我简单的浏览了相关报道。晚饭后坐在沙发上，我打开电视机，系统根据我在手机端浏览的情况自动提醒我某台新闻栏目10分钟前对此事的相关报道，我选择观看系统自动进行时移跳至某台新闻栏目10分钟前的画面开始播放，并且在我看完这条相关新闻后提醒我是否关注后续报道。同时提醒我，朋友张君推荐给我的关于昨天小米手机发布的相关节目。我顺便把之前突发事故进行了关注操作并转发给了喜欢天灾人祸的好友顾君，接着开始收看张君推荐给我的视频，这是儿子过来抢电视机要看动画片，我拿起我的pad进行了播放转移，拿着pad边看边到书房打开电脑看了看小米手机发布的相关网页，并在我的个人中心关注里面添加了“小米手机”关健词。然后看起了最新大片《美国队长》，晚上9点提醒儿子睡觉后，拿起pad把刚才看到一半的小米手机发布会视频转移到了电视机继续观看，之后回到卧室的电视上接着看刚才没看完美国队长。在看的同时顺便在pad上和几个同时看的网友讨论那片头发现的残骸到底是什么，我说那个是发现的外星人遗迹，结果看到结尾错了被几个网友调侃，看完后又和他们在pad上聊天扯到了这个美国队长只是复仇者联盟的前奏，掉了我不少胃口为此去百度百科恶补了一些复仇者联盟相关知识。。。发现竟然之前的绿巨人、钢铁侠和这个都是有关联的。顺便在pad选了钢铁侠2、雷神放到了我的收藏里面留着有空在回顾下。。。</p>
<p>这就是我理解的三网融合、三屏合一应该做的事情，不知看到现在你的是否觉得这离我们很远呢。我想着就是我们需要做的，而且我们有信心能够做到，恩起码可以演示试用，毕竟我们做技术的能打动领导的心也行，至于你说这场景那一天能应用到我们的平常百姓的生活里，那这就不是我能回答的了的了。</p>
<p>前不久雷军先生在谈及小米创业时说过“金山就像是在盐碱地里种草。为什么不在台风口放风筝呢?站在台风口，猪都能飞上天&#8221;。</p>
<p>现在的台网就好比是金山在盐碱地里种草，有成功的也有失败的，成功来源于坚持、执着、方法，失败来自于体制、方向、犹豫，但是作为广电体制内我们空有这节目资源的台风，为什么我们不能放风筝呢，至少风大了猪都能飞上天。地方网台总有他创新成功那天</p>
<p style="text-align: right;">写在无锡网络电视平台升级前</p>
<p style="text-align: right;">2011年中秋节之夜</p>
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		</item>
		<item>
		<title>更改VMware Update Manager下载文件夹</title>
		<link>http://226617.cn/archives/892.htm</link>
		<comments>http://226617.cn/archives/892.htm#comments</comments>
		<pubDate>Tue, 12 Jul 2011 02:50:48 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[vmware相关]]></category>
		<category><![CDATA[Update Manager]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=892</guid>
		<description><![CDATA[先停掉 Update Manager服务 找到Update Manager安装文件夹，64位系统注意在Program Files (x86)下面找 在安装文件夹内找到vci-integrity.xml 先备份 然后打开vci-integrity.xml 查找&#60;patchStore&#62;D:\VMware Update Manager\... ]]></description>
			<content:encoded><![CDATA[<p>先停掉 Update Manager服务<br />
找到Update Manager安装文件夹，64位系统注意在Program Files (x86)下面找<br />
在安装文件夹内找到vci-integrity.xml 先备份<br />
然后打开vci-integrity.xml<br />
查找&lt;patchStore&gt;D:\VMware Update Manager\Data\&lt;/patchStore&gt;<br />
把当中的路径改成新路径保存，然后启动Update Manager服务即可</p>
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		<item>
		<title>在两台dell 2950之间交换perc 5 raid硬盘</title>
		<link>http://226617.cn/archives/890.htm</link>
		<comments>http://226617.cn/archives/890.htm#comments</comments>
		<pubDate>Mon, 11 Jul 2011 03:52:49 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[硬件相关]]></category>
		<category><![CDATA[perc]]></category>
		<category><![CDATA[raid]]></category>
		<category><![CDATA[换硬盘]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=890</guid>
		<description><![CDATA[2台配置相同的dell 2950服务器，都采用了perc 5/i raid卡，一台是1块硬盘 raid0，另外一台是2块硬盘raid1。现在需要把2台机器的硬盘对换。 首先关机物理插拔并安装原位交换硬盘，然后开机，在raid... ]]></description>
			<content:encoded><![CDATA[<p>2台配置相同的dell 2950服务器，都采用了perc 5/i raid卡，一台是1块硬盘 raid0，另外一台是2块硬盘raid1。现在需要把2台机器的硬盘对换。<br />
首先关机物理插拔并安装原位交换硬盘，然后开机，在raid卡载入的时候会提示：<br />
<code><br />
Foreign configuration(s) found on adapter<br />
Press any key to continue, or 'C' to load the configuration utility.</p>
<p>Some configured disks have been removed from your system, or are no longer<br />
accessible. Please check your cables and also ensure all disks are present.<br />
Press any key to continue, or 'C' to load the configuration utility.<br />
</code><br />
这时候重复按 C 出现提示按 Y 重复按 Y，然后出现提示 按 C 的时候再重复按 C，直到进入raid 配置界面</p>
<p>这时候把光标移到controller 0 按 f2<br />
选择 foreign config 再选择 import 就能导入硬盘中的raid配置了</p>
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		<title>完美解决nginx环境下服务器上多站点WebShell访问限制问题</title>
		<link>http://226617.cn/archives/887.htm</link>
		<comments>http://226617.cn/archives/887.htm#comments</comments>
		<pubDate>Wed, 06 Jul 2011 01:26:57 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[linux相关]]></category>
		<category><![CDATA[nginx相关]]></category>
		<category><![CDATA[php相关]]></category>
		<category><![CDATA[nginx]]></category>
		<category><![CDATA[open_basedir]]></category>
		<category><![CDATA[php]]></category>
		<category><![CDATA[php-fpm]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=887</guid>
		<description><![CDATA[完美解决nginx环境下服务器上多站点WebShell访问限制问题 http://www.discuz.net/thread-1497466-1-1.html wget http://www.php.net/get/php-5.2.10.tar.gz/from/this/mirror wget http://php-fpm.org/downloads/php-5.2.10-fpm-0.5.13.diff.gz tar zxv... ]]></description>
			<content:encoded><![CDATA[<p>完美解决nginx环境下服务器上多站点WebShell访问限制问题</p>
<p>http://www.discuz.net/thread-1497466-1-1.html</p>
<p><code><br />
wget http://www.php.net/get/php-5.2.10.tar.gz/from/this/mirror<br />
wget http://php-fpm.org/downloads/php-5.2.10-fpm-0.5.13.diff.gz<br />
tar zxvf php-5.2.10.tar.gz<br />
gzip -cd php-5.2.10-fpm-0.5.11.diff.gz | patch -d php-5.2.10 -p1<br />
cd php-5.2.10/<br />
./configure --prefix=/usr/local/php --with-config-file-path=/usr/local/php/etc --with-mysql=/usr/local/mysql --with-mysqli=/usr/local/mysql/bin/mysql_config --with-iconv-dir=/usr/local --with-freetype-dir --with-jpeg-dir --with-png-dir --with-zlib --with-libxml-dir=/usr --enable-xml --disable-rpath --enable-discard-path --enable-safe-mode --enable-bcmath --enable-shmop --enable-sysvsem --enable-inline-optimization --with-curl --with-curlwrappers --enable-mbregex --enable-fastcgi --enable-fpm --enable-force-cgi-redirect --enable-mbstring --with-mcrypt --with-gd --enable-gd-native-ttf --with-openssl --with-mhash --enable-pcntl --enable-sockets --with-xmlrpc --enable-zip --enable-ftp --without-pear<br />
</code><br />
<code><br />
vi main/fopen_wrappers.c<br />
</code><br />
<code><br />
/* {{{ php_check_open_basedir<br />
*/<br />
PHPAPI int php_check_open_basedir_ex(const char *path, int warn TSRMLS_DC)<br />
{<br />
/* Only check when open_basedir is available */<br />
if (PG(open_basedir) &#038;&#038; *PG(open_basedir)) {<br />
char *pathbuf;<br />
char *ptr;<br />
char *end; </p>
<p>下面加上：<br />
char *env_document_root = sapi_getenv("DOCUMENT_ROOT", sizeof("DOCUMENT_ROOT")-1 TSRMLS_CC);<br />
if (php_check_specific_open_basedir(ptr, path TSRMLS_CC) == 0) {<br />
efree(env_document_root);<br />
return 0;<br />
}<br />
</code></p>
<p>然后保存，退出。</p>
<p>php.in的open_basedir配置:<br />
修改：<br />
;open_basedir =<br />
为<br />
open_basedir = &#8220;/tmp/:/var/tmp/&#8221; </p>
<p>重启<br />
/usr/local/php/sbin/php-fpm restart </p>
]]></content:encoded>
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		</item>
		<item>
		<title>如何安全的去除Nginx服务器的版本号</title>
		<link>http://226617.cn/archives/885.htm</link>
		<comments>http://226617.cn/archives/885.htm#comments</comments>
		<pubDate>Fri, 11 Mar 2011 02:29:22 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[nginx相关]]></category>
		<category><![CDATA[nginx]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=885</guid>
		<description><![CDATA[http { &#8230;&#8230;省略配置 sendfile on; tcp_nopush on; keepalive_timeout 65; tcp_nodelay on; server_tokens off; &#8230;&#8230;.省略配置 } 重启nginx /usr/local/webserver/nginx/bin/nginx -s reload 这是我的nginx+tomcat服务器上执行前... ]]></description>
			<content:encoded><![CDATA[<p>http {<br />
&#8230;&#8230;省略配置<br />
sendfile on;<br />
tcp_nopush on;<br />
keepalive_timeout 65;<br />
tcp_nodelay on;<br />
<strong>server_tokens off;</strong><br />
&#8230;&#8230;.省略配置<br />
}<br />
重启nginx /usr/local/webserver/nginx/bin/nginx -s reload</p>
<p>这是我的nginx+tomcat服务器上执行前后的对比结果<br />
[root@localhost ~]# curl &#8211;head 127.0.0.1<br />
HTTP/1.1 403 Forbidden<br />
Server: nginx/0.8.46<br />
Date: Fri, 11 Mar 2011 08:26:51 GMT<br />
Content-Type: text/html; charset=utf-8<br />
Content-Length: 169<br />
Connection: keep-alive</p>
<p>[root@localhost ~]# /usr/local/webserver/nginx/sbin/nginx -s reload<br />
[root@localhost ~]# curl &#8211;head 127.0.0.1<br />
HTTP/1.1 403 Forbidden<br />
Server: nginx<br />
Date: Fri, 11 Mar 2011 08:26:58 GMT<br />
Content-Type: text/html; charset=utf-8<br />
Content-Length: 162<br />
Connection: keep-alive</p>
<p>如果服务器跑的是nginx+php-fpm，这时候需要编辑php-fpm配置文件 如fcgi.conf、fastcgi.conf(要看你是什么配置文件名)，久违的403报错，看看，有没有nginx版本泄露的信息：</p>
<p>fastcgi_param SERVER_SOFTWARE nginx/$nginx_version;<br />
改为fastcgi_param SERVER_SOFTWARE nginx;</p>
<p>记得平滑重启下 平滑重启：<br />
/usr/local/webserver/nginx/sbin/nginx -s reload</p>
<p>转自：http://hi.baidu.com/yuhongchun027/blog/item/a4b25f774db3620fb051b993.html</p>
]]></content:encoded>
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		</item>
		<item>
		<title>[转]基于SSD的数据库性能优化</title>
		<link>http://226617.cn/archives/882.htm</link>
		<comments>http://226617.cn/archives/882.htm#comments</comments>
		<pubDate>Tue, 22 Feb 2011 02:35:04 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[硬件相关]]></category>
		<category><![CDATA[SSD]]></category>
		<category><![CDATA[数据库]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=882</guid>
		<description><![CDATA[NOR和NAND NOR和NAND都是闪存技术的一种，NOR是Intel公司开发的，它有点类似于内存，允许通过地址直接访问任何一个内存单元，缺点是：密度低 （容量小），写入和擦除的速度很慢。NAND是东芝公... ]]></description>
			<content:encoded><![CDATA[<p><strong>NOR和NAND</strong></p>
<p>NOR和NAND都是闪存技术的一种，NOR是Intel公司开发的，它有点类似于内存，允许通过地址直接访问任何一个内存单元，缺点是：密度低 （容量小），写入和擦除的速度很慢。NAND是东芝公司开发的，它密度高（容量大），写入和擦除的速度都很快，但是必须通过特定的IO接口经过地址转换之 后才可以访问，有些类似于磁盘。</p>
<p>我们现在广泛使用的U盘，SD卡，SSD都属于NAND类型，厂商将flash memory封装成为不同的接口，比如Intel的SSD就是采用了SATA的接口，访问与普通SATA磁盘一样，还有一些企业级的闪存卡，比如FusionIO，则封装为PCIe接口。</p>
<p><strong>SLC和MLC</strong></p>
<p>SLC是单极单元，MLC是多级单元，两者的差异在于每单元存储的数据量（密度），SLC每单元只存储一位，只包含0和1两个电压符，MLC每单元 可以存储两位，包含四个电压符（00,01,10,11）。显然，MLC的存储容量比SLC大，但是SLC更简单可靠，SLC读取和写入的速度都比MLC 更快，而且SLC比MLC更耐用，MLC每单元可擦除1w次，而SLC可擦除10w次，所以，企业级的闪存产品一般都选用SLC，这也是为什么企业级产品 比家用产品贵很多的原因。</p>
<p><strong>SSD的技术特点</strong></p>
<p>SSD与传统磁盘相比，第一是没有机械装置，第二是由磁介质改为了电介质。在SSD内部有一个<strong>FTL</strong>(Flash Transalation Layer)，它相当于磁盘中的控制器，主要功能就是作地址映射，将flash memory的物理地址映射为磁盘的LBA逻辑地址，并提供给OS作透明访问。</p>
<p>SSD没有传统磁盘的寻道时间和延迟时间，所以SSD可以提供非常高的随机读取能力，这是它的最大优势，SLC类型的SSD通常可以提供超过 35000的IOPS，传统15k的SAS磁盘，最多也只能达到160个IOPS，这对于传统磁盘来说几乎就是个天文数字。SSD连续读的能力相比普通磁 盘优势并不明显，因为连续读对于传统磁盘来说，并不需要寻道时间，15k的SAS磁盘，连续读的吞吐能力可以达到130MB，而SLC类型的SSD可以达 到170-200MB，我们看到在吞吐量方面，SSD虽然比传统磁盘高一些，但优势虽然并不明显。</p>
<p>SSD的写操作比较特殊，SSD的最小写入单元为4KB，称为页(page)，当写入空白位置时可以按照4KB的单位写入，但是如果需要改写某个单 元时，则需要一个额外的擦除（erase）动作，擦除的单位一般是128个page（512KB），每个擦除单元称为块（block）。如果向一个空白的 page写入信息时，可以直接写入而无需擦除，但是如果需要改写某个存储单元（page）的数据，必须首先将整个block读入缓存，然后修改数据，并擦 除整个block的数据，最后将整个block写入，很显然，SSD改写数据的代价很高，SSD的这个特性，我们称之为erase-before- write。</p>
<p>经过测试，SLC  SSD的随即写性能可以达到3000个左右的IOPS，连续写的吞吐量可以达到170-200MB，这个数据还是比传统磁盘高出不少。但是，随着SSD的 不断写入，当越来越多的数据需要被改写时，写的性能就会逐步下降。经过我们的测试，SLC在这个方面要明显好于MLC，在长时间写入后，MLC随机写IO 下降得非常厉害，而SLC表现则比较稳定。为了解决这个问题，各个厂商都有很多策略来防止写性能下降的问题。</p>
<p><strong>wear leveling</strong></p>
<p>因为SSD存在“写磨损”的问题，当某个单元长时间被反复擦写时（比如Oracle  redo），不仅会造成写入的性能问题，而且会大大缩短SSD的使用寿命，所以必须设计一个均衡负载的算法来保证SSD的每个单元能够被均衡的使用，这就 是wear leveling，称为损耗均衡算法。</p>
<p>Wear leveling也是SSD内部的FTL实现的，它通过数据迁移来达到均衡损耗的目的。Wear  leveling依赖于SSD中的一部分保留空间，基本原理是在SSD中设置了两个block pool，一个是free block  pool（空闲池），一个是数据池（data block  pool），当需要改写某个page时（如果写入原有位置，必须先擦除整个block，然后才能写入数据），并不写入原有位置（不需要擦除的动作），而是 从空闲池中取出新的block，将现有的数据和需要改写的数据合并为新的block，一起写入新的空白block，原有的block被标识为 invalid状态（等待被擦除回收），新的block则进入数据池。后台任务会定时从data  block中取出无效数据的block，擦除后回收到空闲池中。这样做的好处在于，一是不会反复擦写同一个block，二是写入的速度会比较快(省略了擦 除的动作)。</p>
<p><a href="http://www.hellodba.net/wp-content/uploads/2010/10/ssd_wear_leveling.jpg"><img title="ssd_wear_leveling" src="http://www.hellodba.net/wp-content/uploads/2010/10/ssd_wear_leveling.jpg" alt="" width="558" height="428" /></a></p>
<p>Wear  leveling分为两种：动态损耗均衡和静态损耗均衡，两者的原理一致，区别在于动态算法只会处理动态数据，比如数据改写时才会触发数据迁移的动作，对 静态数据不起作用，而静态算法可以均衡静态数据，当后台任务发现损耗很低的静态数据块时，将其迁移到其他数据库块上，将这些块放入空闲池中使用。从均衡的 效果来看，静态算法要好于动态算法，因为几乎所有的block都可以被均衡的使用，SSD的寿命会大大延长，但是静态算法的缺点是当数据迁移时，可能会导 致写性能下降。</p>
<p><strong>写入放大</strong></p>
<p>因为SSD的<strong>erase-before-write</strong>的特性，所以就出现了一个写入放大的概念，比如你想改写4K的数据，必须首先将整个擦除块（512KB）中的数据读出到缓存中，改写后，将整个块一起写入，这时你实际写入了512KB的数据，写入放大系数是128。写入放大最好的情况是1，就是不存在放大的情况。</p>
<p>Wear leveling算法可以有效缓解写入放大的问题，但是不合理的算法依然会导致写入放大，比如用户需要写入4k数据时，发现free  block pool中没有空白的block，这时就必须在data block  pool中选择一个包含无效数据的block，先读入缓存中，改写后，将整个块一起写入，采用wear leveling算法依然会存在写入放大的问题。</p>
<p>通过为SSD预留更多空间，可以显著缓解写入放大导致的性能问题。根据我们的测试结果，MLC  SSD在长时间的随机写入后，性能下降很明显（随机写IOPS甚至降低到300）。如果为wear leveling预留更多空间，就可以显著改善MLC  SSD在长时间写操作之后的性能下降问题，而且保留的空间越多，性能提升就越明显。相比较而言，SLC  SSD的性能要稳定很多（IOPS在长时间随机写后，随机写可以稳定在3000 IOPS），我想应该是SLC  SSD的容量通常比较小（32G和64G），而用于wear leveling的空间又比较大的原因。</p>
<p><strong>数据库IO特点分析</strong></p>
<p>IO有四种类型：连续读，随机读，随机写和连续写，连续读写的IO size通常比较大（128KB-1MB），主要衡量吞吐量，而随机读写的IO   size比较小(小于8KB)，主要衡量IOPS和响应时间。数据库中的全表扫描是连续读IO，索引访问则是典型的随机读IO，日志文件是连续写IO，而 数据文件则是随机写IO。</p>
<p>数据库系统基于传统磁盘访问特性来设计，最大特点是日志文件采用<strong>sequential logging</strong>，数据库 中的日志文件，要求必须在事务提交时写入到磁盘，对响应时间的要求很高，所以设计为顺序写入的方式，可以有效降低磁盘寻道花费的时间，减少延迟时间。日志 文件的顺序写入，虽然是物理位置是连续的，但是并不同于传统的连续写类型，日志文件的IO  size很小（通常小于4K）,每个IO之间是独立的（磁头必须抬起来重新寻道，并等待磁盘转动到相应的位置），而且间隔很短，数据库通过log  buffer（缓存）和group commit的方式（批量提交）来达到提高IO  size的大小，并减少IO的次数，从而得到更小的响应延迟，所以日志文件的顺序写入可以被认为是“<strong>连续位置的随机写入</strong>”，瓶颈还是在IOPS，而不是吞吐量。</p>
<p>数据文件采用<strong>in place update</strong>的方式，意思是数据文件的修改都是写入到原来的位置，数据文件不同 于日志文件，并不会在事务commit时写入数据文件，只有当数据库发现dirty  buffer过多或者需要做checkpoint动作时，才会刷新这些dirty  buffer到相应的位置，这是一个异步的过程，通常情况下，数据文件的随机写入对IO的要求并不是特别高，只要满足checkpoint和dirty  buffer的要求就可以了。</p>
<p><strong>SSD的IO特点分析</strong></p>
<p>1.随机读能力非常好，连续读性能一般，但比普通SAS磁盘好。</p>
<p>2.不存在磁盘寻道的延迟时间，随机写和连续写的响应延迟差异不大。</p>
<p>3.erase-before-write特性，造成写入放大，影响写入的性能。</p>
<p>4.写磨损特性，采用wear leveling算法延长寿命，但同时会影响读的性能。</p>
<p>5.读和写的IO响应延迟不对等（读要大大好于写），而普通磁盘读和写的IO响应延迟差异很小。</p>
<p>6.连续写比随机写性能好，比如1M顺序写比128个8K的随即写要好很多，因为随即写会带来大量的擦除。</p>
<p><strong>基于SSD的上述特性，如果将数据库全部放在SSD上，可能会有以下的问题：</strong></p>
<p>1.日志文件sequential logging会反复擦写同一位置，虽然有损耗均衡算法，但是长时间写入依然会导致性能下降。</p>
<p>2.数据文件in place update会产生大量的随机写入，erase-before-write会产生写入放大。</p>
<p>3.数据库读写混合型应用，存在大量的随机写入，同时会影响读的性能，产生大量的IO延迟。</p>
<p><strong>基于SSD的数据库优化法则</strong>：</p>
<p>基于SSD的优化就是解决erase-before-write产生的写入放大的问题，不同类型的IO分离，减少写操作带来的性能影响。</p>
<p>1.将sequential logging修改为In-page logging，避免对相同位置的反复擦写。</p>
<p>2.通过缓存写入的方式将大量的in-place update随机写入合并为少量顺序写入。</p>
<p>3.利用SSD随机读写能力高的特点，减少写增加读，从而达到整体性能的提升。</p>
<p><strong>In-page logging</strong></p>
<p>In-page logging是基于SSD对数据库sequential logging的一种优化方法，数据库中的sequential  logging对传统磁盘是非常有利的，可以大大提高响应时间，但是对于SSD就是噩梦，因为需要对同一位置反复擦写，而wear  leveling算法虽然可以平衡负载，但是依然会影响性能，并产生大量的IO延迟。所以In-page  logging将日志和数据合并，将日志顺序写入改为随机写入，基于SSD对随机写和连续写IO响应延迟差异不大的特性，避免对同一位置反复擦写，提高整 体性能。</p>
<p>In-page logging基本原理：在data buffer中，有一个in-memory log sector的结构，类似于log  buffer，每个log sector是与data block对应的。在data buffer中，data和log并不合并，只是在data  block和log sector之间建立了对应关系，可以将某个data block的log分离出来。但是，在SSD底层的flash  memory中，数据和日志是存放在同一个block（擦除单元），每个block都包含data page和log page。</p>
<p>当日志信息需要写入的时候（log buffer空间不足或者事务提交），日志信息会写入到flash  memory对应的block中，也就是说日志信息是分布在很多不同的block中的，而每个block内的日志信息是append  write，所以不需要擦除的动作。当某个block中的log  sector写满的时候，这时会发生一个动作，将整个block中的信息读出，然后应用block中的log  sector，就可以得到最新的数据，然后整个block写入，这时，block中的log sector是空白的。</p>
<p>在in-page logging方法中，data buffer中的dirty block是不需要写入到flash  memory中的，就算dirty buffer需要被交换出去，也不需要将它们写入flash  memory中。当需要读取最新的数据，只要将block中的数据和日志信息合并，就可以得到最新的数据。</p>
<p>In-page logging方法，将日志和数据放在同一个擦除单元内，减少了对flash相同位置的反复擦写，而且不需要将dirty  block写入到flash中，大量减少了in-place  update的随机写入和擦除的动作。虽然在读取时，需要做一个merge的操作，但是因为数据和日志存放在一起，而且SSD的随机读取能力很高，in- page logging可以提高整体的性能。</p>
<p><a href="http://www.hellodba.net/wp-content/uploads/2010/10/in-page-logging.jpg"><img title="in-page logging" src="http://www.hellodba.net/wp-content/uploads/2010/10/in-page-logging.jpg" alt="" width="430" height="299" /></a></p>
<p><strong>SSD作为写cache—append write<br />
</strong></p>
<p>SSD可以作为磁盘的写cache，因为SSD连续写比随机写性能好，比如：1M顺序写比128个8K的随机写要好很多，我们可以将大量随机写合并 成为少量顺序写，增加IO的大小，减少IO(擦除)的次数，提高写入性能。这个方法与很多NoSQL产品的append  write类似，即不改写数据，只追加数据，需要时做合并处理。</p>
<p>基本原理：当dirty block需要写入到数据文件时，并不直接更新原来的数据文件，而是首先进行IO合并，将很多个8K的dirty  block合并为一个512KB的写入单元，并采用append write的方式写入到一个cache  file中（保存在SSD上），避免了擦除的动作，提高了写入性能。cache file中的数据采用循环的方式顺序写入，当cache  file空间不足够时，后台进程会将cache file中的数据写入到真正的数据文件中（保存在磁盘上），这时进行第二次IO合并，将cache  file内的数据进行合并，整合成为少量的顺序写入，对于磁盘来说，最终的IO是1M的顺序写入，顺序写入只会影响吞吐量，而磁盘的吞吐量不会成为瓶颈， 将IOPS的瓶颈转化为吞吐量的瓶颈，从而提升了整体系统能力。</p>
<p>读取数据时，必须首先读取cache file，而cache file中的数据是无序存放的，为了快速检索cache  file中的数据，一般会在内存中为cache file建立一个索引，读取数据时会先查询这个索引，如果命中查询cache  file，如果没有命中，再读取data file（普通磁盘），所以，这种方法实际不仅仅是写cache，同时也起到了读cache的作用。</p>
<p>SSD并不适合放数据库的日志文件，虽然日志文件也是append write，但是因为日志文件的IO  size比较小，而且必须同步写入，无法做合并处理，对SSD来说，需要大量的擦除动作。我们也曾经尝试把redo  log放在SSD上，考虑到SSD的随机写入也可以达到3000 IOPS，而且响应延时比磁盘低很多，但是这依赖于SSD本身的wear  leveling算法是否优秀，而且日志文件必须是独立存放的，如果日志文件的写入是瓶颈，也算是一种解决方案吧。通常情况下，我还是建议日志文件放在普 通磁盘上，而不是SSD。</p>
<p><strong>SSD作为读cache—flashcache</strong></p>
<p>因为大部分数据库都是读多写少的类型，所以SSD作为数据库flashcache是优化方案中最简单的一种，它可以充分利用SSD读性能的优势，又 避免了SSD写入的性能问题。实现的方法有很多种，可以在读取数据时，将数据同时写入SSD，也可以在数据被刷出buffer时，写入到SSD。读取数据 时，首先在buffer中查询，然后在flashcache中查询，最后读取datafile。</p>
<p>SSD作为flashcache与memcache作为数据库外部cache的最大区别在于，SSD掉电后数据是不丢失的，这也引起了另外一个思 考，当数据库发生故障重启后，flashcache中的数据是有效还是无效？如果是有效的，那么就必须时刻保证flashcache中数据的一致性，如果 是无效的，那么flashcache同样面临一个预热的问题（这与memcache掉电后的问题一样）。目前，据我所知，基本上都认为是无效的，因为要保 持flashcache中数据的一致性，非常困难。</p>
<p>flashcache作为内存和磁盘之间的二级cache，除了性能的提升以外，从成本的角度看，SSD的价格介于memory和disk之间，作为两者之间的一层cache，可以在性能和价格之间找到平衡。</p>
<p><strong>总结</strong></p>
<p>随着SSD价格不断降低，容量和性能不断提升，SSD取代磁盘只是个时间问题。</p>
<p>Tape is Dead，Disk is Tape，Flash is Disk，RAM Locality is King.        Jim Gray</p>
<p>来源：http://www.hellodba.net/2010/10/ssd-database-2.html</p>
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		<title>解决编码为gb2312页面ajax交互汉字乱码的问题</title>
		<link>http://226617.cn/archives/876.htm</link>
		<comments>http://226617.cn/archives/876.htm#comments</comments>
		<pubDate>Tue, 25 Jan 2011 02:44:47 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[php相关]]></category>
		<category><![CDATA[软件相关]]></category>
		<category><![CDATA[ajax]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=876</guid>
		<description><![CDATA[ajax只支持utf-8格式，不能支持gb2312编码格式，所以经常遇到gb2312的编码的程序使用ajax就出现乱码，刚找到一种解决方案是： 服务器端传送的数据仍是gb2312编码，客户端用js将汉字转变成utf8编码... ]]></description>
			<content:encoded><![CDATA[<p>ajax只支持utf-8格式，不能支持gb2312编码格式，所以经常遇到gb2312的编码的程序使用ajax就出现乱码，刚找到一种解决方案是：</p>
<p>服务器端传送的数据仍是gb2312编码，客户端用js将汉字转变成utf8编码显示在页面</p>
<p>search.php</p>

<div class="wp_syntax"><table><tr><td class="line_numbers"><pre>1
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</pre></td><td class="code"><pre class="php" style="font-family:monospace;"><span style="color: #000000; font-weight: bold;">&lt;?php</span>
<span style="color: #990000;">header</span><span style="color: #009900;">&#40;</span><span style="color: #0000ff;">&quot;Content-type: text/html; charset=gb2312&quot;</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">;</span>
<span style="color: #b1b100;">include</span> <span style="color: #0000ff;">'./search.htm'</span><span style="color: #339933;">;</span>
<span style="color: #000000; font-weight: bold;">?&gt;</span></pre></td></tr></table></div>

<p>search.htm</p>

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</pre></td><td class="code"><pre class="html" style="font-family:monospace;">&lt;!DOCTYPE html PUBLIC &quot;-//W3C//DTD XHTML 1.0 Transitional//EN&quot; &quot;http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd&quot;&gt;
&lt;html xmlns=&quot;http://www.w3.org/1999/xhtml&quot;&gt;
&lt;head&gt;
&lt;meta http-equiv=&quot;Content-Type&quot; content=&quot;text/html; charset=gb2312&quot; /&gt;
&lt;title&gt;高级搜索&lt;/title&gt;
&lt;/head&gt;
&lt;body&gt;
&lt;h3&gt;高级搜索&lt;/h3&gt;
&lt;form method=&quot;post&quot; action=&quot;&quot;&gt;
  学校类型:
  &lt;select name=&quot;schooltype&quot;&gt;
    &lt;option value=&quot;&quot;&gt;全部&lt;/option&gt;
    &lt;option value=&quot;1&quot;&gt;小学&lt;/option&gt;
    &lt;option value=&quot;2&quot;&gt;初中&lt;/option&gt;
  &lt;/select&gt;
  学校名称:
  &lt;select name=&quot;sid&quot; id=&quot;sid&quot;&gt;
    &lt;option value=&quot;&quot;&gt;请选择学校&lt;/option&gt;
  &lt;/select&gt;
&lt;/form&gt;
&lt;script type=&quot;text/javascript&quot;&gt;
function ajax(settings) {
    var XHR = window.ActiveXObject ? new ActiveXObject(&quot;Microsoft.XMLHTTP&quot;) : new XMLHttpRequest(), successed = false;
    XHR.open(settings.type, settings.url);
    if(settings.type == 'post')
     XHR.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
    XHR.send((!settings.cache ? 'time=' + new Date().getTime() + '&amp;' : '') + settings.data);
    settings.loader();
    setTimeout(function() {
        if(!successed) {
            alert('Resquest timeout!');
            XHR.abort();
        }
    }, settings.timeout);
    XHR.onreadystatechange = function() {
        if (XHR.readyState == 4 &amp;&amp; XHR.status == 200) {
            settings.callback(XHR.responseText.replace(/(^\s*)|(\s*$)/g, &quot;&quot;));
        }
        successed = true;
    }
}
function a(t) {
ajax({
  type: 'post',
  url: 'ajax.php',
  data: 'schooltype=' + t,
  timeout: 8000,
  cache: true,
  loader: function() {},
  callback: function(d) {
   var arr = eval(d);
   if(typeof(arr) == 'object') {
    var obj, option;
    document.getElementById('sid').innerHTML = '';
    for(var i = 0; obj = arr; i ++) {
     option = document.createElement('option');
     option.value = obj[0];
     option.innerHTML = txt2utf8(obj[1], '&amp;#');
     document.getElementById('sid').appendChild(option);
    }
   }
  }
})
}
function txt2utf8(string, prefix){
    for(var i=0,utf8=[];i&lt;string.length;utf8.push((prefix||'\\u')+string.charCodeAt(i++)));
    return utf8.join('');
}
a(0);
&lt;/script&gt;
&lt;/body&gt;
&lt;/html&gt;</pre></td></tr></table></div>

<p>ajax.php</p>

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</pre></td><td class="code"><pre class="php" style="font-family:monospace;"><span style="color: #000000; font-weight: bold;">&lt;?php</span>
<span style="color: #990000;">header</span><span style="color: #009900;">&#40;</span><span style="color: #0000ff;">&quot;Content-type: text/html; charset=gb2312&quot;</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">;</span>
<span style="color: #000088;">$schooltype</span> <span style="color: #339933;">=</span> <span style="color: #339933;">!</span><span style="color: #990000;">empty</span><span style="color: #009900;">&#40;</span><span style="color: #000088;">$_POST</span><span style="color: #009900;">&#91;</span><span style="color: #0000ff;">'schooltype'</span><span style="color: #009900;">&#93;</span><span style="color: #009900;">&#41;</span> ? <span style="color: #000088;">$_POST</span><span style="color: #009900;">&#91;</span><span style="color: #0000ff;">'schooltype'</span><span style="color: #009900;">&#93;</span> <span style="color: #339933;">:</span> <span style="color: #cc66cc;">0</span><span style="color: #339933;">;</span>
<span style="color: #b1b100;">switch</span><span style="color: #009900;">&#40;</span><span style="color: #000088;">$schooltype</span><span style="color: #009900;">&#41;</span> <span style="color: #009900;">&#123;</span>
    <span style="color: #b1b100;">case</span> <span style="color: #cc66cc;">0</span><span style="color: #339933;">:</span>
        <span style="color: #b1b100;">echo</span> <span style="color: #0000ff;">&quot;[['40', '太平溪镇花栗包完全小学'],['41', '太平溪镇长岭黑龙江希望小学'],['42', '乐天溪镇初级中学'],['43', '乐天溪镇莲沱初级中学']]&quot;</span><span style="color: #339933;">;</span>
        <span style="color: #b1b100;">break</span><span style="color: #339933;">;</span>
    <span style="color: #b1b100;">case</span> <span style="color: #cc66cc;">1</span><span style="color: #339933;">:</span>
        <span style="color: #b1b100;">echo</span> <span style="color: #0000ff;">&quot;[['40', '太平溪镇花栗包完全小学'],['41', '太平溪镇长岭黑龙江希望小学']]&quot;</span><span style="color: #339933;">;</span>
        <span style="color: #b1b100;">break</span><span style="color: #339933;">;</span>
    <span style="color: #b1b100;">case</span> <span style="color: #cc66cc;">2</span><span style="color: #339933;">:</span>
        <span style="color: #b1b100;">echo</span> <span style="color: #0000ff;">&quot;[['42', '乐天溪镇初级中学'],['43', '乐天溪镇莲沱初级中学']]&quot;</span><span style="color: #339933;">;</span>
        <span style="color: #b1b100;">break</span><span style="color: #339933;">;</span>
    <span style="color: #b1b100;">default</span><span style="color: #339933;">:</span>
        <span style="color: #b1b100;">break</span><span style="color: #339933;">;</span>
<span style="color: #009900;">&#125;</span>
<span style="color: #000000; font-weight: bold;">?&gt;</span></pre></td></tr></table></div>

<p>这个提到的方案有：<br />
一，服务器端json数据用php的iconv函数转换：iconv(&#8216;GB2312&#8242;, &#8216;UTF8&#8242;, &#8220;被转换字符串，输出到浏览器&#8221;);<br />
      客户端获取UTF8数据，再转成gb2312：</p>

<div class="wp_syntax"><table><tr><td class="line_numbers"><pre>1
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</pre></td><td class="code"><pre class="javascript" style="font-family:monospace;"><span style="color: #003366; font-weight: bold;">function</span> gb2utf8<span style="color: #009900;">&#40;</span>data<span style="color: #009900;">&#41;</span><span style="color: #009900;">&#123;</span><span style="color: #006600; font-style: italic;">//GB编码是，ie通过二进制码utf8-&gt;gbk转为中文  </span>
     <span style="color: #003366; font-weight: bold;">var</span> glbEncode <span style="color: #339933;">=</span> <span style="color: #009900;">&#91;</span><span style="color: #009900;">&#93;</span><span style="color: #339933;">;</span>  
     gb2utf8_data <span style="color: #339933;">=</span> data<span style="color: #339933;">;</span>  
     execScript<span style="color: #009900;">&#40;</span><span style="color: #3366CC;">&quot;gb2utf8_data = MidB(gb2utf8_data, 1)&quot;</span><span style="color: #339933;">,</span> <span style="color: #3366CC;">&quot;VBScript&quot;</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">;</span>  
     <span style="color: #003366; font-weight: bold;">var</span> t<span style="color: #339933;">=</span>escape<span style="color: #009900;">&#40;</span>gb2utf8_data<span style="color: #009900;">&#41;</span>.<span style="color: #660066;">replace</span><span style="color: #009900;">&#40;</span><span style="color: #009966; font-style: italic;">/%u/g</span><span style="color: #339933;">,</span><span style="color: #3366CC;">&quot;&quot;</span><span style="color: #009900;">&#41;</span>.<span style="color: #660066;">replace</span><span style="color: #009900;">&#40;</span><span style="color: #339933;">/</span><span style="color: #009900;">&#40;</span>.<span style="color: #009900;">&#123;</span><span style="color: #CC0000;">2</span><span style="color: #009900;">&#125;</span><span style="color: #009900;">&#41;</span><span style="color: #009900;">&#40;</span>.<span style="color: #009900;">&#123;</span><span style="color: #CC0000;">2</span><span style="color: #009900;">&#125;</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">/</span>g<span style="color: #339933;">|&gt;,</span><span style="color: #3366CC;">&quot;%$2%$1&quot;</span><span style="color: #009900;">&#41;</span>.<span style="color: #660066;">replace</span><span style="color: #009900;">&#40;</span><span style="color: #339933;">/%</span><span style="color: #009900;">&#40;</span><span style="color: #009900;">&#91;</span>A<span style="color: #339933;">-</span>Z<span style="color: #009900;">&#93;</span>.<span style="color: #009900;">&#41;</span><span style="color: #339933;">%</span><span style="color: #009900;">&#40;</span>.<span style="color: #009900;">&#123;</span><span style="color: #CC0000;">2</span><span style="color: #009900;">&#125;</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">/</span>g<span style="color: #339933;">|&gt;,</span><span style="color: #3366CC;">&quot;@$1$2&quot;</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">;</span>  
     t<span style="color: #339933;">=</span>t.<span style="color: #660066;">split</span><span style="color: #009900;">&#40;</span><span style="color: #3366CC;">&quot;@&quot;</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">;</span>  
     <span style="color: #003366; font-weight: bold;">var</span> i<span style="color: #339933;">=</span><span style="color: #CC0000;">0</span><span style="color: #339933;">,</span>j<span style="color: #339933;">=</span>t.<span style="color: #660066;">length</span><span style="color: #339933;">,</span>k<span style="color: #339933;">;</span>  
     <span style="color: #000066; font-weight: bold;">while</span><span style="color: #009900;">&#40;</span><span style="color: #339933;">++</span>i<span style="color: #339933;">&lt;</span>j<span style="color: #009900;">&#41;</span><span style="color: #339933;">&gt;</span>  
         k<span style="color: #339933;">=</span>t.<span style="color: #660066;">substring</span><span style="color: #009900;">&#40;</span><span style="color: #CC0000;">0</span><span style="color: #339933;">,</span><span style="color: #CC0000;">4</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">;</span>  
         <span style="color: #000066; font-weight: bold;">if</span><span style="color: #009900;">&#40;</span><span style="color: #339933;">!</span>glbEncode<span style="color: #009900;">&#91;</span>k<span style="color: #009900;">&#93;</span><span style="color: #009900;">&#41;</span> <span style="color: #009900;">&#123;</span>  
             gb2utf8_char <span style="color: #339933;">=</span> <span style="color: #000066; font-weight: bold;">eval</span><span style="color: #009900;">&#40;</span><span style="color: #3366CC;">&quot;0x&quot;</span><span style="color: #339933;">+</span>k<span style="color: #009900;">&#41;</span><span style="color: #339933;">;</span>  
             execScript<span style="color: #009900;">&#40;</span><span style="color: #3366CC;">&quot;gb2utf8_char = Chr(gb2utf8_char)&quot;</span><span style="color: #339933;">,</span> <span style="color: #3366CC;">&quot;VBScript&quot;</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">;</span>  
             glbEncode<span style="color: #009900;">&#91;</span>k<span style="color: #009900;">&#93;</span><span style="color: #339933;">=</span>escape<span style="color: #009900;">&#40;</span>gb2utf8_char<span style="color: #009900;">&#41;</span>.<span style="color: #660066;">substring</span><span style="color: #009900;">&#40;</span><span style="color: #CC0000;">1</span><span style="color: #339933;">,</span><span style="color: #CC0000;">6</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">;</span>  
         <span style="color: #009900;">&#125;</span>  
         t<span style="color: #339933;">=</span>glbEncode<span style="color: #009900;">&#91;</span>k<span style="color: #009900;">&#93;</span><span style="color: #339933;">+</span>t.<span style="color: #660066;">substring</span><span style="color: #009900;">&#40;</span><span style="color: #CC0000;">4</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">;</span>  
     <span style="color: #009900;">&#125;</span>  
     gb2utf8_data <span style="color: #339933;">=</span> gb2utf8_char <span style="color: #339933;">=</span> <span style="color: #003366; font-weight: bold;">null</span><span style="color: #339933;">;</span>  
     <span style="color: #000066; font-weight: bold;">return</span> unescape<span style="color: #009900;">&#40;</span>t.<span style="color: #660066;">join</span><span style="color: #009900;">&#40;</span><span style="color: #3366CC;">&quot;%&quot;</span><span style="color: #009900;">&#41;</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">;</span>  
<span style="color: #009900;">&#125;</span></pre></td></tr></table></div>

<p>二，header(&#8220;Content-type&#8221;, &#8220;application/x-www-form-urlencoded; charset=GBK&#8221;); //输出头标，设置为GBK编码</p>
<p>三，在ajax请求数据前调用上面的方法指定请求使用的字符集:xmlHttp.setRequestHeader( &#8220;Content-Type&#8221;, &#8220;application/x-www-form-urlencoded;charset=gbk&#8221;);</p>
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		<title>防盗链技术终极解决方案</title>
		<link>http://226617.cn/archives/872.htm</link>
		<comments>http://226617.cn/archives/872.htm#comments</comments>
		<pubDate>Tue, 21 Dec 2010 02:50:49 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[只谈技术]]></category>
		<category><![CDATA[软件相关]]></category>
		<category><![CDATA[Squid]]></category>
		<category><![CDATA[防盗链]]></category>

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		<description><![CDATA[防盗链技术现状： 1、通过识别Referer确认请求来源页面 2、Apache，squid等都能对Referer进行识别 3、通过ActiveX显示的内容不向服务器提供Referer Header（例如，Flash，WindowsMedia视频等） 4、流媒体的RTS... ]]></description>
			<content:encoded><![CDATA[<p>防盗链技术现状：<br />
    1、通过识别Referer确认请求来源页面<br />
    2、Apache，squid等都能对Referer进行识别<br />
    3、通过ActiveX显示的内容不向服务器提供Referer Header（例如，Flash，WindowsMedia视频等）<br />
    4、流媒体的RTSP协议也不向服务器提供Referer Header<br />
    5、通过服务器端程序代码实现</p>
<p>防盗链应用现状：<br />
    1、对图片、HTML等可以实现防盗链<br />
    2、无法对Flash，WindowsMedia视频（MMS，RTSP）实现防盗链<br />
    3、服务器端程序代码实现的防盗链无法通过CDN加速</p>
<p>对于Flash，WindowsMedia视频这种占用流量较大的服务无法实现防盗链，对一个依靠这类内容作为盈利点的网站来说是非常头疼的，俺通过一些研究以及测试实现了采用Cookie技术的防盗链解决方案，完美的解决了对Flash，WindowsMedia视频的防盗链。</p>
<p>首先发现虽然ActiveX插件不传递Referer，但是却忠实的传递Cookie。于是在显示ActiveX的页面的<head> </head>标签内嵌入一段代码：<br />
<script> document.cookie="Cache=vod;domain=domain.com;path=/"; </script></p>
<p>这段代码用 javascript 设置了一段 Cookie: Cache=vod</p>
<p>然后通过各种ACL来判断这个Cookie的存在以及验证其值的操作了</p>
<p>Squid:<br />
    建立脚本 /usr/local/squid/libexec/squid_cookie.pl<br />
&#8212;&#8212;&#8212;&#8211;<br />
#!/usr/bin/perl -w<br />
# programmed by oknet http://blog.sina.com.cn/m/oknet<br />
# 这个脚本仅仅是验证了Cache这个cookie的存在，没有严格的校验其值。<br />
# This is the cookie to check for.<br />
$COOKIE=&#8221;Cache=&#8221;;<br />
# disable output buffering<br />
$|=1;<br />
# cookie matches?<br />
while (<STDIN>) {<br />
         chop;<br />
         $cookie=$_;<br />
         if( $cookie =~ /$COOKIE/i) {<br />
                 print &#8220;OK\n&#8221;;<br />
         } else { print &#8220;ERR\n&#8221;; }<br />
}<br />
&#8212;&#8212;&#8212;&#8211;<br />
    然后在squid.conf添加：<br />
external_acl_type download children=15 %{Cookie} /usr/local/squid/libexec/squid_cookie.pl<br />
acl dl external download<br />
    然后选择需要进行防盗链的文件类型：<br />
acl filetype url_regex -i \.wmv<br />
acl filetype url_regex -i \.wma<br />
acl filetype url_regex -i \.asf<br />
acl filetype url_regex -i \.asx<br />
acl filetype url_regex -i \.avi<br />
acl filetype url_regex -i \.mp3<br />
acl filetype url_regex -i \.smi<br />
acl filetype url_regex -i \.rm<br />
acl filetype url_regex -i \.ram<br />
acl filetype url_regex -i \.rmvb<br />
acl filetype url_regex -i \.swf<br />
acl filetype url_regex -i \.mpg<br />
acl filetype url_regex -i \.mpeg<br />
acl filetype url_regex -i \.mov<br />
acl filetype url_regex -i \.zip<br />
acl filetype url_regex -i \.mid<br />
    如果仅仅只是禁止用户访问的话，就没意思了，要让盗链者帮我们宣传我们的网站，特别是发现盗链比较多的时候，这个时候，可以让任何盗链的网站帮我们免费宣传~~~那就是把盗链的url重定向到我们的网站宣传页~~<br />
    建立脚本：/usr/local/squid/libexec/squid_redir.pl<br />
&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8211;<br />
#!/usr/bin/perl -T -w<br />
#<br />
# rredir.pl<br />
#<br />
# Author: Peter Eisenhauer
<pe@pipetronix.de>
# First Version: 26. May 1997<br />
# Modified by oknet http://blog.sina.com.cn/m/oknet<br />
#<br />
# Description: Direct all request to files who are in a local dir to<br />
# this directory<br />
#<br />
use File::Basename;<br />
use URI::URL;<br />
# flush after every print<br />
$| = 1;<br />
# Process lines of the form &#8216;URL ip-address/fqdn ident method&#8217;<br />
# See release notes of Squid 1.1 for details<br />
while ( <> ) {<br />
    $r302=0;<br />
    ($url, $addr, $fqdn, $ident, $method) = m:(\S*) (\S*)/(\S*) (\S*) (\S*):;<br />
    $url = url $url;<br />
    $host = lc($url->host);<br />
    if ( $host !~ /\./ ) {<br />
        next;<br />
    }<br />
    if ( $host =~ /vod\.domain\.com/ ) {<br />
        $url->path(&#8220;/ad.wmv&#8221;);<br />
        $r302=1;<br />
    }<br />
} continue {<br />
    if ( $r302 ) {<br />
        print &#8220;302:$url\n&#8221;;<br />
    } else {<br />
        print &#8220;$url $addr/$fqdn $ident $method\n&#8221;;<br />
    }<br />
}<br />
&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8211;<br />
    然后在squid.conf添加：<br />
redirect_program /usr/local/squid/libexec/squid_redir.pl<br />
redirect_children 5<br />
acl superurl url_regex -i ^http://vod\.domain\.com/tom\.wmv$<br />
redirector_access deny superurl<br />
redirector_access allow filetype !dl<br />
redirector_access deny all<br />
    设置superurl是因为宣传我们自己站点的视频是不做防盗链的，这样才能起到宣传的作用。现在大功告成啦！网站的流量大幅增加~~~PV是原来的三倍，Oh，Yeah~</p>
<p>    WMS视频的MMS协议由于不是明文，无法实现防盗链，但是RTSP协议基本就是HTTP协议的变种，可以在BIGIP等可以进行Layer 7处理数据的设备上实现对Cookie的校验。但是WMS视频防盗链要禁止MMS协议，因为MMS协议不是明文，无法进行cookies的识别。但是可以在HTTP，RTSP上进行识别，WMS V9都是支持HTTP，RTSP的。下面是用于BIGIP的防盗链iRule:<br />
&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8211;<br />
if (http_uri matches_regex &#8220;vod.domain.com&#8221;) {<br />
   if (http_cookie(&#8220;Cache&#8221;) == &#8220;vod&#8221;) {<br />
      use pool vod-rtsp<br />
   }<br />
   else {<br />
      discard<br />
   }<br />
}<br />
else {<br />
   use pool vod-rtsp<br />
}<br />
&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8211;<br />
    其他的系统可以参考以上的规则。<br />
    采用Cookie的防盗链方式对于大多数的系统都可以轻易实现，Cookie一般都是用来传递认证信息，相信不会出现不传递的状况。</p>
<p>转自：http://blog.sina.com.cn/s/blog_544465b00100034a.html</p>
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		</item>
		<item>
		<title>pureftpd如何刷新用户目录已使用的总容量</title>
		<link>http://226617.cn/archives/868.htm</link>
		<comments>http://226617.cn/archives/868.htm#comments</comments>
		<pubDate>Wed, 08 Sep 2010 02:36:38 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[linux相关]]></category>
		<category><![CDATA[软件相关]]></category>
		<category><![CDATA[pureftpd]]></category>
		<category><![CDATA[quota]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=868</guid>
		<description><![CDATA[今天一个部门打电话来说文件传不上ftp，看了下提示是空间满了，结果扫描了下实际容量似乎没满，感觉是quota的识别容量错了。 说实话这pureftpd用的还很少在安装目录里面逛了圈发现了pure-quot... ]]></description>
			<content:encoded><![CDATA[<p>今天一个部门打电话来说文件传不上ftp，看了下提示是空间满了，结果扫描了下实际容量似乎没满，感觉是quota的识别容量错了。<br />
说实话这pureftpd用的还很少在安装目录里面逛了圈发现了pure-quotacheck这个命令，应该就是了。<br />
试了试使用格式如下：<br />
/usr/local/pureftpd/sbin/pure-quotacheck -u www -d /www/aaa.com</p>
<p>-u 是你指定pure-quotacheck运行时以系统的什么用户去扫描<br />
-d 就是你ftp站点的目录</p>
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		<item>
		<title>一时大意竟然域名过期了都不知道</title>
		<link>http://226617.cn/archives/864.htm</link>
		<comments>http://226617.cn/archives/864.htm#comments</comments>
		<pubDate>Mon, 30 Aug 2010 15:59:47 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[只谈心情]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=864</guid>
		<description><![CDATA[今天看见篇新闻说关停未提交实名信息的cn域名开始关闭的时候想检查下自己的cn域名的，结果发现竟然过期了。。。。 以防万一如果发现226617.cn无法打开的时候可以用226617.com来访问本博... ]]></description>
			<content:encoded><![CDATA[<p>今天看见篇新闻说关停未提交实名信息的cn域名开始关闭的时候想检查下自己的cn域名的，结果发现竟然过期了。。。。<br />
以防万一如果发现226617.cn无法打开的时候可以用226617.com来访问本博客</p>
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		<item>
		<title>RHEL5/CentOS5 上支持 Ext4</title>
		<link>http://226617.cn/archives/861.htm</link>
		<comments>http://226617.cn/archives/861.htm#comments</comments>
		<pubDate>Wed, 04 Aug 2010 07:24:27 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[linux相关]]></category>
		<category><![CDATA[ext4]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=861</guid>
		<description><![CDATA[根据我以前的测试 Ext4 的性能好过 Ext3,在 RHEL5 上的 2.6.18-110 也有加入 Ext4 了。但默认没有让我们使用，怎么样才能不重起，能使用这个啦。 其实我们只要加入一个包e4fsprogs 就行，它其实和 e2fs... ]]></description>
			<content:encoded><![CDATA[<p>根据我以前的测试 Ext4 的性能好过 Ext3,在 RHEL5 上的 2.6.18-110 也有加入 Ext4 了。但默认没有让我们使用，怎么样才能不重起，能使用这个啦。<br />
其实我们只要加入一个包e4fsprogs 就行，它其实和 e2fsprogs 是一样的功能，这 RHEL-6 中，会变成一个默认的包的。所以我们目前还只能使用这个包来调整和设置Ext4.</p>
<p><code>yum -y install e4fsprogs</code></p>
<p>在 RHEL 和 Centos5 中使用 Ext4 前，很多想可能想先给现有的文件系统转换成 Ext4 ，只要运行下面的命令就行了</p>
<p><code>tune4fs -O extents,uninit_bg,dir_index,flex_bg /dev/sdb1</code></p>
<p> 在重起前，我还要让内核支持 Ext4 的文件系统，需要修改 initrd 的文件本身的内容。如下命令来生成 支持 Ext4 的 initrd。</p>
<p><code>mkinitrd --with=ext4 --with=ext3 -f /boot/initrd-2.6.18-194.8.1.el5.img 2.6.18-194.8.1</code></p>
<p>转载自：扶凯[http://www.php-oa.com] </p>
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		<item>
		<title>php开启open_basedir后启用eaccelerator时File() on line 0报错解决</title>
		<link>http://226617.cn/archives/847.htm</link>
		<comments>http://226617.cn/archives/847.htm#comments</comments>
		<pubDate>Mon, 14 Jun 2010 05:40:26 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[linux相关]]></category>
		<category><![CDATA[php相关]]></category>
		<category><![CDATA[eaccelerator]]></category>
		<category><![CDATA[File()]]></category>
		<category><![CDATA[line 0]]></category>
		<category><![CDATA[open_basedir]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=847</guid>
		<description><![CDATA[open_basedir是php提升安全性的重要功能，eaccelerator是提速php的扩展模块，但是似乎默认环境下他们2一起用只要有require就会造成大量的php错误。 PHP Warning: Unknown: open_basedir restriction in effect. File() is ... ]]></description>
			<content:encoded><![CDATA[<p>open_basedir是php提升安全性的重要功能，eaccelerator是提速php的扩展模块，但是似乎默认环境下他们2一起用只要有require就会造成大量的php错误。</p>
<p><code><br />
PHP Warning:  Unknown: open_basedir restriction in effect. File() is not within the allowed path(s): (/www/:/tmp/) in Unknown on line 0<br />
</code></p>
<p>要解决这个问题的话在编译eaccelerator时 加上一个参数就行 &#8211;without-eaccelerator-use-inode<br />
官方也说将在0.9.6.1的下一个release中默认启用这个参数。</p>
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		<item>
		<title>由nginx漏洞想到的禁止某个目录执行php权限</title>
		<link>http://226617.cn/archives/839.htm</link>
		<comments>http://226617.cn/archives/839.htm#comments</comments>
		<pubDate>Sat, 22 May 2010 07:13:12 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[nginx相关]]></category>
		<category><![CDATA[location]]></category>
		<category><![CDATA[nginx]]></category>
		<category><![CDATA[php]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=839</guid>
		<description><![CDATA[这次的nginx漏洞可谓是惊天，具体就不说了，详情见 http://www.80sec.com/nginx-securit.html 这漏洞可怕之处就是一旦有用户可以上传的地方如果能把php改后缀方式上传到服务器的话，就能任意执行。 其... ]]></description>
			<content:encoded><![CDATA[<p>这次的nginx漏洞可谓是惊天，具体就不说了，详情见 http://www.80sec.com/nginx-securit.html<br />
这漏洞可怕之处就是一旦有用户可以上传的地方如果能把php改后缀方式上传到服务器的话，就能任意执行。<br />
其实有一个通用的方法可以来避免这种未知漏洞，就是禁止用户上传目录执行php权限。<br />
在apache下面我们可以通过：</p>

<div class="wp_syntax"><table><tr><td class="line_numbers"><pre>1
2
3
</pre></td><td class="code"><pre class="apache" style="font-family:monospace;">   &lt;<span style="color: #000000; font-weight:bold;">Directory</span> /website/attachments&gt;
        <span style="color: #00007f;">php_flag</span> engine <span style="color: #0000ff;">off</span>
   &lt;/<span style="color: #000000; font-weight:bold;">Directory</span>&gt;</pre></td></tr></table></div>

<p>的方式来来禁用目录下文件php执行权限。<br />
那么在nginx里面同样可以实现这种方法，那就是location的优先匹配，关于location可以参考我之前的一批文章http://226617.cn/archives/392.htm<br />
这里简单就举个例子</p>

<div class="wp_syntax"><table><tr><td class="line_numbers"><pre>1
2
3
4
</pre></td><td class="code"><pre class="nginx" style="font-family:monospace;">   location ^~ /attachments/
   {
      access_log  off;
   }</pre></td></tr></table></div>

<p>这样 attachments这个目录 就不会再去跳转给fastcgi去执行php了</p>
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		</item>
		<item>
		<title>linux下如何在一台机器上安装多个mysql实例</title>
		<link>http://226617.cn/archives/828.htm</link>
		<comments>http://226617.cn/archives/828.htm#comments</comments>
		<pubDate>Mon, 26 Apr 2010 17:14:31 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[linux相关]]></category>
		<category><![CDATA[mysql相关]]></category>
		<category><![CDATA[php相关]]></category>
		<category><![CDATA[只谈技术]]></category>
		<category><![CDATA[linux]]></category>
		<category><![CDATA[mysql]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=828</guid>
		<description><![CDATA[最近再做个mysql一从多主的配置，需要在一台机器上安装多个mysql。 起先是按照复制了多了mysql 同时起，在琢磨如何做启动脚本的时候发现support-files目录下有个mysqld_multi.server文件，一查发现原... ]]></description>
			<content:encoded><![CDATA[<p>最近再做个mysql一从多主的配置，需要在一台机器上安装多个mysql。<br />
起先是按照复制了多了mysql 同时起，在琢磨如何做启动脚本的时候发现support-files目录下有个mysqld_multi.server文件，一查发现原来是现成的多实例管理工具。<br />
首先得新建个data目录给新的实例，可以把原来的data目录复制个新的 只需要mysql库，也可以用工具部属个</p>

<div class="wp_syntax"><table><tr><td class="line_numbers"><pre>1
</pre></td><td class="code"><pre class="shell" style="font-family:monospace;">./scripts/mysql_install_db --basedir=/usr/local/mysql3307 --datadir=/mysql/mysql3307/data --user=mysql</pre></td></tr></table></div>

<p>然后修改下my.cnf<br />
主要增加</p>

<div class="wp_syntax"><table><tr><td class="line_numbers"><pre>1
2
3
4
5
6
</pre></td><td class="code"><pre class="mysql" style="font-family:monospace;"><span style="color: #FF00FF;">&#91;</span>mysqld_multi<span style="color: #FF00FF;">&#93;</span>
mysqld <span style="color: #CC0099;">=</span> <span style="color: #CC0099;">/</span>usr<span style="color: #CC0099;">/</span><span style="color: #990099; font-weight: bold;">local</span><span style="color: #CC0099;">/</span>mysql<span style="color: #CC0099;">/</span><span style="color: #000099;">bin</span><span style="color: #CC0099;">/</span>mysqld_safe
mysqladmin <span style="color: #CC0099;">=</span> <span style="color: #CC0099;">/</span>usr<span style="color: #CC0099;">/</span><span style="color: #990099; font-weight: bold;">local</span><span style="color: #CC0099;">/</span>mysql<span style="color: #CC0099;">/</span><span style="color: #000099;">bin</span><span style="color: #CC0099;">/</span>mysqladmin
<span style="color: #000099;">user</span> <span style="color: #CC0099;">=</span> shutdown
<span style="color: #000099;">password</span> <span style="color: #CC0099;">=</span> <span style="color: #008080;">123456</span>
<span style="color: #000099;">log</span> <span style="color: #CC0099;">=</span> <span style="color: #CC0099;">/</span>mysql<span style="color: #CC0099;">/</span>mysqld_multi.<span style="color: #000099;">log</span></pre></td></tr></table></div>

<p>然后把原来的 [mysqld] 改为 [mysqld1]<br />
在新增新的实例配置</p>

<div class="wp_syntax"><table><tr><td class="line_numbers"><pre>1
2
3
4
5
6
</pre></td><td class="code"><pre class="mysql" style="font-family:monospace;"><span style="color: #FF00FF;">&#91;</span>mysqld2<span style="color: #FF00FF;">&#93;</span>
port <span style="color: #CC0099;">=</span> <span style="color: #008080;">3307</span>
socket <span style="color: #CC0099;">=</span> <span style="color: #CC0099;">/</span>tmp<span style="color: #CC0099;">/</span>mysql3307.sock
datadir <span style="color: #CC0099;">=</span> <span style="color: #CC0099;">/</span>storage<span style="color: #CC0099;">/</span>mysql<span style="color: #CC0099;">/</span>data3307
............
............</pre></td></tr></table></div>

<p>然后把 mysqld_multi.server 做成启动服务</p>

<div class="wp_syntax"><table><tr><td class="line_numbers"><pre>1
2
3
4
5
6
</pre></td><td class="code"><pre class="shell" style="font-family:monospace;">cp ./support-files/mysqld_multi.server /etc/rc.d/init.d/mysqld
chown root:root /etc/rc.d/init.d/mysqld
chmod 755 /etc/rc.d/init.d/mysqld
chkconfig --add mysqld
chkconfig --level 3 mysqld on
chkconfig --level 5 mysqld on</pre></td></tr></table></div>

<p>启动和关闭全部mysql实例<br />
启动：service mysqld start<br />
关闭：service mysqld stop</p>
<p>对单台数据库的启动和关闭<br />
启动： service mysqld start 1<br />
关闭： service mysqld stop 1</p>
<p>也可以同时启动和关闭多个数据库实例<br />
启动： service mysqld start 1-2<br />
关闭： service mysqld stop 1-2</p>
<p>如果启动的时候提示出错信息：<br />
WARNING: my_print_defaults command not found.<br />
Please make sure you have this command available and<br />
in your path. The command is available from the latest<br />
MySQL distribution.<br />
ABORT: Can&#8217;t find command &#8216;my_print_defaults&#8217;.<br />
This command is available from the latest MySQL<br />
distribution. Please make sure you have the command<br />
in your PATH.</p>
<p>先添加<br />
export PATH=/usr/local/mysql/bin:$PATH<br />
然后在启动mysql</p>
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		</item>
		<item>
		<title>克隆VirtualBox的虚拟机</title>
		<link>http://226617.cn/archives/820.htm</link>
		<comments>http://226617.cn/archives/820.htm#comments</comments>
		<pubDate>Mon, 25 Jan 2010 14:54:56 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[只谈技术]]></category>
		<category><![CDATA[软件相关]]></category>
		<category><![CDATA[vdi]]></category>
		<category><![CDATA[VirtualBox]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=820</guid>
		<description><![CDATA[VirtualBox的虚拟机克隆主要就是克隆一份vdi文件，今天在克隆一台VirtualBox的虚拟机时以为和vmware那样复制粘贴注册vdi的时候会提示copy it之类的，没想到直接报错uuid重复注册。翻了下帮助原来Virt... ]]></description>
			<content:encoded><![CDATA[<p>VirtualBox的虚拟机克隆主要就是克隆一份vdi文件，今天在克隆一台VirtualBox的虚拟机时以为和vmware那样复制粘贴注册vdi的时候会提示copy it之类的，没想到直接报错uuid重复注册。翻了下帮助原来VirtualBox有转码的工具来进行vdi克隆。<br />
在VirtualBox的安装目录下有个 VBoxManage.exe 其实这工具有蛮多功能，有兴趣的同学可以自己看看帮助。我们这里就说下如何克隆vdi了：<br />
VBoxManage.exe clonevdi 原始VDI文件名 新的VDI文件名<br />
其实蛮方便的一个工具想不懂为啥不做成图形的非得要敲命令呢，用户体验真差。</p>
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		</item>
		<item>
		<title>linux执行脚本提示: No such file or directory</title>
		<link>http://226617.cn/archives/817.htm</link>
		<comments>http://226617.cn/archives/817.htm#comments</comments>
		<pubDate>Thu, 31 Dec 2009 15:53:11 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[linux相关]]></category>
		<category><![CDATA[linux]]></category>
		<category><![CDATA[脚本]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=817</guid>
		<description><![CDATA[今天在装sphinx，收尾准备做个增量的脚本放crontab里面去，结果每次执行都是提示: No such file or directory。搞来搞去最后发现文本格式忘了改成unix的了，... ]]></description>
			<content:encoded><![CDATA[<p>今天在装sphinx，收尾准备做个增量的脚本放crontab里面去，结果每次执行都是提示: No such file or directory。搞来搞去最后发现文本格式忘了改成unix的了，汗</p>
]]></content:encoded>
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		</item>
		<item>
		<title>VC克隆虚拟机提示虚拟机文件损坏一例</title>
		<link>http://226617.cn/archives/815.htm</link>
		<comments>http://226617.cn/archives/815.htm#comments</comments>
		<pubDate>Fri, 20 Nov 2009 07:47:10 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[vmware相关]]></category>
		<category><![CDATA[只谈技术]]></category>
		<category><![CDATA[uuid]]></category>
		<category><![CDATA[vmware]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=815</guid>
		<description><![CDATA[今天在准备部署一台新的虚拟机，把模板机更新了下补丁，装了新的vmtools，克隆的时候再快结束的时候提示虚拟机文件损坏。由于模板机能正常开机运行，虚拟机内操作也很正常，所以觉得和v... ]]></description>
			<content:encoded><![CDATA[<p>今天在准备部署一台新的虚拟机，把模板机更新了下补丁，装了新的vmtools，克隆的时候再快结束的时候提示虚拟机文件损坏。由于模板机能正常开机运行，虚拟机内操作也很正常，所以觉得和vmdk文件没什么关系，而且克隆的时候vmdk也是克隆完成的，所以怀疑是vmx文件的问题，于是下载了下来仔细看了下，发现一个可疑之处 uuid.location = &#8220;&#8221; 内容竟然空白，又对比了一台正常的机器和一台刚刚克隆完的机器，证实确实是uuid.location问题，把uuid.location = &#8220;&#8221; 这行删除掉，上传上esx，重新启动模板机后就自动生成了。然后克隆成功，问题解决。</p>
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		</item>
		<item>
		<title>EditPlus正则替换一例</title>
		<link>http://226617.cn/archives/812.htm</link>
		<comments>http://226617.cn/archives/812.htm#comments</comments>
		<pubDate>Wed, 18 Nov 2009 07:59:59 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[只谈技术]]></category>
		<category><![CDATA[软件相关]]></category>
		<category><![CDATA[EditPlus]]></category>
		<category><![CDATA[正则表达式]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=812</guid>
		<description><![CDATA[有个mysql的查询 用的 where xxx in ('a','b','c','d')，现在有一批数据需要放入in () 来查询，在想如何批量转换成'a','b','c','d' 这样的格式。 首先我把数据处理成每行1个的格式： a b c d 这样 通过EditPlus... ]]></description>
			<content:encoded><![CDATA[<p><code>有个mysql的查询 用的 where xxx in ('a','b','c','d')，现在有一批数据需要放入in () 来查询，在想如何批量转换成'a','b','c','d' 这样的格式。<br />
首先我把数据处理成每行1个的格式：<br />
a<br />
b<br />
c<br />
d<br />
这样<br />
通过EditPlus的正则替换功能，查找^.* 替换为 '\0' 得到<br />
'a'<br />
'b'<br />
'c'<br />
'd'<br />
然后在通过正则替换，查找 \n 替换为 , 就得到了<br />
'a','b','c','d'<br />
达到目标</code></p>
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		</item>
		<item>
		<title>ESX正常VC里连接不上解决办法</title>
		<link>http://226617.cn/archives/809.htm</link>
		<comments>http://226617.cn/archives/809.htm#comments</comments>
		<pubDate>Tue, 17 Nov 2009 13:10:56 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[vmware相关]]></category>
		<category><![CDATA[只谈技术]]></category>
		<category><![CDATA[esx]]></category>
		<category><![CDATA[vmware]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=809</guid>
		<description><![CDATA[今天忽然发现VC里某台ESX里面的虚拟机全部无法控制，列表里面CPU和内存信息都是0，显然这台ESX出问题了，尝试断开并重新连接这台ESX结果连接失败，弹出输入用户名和密码，填写后还是连接... ]]></description>
			<content:encoded><![CDATA[<p>今天忽然发现VC里某台ESX里面的虚拟机全部无法控制，列表里面CPU和内存信息都是0，显然这台ESX出问题了，尝试断开并重新连接这台ESX结果连接失败，弹出输入用户名和密码，填写后还是连接不上，尝试ping这台esx主机发现ping的通，直接登录到esx的console发现能登陆，检查服务也正常。看来是esx的问题了，打算重启下，可以里面有2台比较重要的虚拟机，直接重启ESX担心会造成影响，所以尝试的重启部分服务，结果service mgmt-vmware restart后正常了。</p>
<p>一般情况下出现esx和vc的连接问题除了重启上面的mgmt-vmware外还可以service vmware-vpxa restart重启下vpxa，说不定就能解决</p>
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		</item>
		<item>
		<title>Nginx+keepalived负载均衡篇</title>
		<link>http://226617.cn/archives/791.htm</link>
		<comments>http://226617.cn/archives/791.htm#comments</comments>
		<pubDate>Fri, 06 Nov 2009 13:17:06 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[linux相关]]></category>
		<category><![CDATA[nginx相关]]></category>
		<category><![CDATA[keepalived]]></category>
		<category><![CDATA[nginx]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=791</guid>
		<description><![CDATA[由于nginx的url hash功能可以很好的提升squid的性能，所以我把squid前端的负载均衡器更换为nginx，但是一台nginx就形成了单点，现在使用keepalived来解决这个问题，keepalived的故障转移时间很短... ]]></description>
			<content:encoded><![CDATA[<p>由于nginx的url hash功能可以很好的提升squid的性能，所以我把squid前端的负载均衡器更换为nginx，但是一台nginx就形成了单点，现在使用keepalived来解决这个问题，keepalived的故障转移时间很短(<1s)，而且配置简单，这也是选择keepalived的一个主要原因，建议日PV值小的中小型企业web均可采用如下方案实行，下面直接上安装步骤：</p>
<p>一、环境：<br />
centos5.3、nginx-0.7.51、keepalived-1.1.19<br />
主nginx负载均衡器：192.168.0.154<br />
辅nginx负载均衡器：192.168.9.155<br />
vip：192.168.0.188</p>
<p>二、安装keepalived</p>
<p>#tar zxvf keepalived-1.1.19.tar.gz<br />
#cd keepalived-1.1.19<br />
#./configure --prefix=/usr/local/keepalived<br />
#make<br />
#make install<br />
#cp /usr/local/keepalived/sbin/keepalived /usr/sbin/<br />
#cp /usr/local/keepalived/etc/sysconfig/keepalived /etc/sysconfig/<br />
#cp /usr/local/keepalived/etc/rc.d/init.d/keepalived /etc/init.d/<br />
#mkdir /etc/keepalived<br />
#cd /etc/keepalived/<br />
vim keepalived.conf</p>
<p>! Configuration File for keepalived<br />
global_defs {<br />
   notification_email {<br />
   yuhongchun027@163.com<br />
        }<br />
   notification_email_from keepalived@chtopnet.com<br />
   smtp_server 127.0.0.1<br />
   smtp_connect_timeout 30<br />
   router_id LVS_DEVEL<br />
}</p>
<p>vrrp_instance VI_1 {<br />
    state MASTER<br />
    interface eth0<br />
    virtual_router_id 51<br />
    mcast_src_ip 192.168.0.155    <==辅nginx的IP地址<br />
    priority 100<br />
    advert_int 1<br />
    authentication {<br />
        auth_type PASS<br />
        auth_pass chtopnet<br />
    }<br />
    virtual_ipaddress {<br />
        192.168.0.188                      <==vip地址<br />
    }<br />
}<br />
#service keepalived start<br />
我们来看一下日志：<br />
[root@ltos ~]# tail /var/log/messages<br />
Oct 6 03:25:03 ltos avahi-daemon[2306]: Registering new address record for 192.168.0.188 on eth0.<br />
Oct 6 03:25:03 ltos avahi-daemon[2306]: Registering new address record for 192.168.0.154 on eth0.<br />
Oct 6 03:25:03 ltos avahi-daemon[2306]: Registering HINFO record with values 'I686'/'LINUX'.<br />
Oct 6 03:25:23 ltos avahi-daemon[2306]: Withdrawing address record for fe80::20c:29ff:feb9:eeab on eth0.<br />
Oct 6 03:25:23 ltos avahi-daemon[2306]: Withdrawing address record for 192.168.0.154 on eth0.<br />
Oct 6 03:25:23 ltos avahi-daemon[2306]: Host name conflict, retrying with <ltos-31><br />
Oct 6 03:25:23 ltos avahi-daemon[2306]: Registering new address record for fe80::20c:29ff:feb9:eeab on eth0.<br />
Oct 6 03:25:23 ltos avahi-daemon[2306]: Registering new address record for 192.168.0.188 on eth0.<br />
Oct 6 03:25:23 ltos avahi-daemon[2306]: Registering new address record for 192.168.0.154 on eth0.<br />
Oct 6 03:25:23 ltos avahi-daemon[2306]: Registering HINFO record with values &#8216;I686&#8242;/&#8217;LINUX&#8217;.</p>
<p>很显然vrrp已经启动，我们还可以通过命令：#ip a 来检查</p>
<p>[root@ltos html]# ip a<br />
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue<br />
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00<br />
    inet 127.0.0.1/8 scope host lo<br />
    inet6 ::1/128 scope host<br />
       valid_lft forever preferred_lft forever<br />
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast qlen 1000<br />
    link/ether 00:0c:29:ba:9b:e7 brd ff:ff:ff:ff:ff:ff<br />
    inet 192.168.0.154/24 brd 192.168.0.255 scope global eth0<br />
    inet 192.168.0.188/32 scope global eth0<br />
    inet6 fe80::20c:29ff:feba:9be7/64 scope link<br />
       valid_lft forever preferred_lft forever<br />
3: sit0: <NOARP> mtu 1480 qdisc noop<br />
    link/sit 0.0.0.0 brd 0.0.0.0</p>
<p>说明vip已经启动，这样主服务器就配置好了，辅机的配置大致一样，除了配置文件有少部分的变化，下</p>
<p>面贴出辅机的配置文件：</p>
<p>! Configuration File for keepalived<br />
global_defs {<br />
   notification_email {<br />
   yuhongchun027@163.com<br />
        }<br />
   notification_email_from keepalived@chtopnet.com<br />
   smtp_server 127.0.0.1<br />
   smtp_connect_timeout 30<br />
   router_id LVS_DEVEL<br />
}</p>
<p>vrrp_instance VI_1 {<br />
    state BACKUP<br />
    interface eth0<br />
    virtual_router_id 51<br />
    mcast_src_ip 192.168.0.154              <==主nginx的IP的地址<br />
    priority 100<br />
    advert_int 1<br />
    authentication {<br />
        auth_type PASS<br />
        auth_pass chtopnet<br />
    }<br />
    virtual_ipaddress {<br />
        192.168.0.188<br />
    }<br />
}</p>
<p>检查其配置<br />
[root@ltos html]# ip a<br />
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue<br />
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00<br />
    inet 127.0.0.1/8 scope host lo<br />
    inet6 ::1/128 scope host<br />
       valid_lft forever preferred_lft forever<br />
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast qlen 1000<br />
    link/ether 00:0c:29:ba:9b:e7 brd ff:ff:ff:ff:ff:ff<br />
    inet 192.168.0.155/24 brd 192.168.0.255 scope global eth0<br />
    inet 192.168.0.188/32 scope global eth0<br />
    inet6 fe80::20c:29ff:feba:9be7/64 scope link<br />
       valid_lft forever preferred_lft forever<br />
3: sit0: <NOARP> mtu 1480 qdisc noop<br />
    link/sit 0.0.0.0 brd 0.0.0.0</p>
<p>测试其效果方法很简单，分别在主辅机上建立不同的主页，index.html分别为192.168.0.154,192.168.0.155，然后用客户机上elinks http://192.168.0.188,主机down掉后辅机会马上接替提供服务，间隔时间几乎无法感觉出来,这个环境准备再进行下压力测试，用于我杭州网跃朋友的web服务器，如有疑问请联系yuhongchun027@163.com(抚琴煮酒)</p>
<p>转载至 http://hi.baidu.com/yuhongchun027/blog/item/25eca12c3442e9e68a13998c.html</p>
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		</item>
		<item>
		<title>从根服务器查询域名的ns记录</title>
		<link>http://226617.cn/archives/786.htm</link>
		<comments>http://226617.cn/archives/786.htm#comments</comments>
		<pubDate>Tue, 22 Sep 2009 16:01:18 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[软件相关]]></category>
		<category><![CDATA[dns]]></category>
		<category><![CDATA[nslookup]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=786</guid>
		<description><![CDATA[有时候更新域名的域名服务器，需要查看是否生效，只能通过根服务器的NS查询来辨别。可以使用下面的命令 nslookup -qt=ns thmz.com a.gtld-servers.net 如果根服务器已经更新的话再对比运营商的dns看看... ]]></description>
			<content:encoded><![CDATA[<p>有时候更新域名的域名服务器，需要查看是否生效，只能通过根服务器的NS查询来辨别。可以使用下面的命令<br />
nslookup -qt=ns thmz.com a.gtld-servers.net<br />
如果根服务器已经更新的话再对比运营商的dns看看有没有更新<br />
nslookup -qt=ns thmz.com</p>
<p>再或者 nslookup -d thmz.com 自己看看各个节点的过期时间</p>
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		</item>
		<item>
		<title>bind的top，dnstop安装使用教程</title>
		<link>http://226617.cn/archives/782.htm</link>
		<comments>http://226617.cn/archives/782.htm#comments</comments>
		<pubDate>Tue, 22 Sep 2009 15:08:39 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[linux相关]]></category>
		<category><![CDATA[软件相关]]></category>
		<category><![CDATA[bind]]></category>
		<category><![CDATA[dnstop]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=782</guid>
		<description><![CDATA[安装这里以centos为例 yum install libpcap libpcap-devel ncurses-devel ncurses wget http://dns.measurement-factory.com/tools/dnstop/src/dnstop-20090128.tar.gz tar zxvf dnstop-20090128.tar.gz cd dnstop-20090128 ./configure make &#038;&#038; make inst... ]]></description>
			<content:encoded><![CDATA[<p>安装这里以centos为例</p>
<p>yum install libpcap libpcap-devel ncurses-devel ncurses<br />
wget http://dns.measurement-factory.com/tools/dnstop/src/dnstop-20090128.tar.gz<br />
tar zxvf dnstop-20090128.tar.gz<br />
cd dnstop-20090128<br />
./configure<br />
make &#038;&#038; make install</p>
<p>使用方法很简单 dnstop eth0<br />
输入? 可以看到详细帮助，这里不多介绍了。</p>
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		<item>
		<title>用diskpart扩展windows磁盘空间</title>
		<link>http://226617.cn/archives/780.htm</link>
		<comments>http://226617.cn/archives/780.htm#comments</comments>
		<pubDate>Sun, 20 Sep 2009 15:29:22 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[windows相关]]></category>
		<category><![CDATA[diskpart]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=780</guid>
		<description><![CDATA[Diskpart.exe 实用程序在命令行界面中管理磁盘、分区和卷。Diskpart.exe 在基本磁盘和动态磁盘上都可以使用。如果 NTFS 卷所在的硬件 RAID 5 容器具有向容器中添加空间的能力，您可以使用 Diskpart.exe... ]]></description>
			<content:encoded><![CDATA[<p>Diskpart.exe 实用程序在命令行界面中管理磁盘、分区和卷。Diskpart.exe 在基本磁盘和动态磁盘上都可以使用。如果 NTFS 卷所在的硬件 RAID 5 容器具有向容器中添加空间的能力，您可以使用 Diskpart.exe 扩展 NTFS 卷，同时将磁盘保持为基本磁盘。</p>
<p>使用 extend 命令可以在保留数据的同时将未分配的空间合并到现有卷中。</p>
<p>下面是对 extend 命令的要求： • 卷必须用 NTFS 文件系统格式化。</p>
<p>• 对于基本卷，扩展的未分配空间必须是同一磁盘上的下一个相邻空间。<br />
• 对于动态卷，未分配空间可以是系统上任何动态磁盘上的空白空间。<br />
• 只支持数据卷扩展。系统卷或启动卷无法扩展，若扩展它们可能会收到以下错误消息：</p>
<p>DiskPart 未能扩展卷。请确定卷是有效的，可以扩展</p>
<p>• 如果系统页面文件在此分区，您就不能扩展该分区。请将系统页面文件移动到一个不希望扩展的分区。</p>
<p>要扩展分区或卷，必须先选择该卷以将焦点移到该卷，然后可以指定扩展的大小。要扩展卷，请按照以下步骤操作：</p>
<p>1. 在命令提示符下，键入 diskpart.exe。<br />
2. 键入 list volume 以显示计算机上的现有卷。<br />
3. 键入 Select volume volume number，其中 volume number 是要扩展的卷的编号。<br />
4. 键入 extend [size=n] [disk=n] [noerr]。</p>
<p>下面将介绍这些参数：</p>
<p>size=n</p>
<p>要向当前分区添加的空间大小（以 MB 为单位）。如果您没有指定大小，磁盘将一直扩展到全部占用下一个相邻的未分配空间。</p>
<p>disk=n</p>
<p>在其上扩展卷的动态磁盘。将在该磁盘上分配“size=n”的空间。如果没有指定磁盘，则在当前磁盘上扩展卷。</p>
<p>noerr</p>
<p>仅用于脚本撰写。当发生错误时，此参数指定 Diskpart 继续处理命令，就像没有发生错误一样。如果没有指定 noerr 参数，错误将导致 Diskpart 退出并显示错误代码。</p>
<p>5. 键入 exit 退出 Diskpart.exe。</p>
<p>当 extend 命令完成时，您应该收到一则消息，说明 Diskpart 已成功扩展卷。新的空间应该已添加到现有驱动器，同时保留卷上的数据。</p>
<p>注意：在 Microsoft Windows XP 和 Microsoft Windows 2000 中，不能使用 Diskpart.exe 扩展动态磁盘上的最初在基本磁盘上创建的简单卷。只能扩展磁盘升级到动态磁盘后创建的简单卷。如果您试图扩展动态磁盘上的最初在基本磁盘上创建的简单卷，将收到以下错误消息。该限制已在 Microsoft Windows Server 2003 中去除。</p>
<p>DiskPart 未能扩展卷。<br />
请确定卷是有效的，可以扩展</p>
<p>注意：Windows Server 2003 和 Windows XP 中包含 Diskpart.exe，并将其作为基本操作系统的一部分。</p>
<p>要下载用于 Windows 2000 的 Diskpart.exe 命令行实用程序，请访问以下 Microsoft 网站：</p>
<p>http://www.microsoft.com/downloads/details.aspx?FamilyID=0fd9788a-5d64-4f57-949f-ef62de7ab1ae&#038;displaylang=en</p>
<p>注意：我们建议您在转换为动态磁盘之前，联系您的系统供应商以获得更新的 BIOS、固件、驱动程序和代理程序。</p>
<p>&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8211;</p>
<p>这篇文章中的信息适用于:</p>
<p>• Microsoft Windows Server 2003 Standard Edition<br />
• Microsoft Windows Server 2003 Web Edition<br />
• Microsoft Windows Server 2003 Enterprise Edition<br />
• Microsoft Windows Server 2003, Enterprise Edition for Itanium-based Systems<br />
• Microsoft Windows XP Home Edition<br />
• Microsoft Windows XP Professional Edition<br />
• Microsoft Windows 2000 Server<br />
• Microsoft Windows 2000 Advanced Server<br />
• Microsoft Windows 2000 Professional Edition</p>
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		<item>
		<title>微软补丁KB967723造成MySQL频繁无法连接</title>
		<link>http://226617.cn/archives/778.htm</link>
		<comments>http://226617.cn/archives/778.htm#comments</comments>
		<pubDate>Sat, 19 Sep 2009 14:53:44 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[mysql相关]]></category>
		<category><![CDATA[windows相关]]></category>
		<category><![CDATA[KB967723]]></category>
		<category><![CDATA[mysql]]></category>
		<category><![CDATA[补丁]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=778</guid>
		<description><![CDATA[两种解决方法： 第一种：卸载KB967723补丁 登录服务器，进入控制面板 — 添加和删除程序 — （勾选上方的“显示更新”）在里面可以看到更新的KB967723这个补丁，然后就想卸载普通软件一样卸... ]]></description>
			<content:encoded><![CDATA[<p>两种解决方法：</p>
<p>第一种：卸载KB967723补丁<br />
登录服务器，进入控制面板 — 添加和删除程序 — （勾选上方的“显示更新”）在里面可以看到更新的KB967723这个补丁，然后就想卸载普通软件一样卸载，卸载中会提示你，如果卸载可能导致程序运行出错，没关系，选择“是”，继续卸载。卸载完成后重启数据库服务器。</p>
<p>第二种：修改注册表<br />
本方法是微软给出的修改注册表修复该Bug的的方法，默认最大的临时 TCP 端口的数是 5000 适用于一节中包含的产品中。 在这些产品中添加一个新参数。 要提高临时端口的上限，请按照下列步骤操作：</p>
<p>   1. 启动注册表编辑器。<br />
   2. 在的注册表中找到以下子项，然后单击 参数 ：<br />
      HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters<br />
   3. 在 编辑 菜单上单击 新建 ，，，然后添加下面的注册表项：<br />
      数值名称： MaxUserPort<br />
      值类型: DWORD<br />
      值数据： 65534<br />
      有效范围： 5000-65534 (十进制)<br />
      默认值： 0&#215;1388 (5000 十进制)<br />
      说明： 此参数将控制程序从系统请求任何可用的用户端口时使用的最大端口数。 通常，1024 的值和包含的 5000 之间分配临时的 （短) 端口。<br />
   4. 退出注册表编辑器，并重新启动计算机。 </p>
<p>请注意 其他的 TCPTimedWaitDelay 注册表参数确定在多长时间关闭的端口等可重复使用已关闭的端口。</p>
<p>微软原文链接：http://support.microsoft.com/kb/q196271</p>
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		<item>
		<title>来自sheaven彩信帖</title>
		<link>http://226617.cn/archives/777.htm</link>
		<comments>http://226617.cn/archives/777.htm#comments</comments>
		<pubDate>Fri, 18 Sep 2009 05:31:45 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[只谈技术]]></category>

		<guid isPermaLink="false">http://226617.cn/archives/777.htm</guid>
		<description><![CDATA[蠡湖之... ]]></description>
			<content:encoded><![CDATA[<p>蠡湖之星</p>
<p><img alt="" src="http://226617.cache.i9p.com/2009/09/18/43b3d570d7d8bc0ba437dd0fc33964b1.jpeg" class="aligncenter" /></p>
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		<title>nginx 防盗链一则</title>
		<link>http://226617.cn/archives/774.htm</link>
		<comments>http://226617.cn/archives/774.htm#comments</comments>
		<pubDate>Mon, 14 Sep 2009 13:33:33 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[nginx相关]]></category>
		<category><![CDATA[nginx]]></category>
		<category><![CDATA[防盗链]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=774</guid>
		<description><![CDATA[1 2 3 4 5 6 7 location ~* ^.+\.(gif&#124;jpg&#124;png&#124;swf&#124;flv&#124;mp3&#124;zip&#124;rar)$ { valid_referers none blocked server_names *.sitea.com *.siteb.com; if ($invalid_referer) { rewrite ^/ http://www.site.com/; #return 404; } } 可以自... ]]></description>
			<content:encoded><![CDATA[
<div class="wp_syntax"><table><tr><td class="line_numbers"><pre>1
2
3
4
5
6
7
</pre></td><td class="code"><pre class="nginx" style="font-family:monospace;">location ~* ^.+\.(gif|jpg|png|swf|flv|mp3|zip|rar)$ {
        valid_referers none blocked server_names  *.sitea.com *.siteb.com;
        if ($invalid_referer) {
            rewrite ^/   http://www.site.com/;
            #return 404;
        }
    }</pre></td></tr></table></div>

<p>可以自己注释选择是返回rewrite，或者404</p>
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		<title>windows 7启动分区恢复</title>
		<link>http://226617.cn/archives/772.htm</link>
		<comments>http://226617.cn/archives/772.htm#comments</comments>
		<pubDate>Sun, 13 Sep 2009 05:24:04 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[windows相关]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=772</guid>
		<description><![CDATA[在默认安装的情况下windows 7会自动创建一个100m的启动分区，用了存放启动相关的文件。 在某些情况下比如用了软件bios模拟方式激活失败，有可能会导致无法引导windows的情况，碰到这种情况的... ]]></description>
			<content:encoded><![CDATA[<p>在默认安装的情况下windows 7会自动创建一个100m的启动分区，用了存放启动相关的文件。<br />
在某些情况下比如用了软件bios模拟方式激活失败，有可能会导致无法引导windows的情况，碰到这种情况的我们可以使用windows 7的安全光盘，进入修复模式，然后进入命令行模式。<br />
这个时候这个100m的启动分区应该加载为C: ，而原来windows所在分区会自动延后，可以在进入修复模式的地方看见是哪个盘符。<br />
比如启动分区为 C: ，windows分区为 E:<br />
如果需要还原启动分区到初始状态的话，可以先 format c: ，注意format需要输入卷标时无法输入中文，可以先dir /a看一下，然后用鼠标选中当前的中文卷标再按下鼠标右键就相当于复制，要粘贴的时候也只要按下鼠标右键。<br />
format完成后，可以使用下面命令来初始化启动分区<br />
bcdboot e:\windows /l zh-CN /s c:</p>
<p>命令执行后会有提示，输入exit，然后选择重启下启动，仍然进入windows 7安装光盘的修复模式，这里会自动扫描后提示需要修复启动。选择修复并重启后，启动分区就初始化好了。</p>
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		<title>关于discuz 7.0用户最后发表时间更新bug</title>
		<link>http://226617.cn/archives/769.htm</link>
		<comments>http://226617.cn/archives/769.htm#comments</comments>
		<pubDate>Fri, 11 Sep 2009 14:24:30 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[软件相关]]></category>
		<category><![CDATA[7.0]]></category>
		<category><![CDATA[bug]]></category>
		<category><![CDATA[discuz]]></category>
		<category><![CDATA[dz7]]></category>
		<category><![CDATA[lastpost]]></category>
		<category><![CDATA[最后发表]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=769</guid>
		<description><![CDATA[最近论坛在搞抢楼，有用户被判定一分钟发了50贴是机器灌水行为，我好想觉得后台设置过发帖时间限制为10秒的，也就是说1分钟最多发6贴。就自己研究了下，发现自从升级到dz7以来用户的最... ]]></description>
			<content:encoded><![CDATA[<p>最近论坛在搞抢楼，有用户被判定一分钟发了50贴是机器灌水行为，我好想觉得后台设置过发帖时间限制为10秒的，也就是说1分钟最多发6贴。就自己研究了下，发现自从升级到dz7以来用户的最后更新时间就没更新过，而发帖限制是靠 现在时间-发帖限制时间 和 最后发表时间去比对的，所以导致发帖时间限制的设置形同虚设。所以又仔细看了下更新用户最后发表时间相关代码。<br />
首先来看一段源代码代码</p>

<div class="wp_syntax"><table><tr><td class="line_numbers"><pre>1
2
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</pre></td><td class="code"><pre class="php" style="font-family:monospace;"><span style="color: #000088;">$self</span> <span style="color: #339933;">=</span> <span style="color: #000088;">$creditnotice</span> <span style="color: #339933;">&amp;&amp;</span> <span style="color: #000088;">$uidarray</span> <span style="color: #339933;">==</span> <span style="color: #000088;">$discuz_uid</span><span style="color: #339933;">;</span>
……
<span style="color: #000088;">$lastpostadd</span> <span style="color: #339933;">=</span> <span style="color: #000088;">$self</span> ? <span style="color: #0000ff;">&quot;, lastpost='<span style="color: #006699; font-weight: bold;">$timestamp</span>'&quot;</span> <span style="color: #339933;">:</span> <span style="color: #0000ff;">''</span><span style="color: #339933;">;</span>
……
……
<span style="color: #000088;">$db</span><span style="color: #339933;">-&gt;</span><span style="color: #004000;">query</span><span style="color: #009900;">&#40;</span><span style="color: #0000ff;">&quot;UPDATE <span style="color: #006699; font-weight: bold;">{$tablepre}</span>members SET posts=posts+('<span style="color: #006699; font-weight: bold;">$operator</span><span style="color: #006699; font-weight: bold;">$posts</span>') <span style="color: #006699; font-weight: bold;">$lastpostadd</span> <span style="color: #006699; font-weight: bold;">$creditsadd2</span> WHERE uid IN (<span style="color: #006699; font-weight: bold;">$uids</span>)&quot;</span><span style="color: #339933;">,</span> <span style="color: #0000ff;">'UNBUFFERED'</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">;</span></pre></td></tr></table></div>

<p>这里看到要 $self=1 才会把更新最后发表时间的 lastpost=&#8217;$timestamp&#8217; 加到update的sql里面，而$self=1的话除了判断下uid之外的话还有个参数 $creditnotice 必需也等于1才行。<br />
也就是必须要打开 dz7 后台 界面 全局里面的积分变动提示才会更新用户最后发表时间。</p>
<p>我想这应该算是个bug把</p>
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		<title>如何在windows7下面增加快速启动栏</title>
		<link>http://226617.cn/archives/767.htm</link>
		<comments>http://226617.cn/archives/767.htm#comments</comments>
		<pubDate>Thu, 10 Sep 2009 15:47:33 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[windows相关]]></category>
		<category><![CDATA[Quick Launch]]></category>
		<category><![CDATA[windows 7]]></category>
		<category><![CDATA[快速启动]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=767</guid>
		<description><![CDATA[windows7 和 vista最直接的改观恐怕就是在任务栏上了。很多老用户升级到7最不习惯的就是没有了快速启动，比如我就是我有很多程序启动是靠快速启动来解决的，本来想咬咬牙关强制习惯win7的任... ]]></description>
			<content:encoded><![CDATA[<p>windows7 和 vista最直接的改观恐怕就是在任务栏上了。很多老用户升级到7最不习惯的就是没有了快速启动，比如我就是我有很多程序启动是靠快速启动来解决的，本来想咬咬牙关强制习惯win7的任务栏，可是工具还没装一般任务栏就感觉不够用了，而且找起程序来实在不方便，所以我又琢磨了下其实windows7是可以增加任务栏中的快速启动栏的。具体步骤<br />
1.对着任务栏空白地方右键-工具栏-新增工具栏，然后地址栏直接输入C:\Users\登陆用户名\AppData\Roaming\Microsoft\Internet Explorer\Quick Launch<br />
选择好之后保存退出你就会看见任务栏上多出个Quick Launch，里面还有很多一些安装软件时增加快速启动栏启动项的软件快捷方式。<br />
2.解除任务栏锁定，把Quick Launch挪到最左面，然后对着Quick Launch前面挪动的那个竖条右键把显示标题和显示文本2个选项去掉，然后稍微调整下距离，锁定任务栏哈哈是不是快速启动栏又回来了 <img src='http://226617.cn/wp-includes/images/smilies/icon_mrgreen.gif' alt=':mrgreen:' class='wp-smiley' />  </p>
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		<title>我真不是故意的</title>
		<link>http://226617.cn/archives/765.htm</link>
		<comments>http://226617.cn/archives/765.htm#comments</comments>
		<pubDate>Wed, 09 Sep 2009 06:53:13 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[只谈心情]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=765</guid>
		<description><![CDATA[昨天看着火兔用了一段时间也蛮稳定的，功能也符合要求了就在博客上推荐了，结果今天就给和谐了。怎么我每次博客一推荐就会有悲剧发生啊。 没办法目前只能转战新浪微博了。 http://t.sina.c... ]]></description>
			<content:encoded><![CDATA[<p>昨天看着火兔用了一段时间也蛮稳定的，功能也符合要求了就在博客上推荐了，结果今天就给和谐了。怎么我每次博客一推荐就会有悲剧发生啊。</p>
<p>没办法目前只能转战新浪微博了。</p>
<p>http://t.sina.com.cn/sheaven</p>
<p>还有就是twitter了<br />
twitter：sheaven79</p>
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		</item>
		<item>
		<title>phpcws 升级到httpcws</title>
		<link>http://226617.cn/archives/761.htm</link>
		<comments>http://226617.cn/archives/761.htm#comments</comments>
		<pubDate>Tue, 08 Sep 2009 15:22:58 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[软件相关]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=761</guid>
		<description><![CDATA[非常好的一个分词系统，这下有进行了根本性结构的改变，更加适合互联网系统使用。强烈推荐，http://blog.s135.com/httpcws_v100... ]]></description>
			<content:encoded><![CDATA[<p>非常好的一个分词系统，这下有进行了根本性结构的改变，更加适合互联网系统使用。强烈推荐，<a href="http://blog.s135.com/httpcws_v100/">http://blog.s135.com/httpcws_v100/</a></p>
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		</item>
		<item>
		<title>转战火兔了，大家加我啊</title>
		<link>http://226617.cn/archives/758.htm</link>
		<comments>http://226617.cn/archives/758.htm#comments</comments>
		<pubDate>Tue, 08 Sep 2009 15:14:33 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[只谈心情]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=758</guid>
		<description><![CDATA[其实就是原来的嘀咕，改投换面整改了一下，符合某些规定 http://huotu.com/ id照旧 sheaven 点击链接加入火兔并加我为好... ]]></description>
			<content:encoded><![CDATA[<p>其实就是原来的嘀咕，改投换面整改了一下，符合某些规定</p>
<p>http://huotu.com/</p>
<p>id照旧 sheaven</p>
<p><a href="http://huotu.com/jump?aid=reg&#038;mid=sheaven&#038;type=link">点击链接加入火兔并加我为好友</a></p>
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		<item>
		<title>一次鬼异的2003蓝屏故障修复</title>
		<link>http://226617.cn/archives/755.htm</link>
		<comments>http://226617.cn/archives/755.htm#comments</comments>
		<pubDate>Sun, 06 Sep 2009 16:36:39 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[windows相关]]></category>
		<category><![CDATA[win2003]]></category>
		<category><![CDATA[蓝屏]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=755</guid>
		<description><![CDATA[情况是这样的 一台正常运行的机器dell 2950+双FCHBA卡，忽然发现只要一进系统就会自动蓝屏重启（开启故障自动重启），进入安全模式正常，在安全模式下看了下日志最早的是从0点多开始的一重... ]]></description>
			<content:encoded><![CDATA[<p>情况是这样的<br />
一台正常运行的机器dell 2950+双FCHBA卡，忽然发现只要一进系统就会自动蓝屏重启（开启故障自动重启），进入安全模式正常，在安全模式下看了下日志最早的是从0点多开始的一重启就蓝屏，可怜的一个晚上不知道重启了多少次。然后我把自动重启功能关闭，看蓝屏代码，提示有变化但大部分时候是0x0000009c（记不清了貌似是这个，反正有时候会变化），根据时间看似乎和打补丁也没什么关联，没办法只能重装，备份了数据库开始安装上次安装流程进行重装。<br />
这里用的是DELL install光盘引导的模式，重装完之后，装好HBA卡驱动，设好网络，下好360打好补丁，重启结果发现在重启最后原来应该是重启机器的地方蓝屏了。代码是0x0000007e试了好多次都是这个出错，由于印象中最后步骤是打系统补丁，所以以为是补丁引起的，但是正常运行的时候没有蓝屏出现，只有重启才有。<br />
这里又怀疑是HBA卡驱动引起的，又去QLogic官方下载了最新的stor miniport驱动更换了原来的scsi miniport驱动，并且还把微软有关miniport的2个补丁也打了下，最后还把2950能升的固件 bios全部升级了一边，还是无果，重启最后蓝屏。无奈进行干净版的重装，就是直接用2003光盘安装系统。<br />
这次下载了raid卡驱动后直接用2003光盘引导安装，把网卡驱动装好了，设置了下，重启结果蓝屏，抓狂。。。后来想想会不会是和R2有关系，所以又打算重装下不装R2系统。于是第三次重装开始用的是DELL install光盘引导方式。<br />
这次重装好之后跳过了R2的安装步骤，开始尝试，重启结果正常，改了DEP，虚拟内存等相关设置重启正常，改了网卡设置填了ip重启蓝屏，抓狂。去掉ip重启正常。啊。。。。。莫非ip有关系。。又尝试了填ip结果又蓝屏。。。。当中有次无意把另外一块没有接网线的网卡从禁用改成启用后，重启正常了。。。（我一直习惯把不用的网卡禁用的）又反复测试了一下，确定为只要填ip就不能禁用另外一块不用网卡，否则重启最后一步就0x0000007e蓝屏。郁闷搞了3天。。。<br />
只是非常奇怪以前的系统也是这样的但是从来没蓝屏过，这种2950的机器我装了好多台，还有一台一摸一样的也是这样禁用网卡的方式使用中也没这种蓝屏状况。</p>
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		<item>
		<title>phpmaker数据库中文乱码问题解决</title>
		<link>http://226617.cn/archives/753.htm</link>
		<comments>http://226617.cn/archives/753.htm#comments</comments>
		<pubDate>Sat, 05 Sep 2009 06:16:54 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[软件相关]]></category>
		<category><![CDATA[phpmaker]]></category>
		<category><![CDATA[乱码]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=753</guid>
		<description><![CDATA[今天在做个小东西，顺便熟悉熟悉phpmaker，结果发现问题了，数据库里面只要是中文的内容 在生成的php来看都是乱码，看了看生成的php，发现压根没声明编码。 搜索mysql_query 在找出的语句上面... ]]></description>
			<content:encoded><![CDATA[<p>今天在做个小东西，顺便熟悉熟悉phpmaker，结果发现问题了，数据库里面只要是中文的内容 在生成的php来看都是乱码，看了看生成的php，发现压根没声明编码。<br />
搜索mysql_query  在找出的语句上面一行加上mysql_query(&#8220;set names gbk&#8221;);搞定。<br />
想不通这软件都做这么强大了，竟然连数据库编码都没考虑</p>
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		</item>
		<item>
		<title>ESX 3升级到ESX 4中的一些小技巧</title>
		<link>http://226617.cn/archives/655.htm</link>
		<comments>http://226617.cn/archives/655.htm#comments</comments>
		<pubDate>Thu, 03 Sep 2009 07:18:16 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[vmware相关]]></category>
		<category><![CDATA[esx]]></category>
		<category><![CDATA[vmware]]></category>
		<category><![CDATA[vSphere4]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=655</guid>
		<description><![CDATA[1.老的ESX3的虚拟机，可以通过停掉虚拟机，浏览数据存储把整个虚拟机文件夹下载到本地，然后再上传到ESX4的数据存储中，然后进到虚拟机文件夹里面对着.vmx文件右键添加到清单，恢复到ESX 4... ]]></description>
			<content:encoded><![CDATA[<p>1.老的ESX3的虚拟机，可以通过停掉虚拟机，浏览数据存储把整个虚拟机文件夹下载到本地，然后再上传到ESX4的数据存储中，然后进到虚拟机文件夹里面对着.vmx文件右键添加到清单，恢复到ESX 4的虚拟机清单里面。<br />
2.老的ESX3虚拟机可以在ESX4直接运行。<br />
3.ESX3的虚拟机进行升级虚拟硬件的时候需要先把vmware tools升级到最新版。<br />
4.可以在留有快照的情况下升级虚拟机硬件，并且升级后能够通过还原快照回到升级前的状态。<br />
5.需要停掉虚拟机后才会在右键菜单里出现升级虚拟机硬件选项。<br />
6.升级虚拟机硬件将会把原来ESX3的虚拟机版本从4 升级到 7，一旦升级后将无法再ESX3的环境里面使用。<br />
7.vSphere Client直接管理ESX4的时候无法直接进行虚拟机克隆操作，只能手工去浏览数据存储，然后自己建个目录，把别的目录里面的虚拟机文件复制粘贴。（这个功能没有有点不方便）</p>
<p>不断添加中。。。</p>
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		</item>
		<item>
		<title>修改linux系统默认语言为英文</title>
		<link>http://226617.cn/archives/652.htm</link>
		<comments>http://226617.cn/archives/652.htm#comments</comments>
		<pubDate>Tue, 04 Aug 2009 15:09:39 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[linux相关]]></category>
		<category><![CDATA[linux]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=652</guid>
		<description><![CDATA[有些人装linux的时候喜欢选中文，结果装完了ssh进去非得用utf8才能显示正常，而且中文提示都感觉怪怪的，还是英文看的舒服 编辑/etc/sysconfig/i18n 把内容改为 LANG=&#8221;en_US.UTF-8&#8243; SYSFONT=&#8221;... ]]></description>
			<content:encoded><![CDATA[<p>有些人装linux的时候喜欢选中文，结果装完了ssh进去非得用utf8才能显示正常，而且中文提示都感觉怪怪的，还是英文看的舒服<br />
编辑/etc/sysconfig/i18n<br />
把内容改为<br />
LANG=&#8221;en_US.UTF-8&#8243;<br />
SYSFONT=&#8221;latarcyrheb-sun16&#8243;</p>
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		</item>
		<item>
		<title>转战嘀咕</title>
		<link>http://226617.cn/archives/646.htm</link>
		<comments>http://226617.cn/archives/646.htm#comments</comments>
		<pubDate>Mon, 20 Jul 2009 15:55:26 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[只谈心情]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=646</guid>
		<description><![CDATA[目前twitter被墙（虽然我很习惯翻墙），饭否遭谋杀。 所以主用 嘀咕，欢迎大家加我 加入嘀咕并跟随我 嘀咕：sheaven twitter：sheaven79 饭否：Im.龙飞 叽歪：sheaven 做啥：sheaven 没想到这篇博客发了... ]]></description>
			<content:encoded><![CDATA[<p>目前twitter被墙（虽然我很习惯翻墙），饭否遭谋杀。<br />
所以主用 嘀咕，欢迎大家加我 <a href="http://digu.com/jump?aid=reg&#038;mid=sheaven&#038;type=link">加入嘀咕并跟随我</a></p>
<p>嘀咕：sheaven<br />
twitter：sheaven79<br />
饭否：Im.龙飞<br />
叽歪：sheaven<br />
做啥：sheaven</p>
<p>没想到这篇博客发了2天上面的迷博全挂了，这真的不是我干的。<br />
不信我马上用回滔滔，大家看看滔滔会不会挂</p>
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		</item>
		<item>
		<title>用phpcws的请注意更新到1.0.1原来的过期了</title>
		<link>http://226617.cn/archives/639.htm</link>
		<comments>http://226617.cn/archives/639.htm#comments</comments>
		<pubDate>Wed, 08 Jul 2009 14:58:37 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[软件相关]]></category>
		<category><![CDATA[phpcws]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=639</guid>
		<description><![CDATA[犹豫phpcws使用的分词组件是ICTCLAS的共享版，原来的于7.6过期了，所以会造成函数结果输出是空白，只要把phpcws更新下就能恢复正常了... ]]></description>
			<content:encoded><![CDATA[<p>犹豫phpcws使用的分词组件是ICTCLAS的共享版，原来的于7.6过期了，所以会造成函数结果输出是空白，只要把phpcws更新下就能恢复正常了。</p>
]]></content:encoded>
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		<item>
		<title>透明DNS解译设定限制网络访问(Linux+iptables+bind)</title>
		<link>http://226617.cn/archives/636.htm</link>
		<comments>http://226617.cn/archives/636.htm#comments</comments>
		<pubDate>Thu, 02 Jul 2009 15:05:48 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[linux相关]]></category>
		<category><![CDATA[bind]]></category>
		<category><![CDATA[iptables]]></category>
		<category><![CDATA[linux]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=636</guid>
		<description><![CDATA[实现目的 1.linux网关用iptables配置DNS拦截,记录全部机器的DNS请求(什么时候上了什么网站) 2.利用DNS欺骗禁止用户防问部分网站 将需禁止的网站域名指向一个错误的IP地址 方法 1.将所有进入网关的... ]]></description>
			<content:encoded><![CDATA[<p>实现目的<br />
1.linux网关用iptables配置DNS拦截,记录全部机器的DNS请求(什么时候上了什么网站)<br />
2.利用DNS欺骗禁止用户防问部分网站 将需禁止的网站域名指向一个错误的IP地址</p>
<p>方法<br />
1.将所有进入网关的DNS请求，都转向本机的53端口，这样，既使内网PC使了其它的DNS服务器，最终也是由网关解析。<br />
一条iptables的指令即可<br />
iptables -t nat -A PREROUTING -p udp –dport 53 -j REDIRECT –to-port 53</p>
<p>2.DNS设置<br />
bind的设置文件named.conf，设定将请示转发到ISP的DNS，比如说深圳电信的DNS服务器202.96.128.68; 202.96.134.133<br />
设定要禁止用户防问网站test.com<br />
设定查询记录记在/var/named/query.log,查看此记录可以看到用户上了那些网站<br />
记得将目录/var/named的属主改成named chown -R named:named /var/named 否则无法生成/var/named/query.log</p>
<p>[root@gw ~]# cat /etc/named.conf<br />
// Default named.conf generated by install of bind-9.2.4-30.el4</p>
<p>options {<br />
directory “/var/named”;<br />
dump-file “/var/named/data/cache_dump.db”;<br />
statistics-file “/var/named/data/named_stats.txt”;<br />
forwarders { 202.96.128.68; 202.96.134.133; };<br />
};</p>
<p>zone “test.com” IN {<br />
type master;<br />
file “test.com.zone”;<br />
};</p>
<p>logging{<br />
channel query_log {<br />
file “query.log” versions 3 size 20m;<br />
severity info;<br />
print-time yes;<br />
print-category   yes;<br />
};<br />
category queries {<br />
query_log;<br />
};<br />
};</p>
<p>域指定文件将*.test.com指向127.0.0.1<br />
cat /var/named/test.com.zone<br />
$ttl    1D<br />
@               IN SOA  test.com.  root.test.com. (</p>
<p>1053891162<br />
3H<br />
15M<br />
1W<br />
1D )</p>
<p>IN NS          test.com.<br />
IN MX    5    test.com.<br />
www                IN A          127.0.0.1<br />
*                  IN A          127.0.0.1</p>
<p>启动bind<br />
/etc/init.d/named start</p>
<p>执行IP转发<br />
iptables -t nat -A PREROUTING -p udp –dport 53 -j REDIRECT –to-port 53</p>
<p>看看日志如下<br />
[root@gw ~]# !ta<br />
tail -f /var/named/query.log<br />
Jun 08 16:46:18.930 queries: client 192.168.10.193#55856: query: updatem.360safe.com IN A<br />
Jun 08 16:46:19.311 queries: client 192.168.10.182#61239: query: policy.store.qq.com IN A<br />
Jun 08 16:46:20.329 queries: client 192.168.10.182#54165: query: route.store.qq.com IN A<br />
Jun 08 16:46:20.784 queries: client 192.168.10.182#65321: query: xanewp.photo.qq.com IN A<br />
Jun 08 16:46:20.790 queries: client 192.168.10.182#58162: query: app.photo.qq.com IN A<br />
Jun 08 16:46:21.089 queries: client 192.168.10.177#65300: query: www.microsoft.com IN A<br />
Jun 08 16:46:22.939 queries: client 192.168.10.182#64573: query: s21.photo.store.qq.com IN A<br />
Jun 08 16:46:23.182 queries: client 192.168.10.182#52749: query: s17.photo.store.qq.com IN A<br />
Jun 08 16:46:23.266 queries: client 192.168.10.204#51395: query: user.qzone.qq.com IN A<br />
Jun 08 16:46:24.440 queries: client 192.168.10.204#56676: query: pingfore.qq.com IN A<br />
Jun 08 16:46:24.770 queries: client 192.168.10.204#57851: query: users.qzone.qq.com IN A<br />
Jun 08 16:46:24.839 queries: client 192.168.10.204#50360: query: base.qzone.qq.com IN A<br />
Jun 08 16:46:24.843 queries: client 192.168.10.204#61001: query: taotao.qq.com IN A<br />
Jun 08 16:46:24.883 queries: client 192.168.10.204#53403: query: ic.qzone.qq.com IN A<br />
Jun 08 16:46:25.176 queries: client 192.168.10.204#64821: query: qlogo4.store.qq.com IN A<br />
Jun 08 16:46:25.426 queries: client 192.168.10.204#60886: query: g.qzone.qq.com IN A<br />
Jun 08 16:46:26.435 queries: client 192.168.10.204#60875: query: vip.qzone.qq.com IN A<br />
Jun 08 16:46:26.730 queries: client 192.168.10.204#53668: query: cityapi.qzone.qq.com IN A<br />
Jun 08 16:46:27.227 queries: client 192.168.10.204#61486: query: daren4.store.qq.com IN A<br />
Jun 08 16:46:27.235 queries: client 192.168.10.197#55670: query: profile.qshop.qq.com IN A<br />
Jun 08 16:46:27.335 queries: client 192.168.10.204#64822: query: broadcast.qq.com IN A<br />
Jun 08 16:46:27.626 queries: client 192.168.10.202#56066: query: qzone-client.qq.com IN A</p>
<p>在客户端测试结果，我的NB的DNS是设为202.96.128.68<br />
C:\Documents and Settings\li>nslookup www.test.com<br />
*** Can’t find server name for address 202.96.128.68: Non-existent domain<br />
*** Can’t find server name for address 202.96.134.133: Non-existent domain<br />
*** Default servers are not available<br />
Server:  UnKnown<br />
Address:  202.96.128.68</p>
<p>Name:    www.test.net<br />
Address:  127.0.0.1</p>
<p>C:\Documents and Settings\li>nslookup 12134.test.com<br />
*** Can’t find server name for address 202.96.128.68: Non-existent domain<br />
*** Can’t find server name for address 202.96.134.133: Non-existent domain<br />
*** Default servers are not available<br />
Server:  UnKnown<br />
Address:  202.96.128.68</p>
<p>Name:    12134.test.com<br />
Address:  127.0.0.1</p>
<p>原文：http://www.opvps.com/?p=320</p>
]]></content:encoded>
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		</item>
		<item>
		<title>自动升级WordPress插件超时Operation timed out after 30</title>
		<link>http://226617.cn/archives/634.htm</link>
		<comments>http://226617.cn/archives/634.htm#comments</comments>
		<pubDate>Tue, 02 Jun 2009 04:45:46 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[软件相关]]></category>
		<category><![CDATA[wordpress]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=634</guid>
		<description><![CDATA[默认情况下WordPress插件自动升级时候的超时是30秒，但是往往服务器网速的原因30秒没无法下载完成新的插件安装包导致提示超时： 正在从 http://downloads.wordpress.org/plugin/super-switch.1.3.zip 下载更新... ]]></description>
			<content:encoded><![CDATA[<p>默认情况下WordPress插件自动升级时候的超时是30秒，但是往往服务器网速的原因30秒没无法下载完成新的插件安装包导致提示超时：</p>
<p>正在从 http://downloads.wordpress.org/plugin/super-switch.1.3.zip 下载更新</p>
<p>下载失败。: Operation timed out after 30 seconds with 182448 bytes received</p>
<p>插件升级失败</p>
<p>要解决这个问题可以修改 wp-admin/includes/file.php</p>
<p>把$response = wp_remote_get($url, array(’timeout’ => 30));</p>
<p>30改成300 或 600 后再次自动升级成功了</p>
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		</item>
		<item>
		<title>浅谈VI3升级到vSphere4的步骤</title>
		<link>http://226617.cn/archives/624.htm</link>
		<comments>http://226617.cn/archives/624.htm#comments</comments>
		<pubDate>Sat, 30 May 2009 08:31:58 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[vmware相关]]></category>
		<category><![CDATA[VI3]]></category>
		<category><![CDATA[vmware]]></category>
		<category><![CDATA[vSphere4]]></category>
		<category><![CDATA[升级]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=624</guid>
		<description><![CDATA[这篇文章是我学习和整理在用于我们单位VI3系统升级至vSphere4的一份学习总结，和升级指导，所有内容都是基于官网文章的个人理解，并非实际操作步骤，所以这里只作为浅谈，希望能够对我以... ]]></description>
			<content:encoded><![CDATA[<p>这篇文章是我学习和整理在用于我们单位VI3系统升级至vSphere4的一份学习总结，和升级指导，所有内容都是基于官网文章的个人理解，并非实际操作步骤，所以这里只作为浅谈，希望能够对我以及广大VI3用户在升级至vSphere4的时候有所帮助。我在正式升级完成后还会再抽空整理补充一下。</p>
<p>首先明确下这里所指的VI3是VirtualCenter、VMware Infrastructure Client、VMware Update Manager、VMware ESX/ESXi、Virtual Machines等等在内的一个整体平台，当然vSphere4也是和VI3这样所指的一个整体平台。</p>
<p>1.首先我们来把VI3和vSphere4所包含的组件来个新旧名称对比，这里只是简单的列举下升级中所涉及到的组件。<br />
                        VI3 | vSphere4<br />
                     VirtualCenter | vCenter Server<br />
VMware Infrastructure Client | vSphere Client<br />
VMware Update Manager则没有变划但是vSphere4中vSphere Client有一个Host Update Utility的工具可以用来升级esx<br />
而license server在vSphere则被取消了，因为vSphere使用了key的方式替代VI3中的flex license方式。当然如果你需要用vCenter Server和vSphere Client来管理VI3的esx的话你还是需要license server。</p>
<p>2.接下来我们先了解下vCenter Server 4.0的需求。<br />
vCenter Server 4.0的硬件需求：<br />
CPU数量：至少2 CPUs，注意不是双核是2个物理CPU<br />
CPU性能：至少2.0GHz Intel or AMD，如果数据库也在一台机器上的话CPU最好再强劲点。<br />
内存：至少3GB，同样如果数据库也在一台机器上的话我想4GB是最起码的了。<br />
硬盘空间：2GB，同样记得算上数据库的。<br />
网络：至少千兆网络环境是必须的。</p>
<p>vCenter Server 4.0的环境需求：<br />
vCenter Server 4.0需要本机的80,389,443,636,902,903,8080,8433,902(UDP)<br />
先检查检查本机是不是有VirtualCenter之外的其他程序占用这些端口。<br />
确保你的VirtualCenter安装路径里面没有包含 逗号(,) 或者 点(.)<br />
确认Network service用户组对你准备安装vCenter Server 4.0路径的根目录拥有读权限。<br />
确认安装vCenter Server 4.0的系统的计算机名称不超过15个字符。</p>
<p>vCenter Server 4.0的数据库需求：<br />
vCenter Server 4.0的数据库不再支持SQL Server 2000了，所以你必须要先把数据库升级到SQL Server 2005或者2008。<br />
虽然vCenter Server 4.0可以按照在64位系统上，但是请注意必须要使用32位的ODBC驱动来创建DSN</p>
<p>最后我想最起码得备份下VirtualCenter的数据吧。</p>
<p>虽然这些要求一般都很老套，但是往往有时候出现问题就是出在这个上面，所以建议还是对照着看一遍。</p>
<p>3.ESX4的相关需求<br />
ESX4的要求相对来讲就要简单很多了基本在运行的esx3的机器都没什么问题，只是在ESX3升级到ESX4的时候有些需求要注意下<br />
ESX3的本机VMFS卷或者是集群共享的VMFS卷至少有10GB的剩余空间<br />
在HA环境下的ESX3升级到ESX4的时候确保有可用的剩余故障切换容量，不然就只能关VM了。<br />
最后备份下ESX主机上的service console文件，.vmx文件，自定义脚本文件，host configuration和本机的VMFS卷。</p>
<p>4.Virtual Machines的相关需求<br />
虚拟机要求更简单了，在升级VM hardware的时候确保VM没有suspend文件，另外我想VM的硬件里面都有个CDROM的吧，升级VMware Tools需要用到。<br />
最后一步，非常重要，你要清楚的知道一旦对VM进行hardware upgrade就没办法回头了，所以至少在进行upgrade前对VM建一个快照，当然最好是把VM备份一下，不管你用何种方法。</p>
<p>5.升级第一步升级VMware vCenter Server<br />
放入VMware vCenter Server光盘，或者把解压缩VMware vCenter Server安装包，运行autorun.exe在出来的vCenter Server 4.0安装界面上选择vCenter Server开始升级，基本上整个过程和安装并无太大区别，当中会有提示输入key，也可以留空安装完之后在vCenter Server里面输入，在升级数据库的时候注意下。最后安装完成会要求重启，重启后VMware vCenter Server的升级就完成了。<br />
VMware vCenter Server升级完成后我们需要把老的<br />
VMware Converter Enterprise Client 4.0.2<br />
VMware Update Manager Client 1.0u3<br />
在添加删除里面卸载掉，记得按照步骤来哦其它东西不要急的卸载还有用的。</p>
<p>卸载完成后打开原先的VMware Infrastructure Client没错就是老的，输入vc用户和密码后登陆，会弹出一个需求软件安装的对话框 有安装和下载2个选项，这里直接选择安装就行。然后就会自动安装vSphere Client，安装的时候注意勾选安装Install vSphere Host Update Utility 4.0，安装完成后双击桌面VMware vSphere Client，出来登陆框这里可以直接勾选Use windows session credentials这点比以前方便，点登陆后会有个证书警告的对话框这里可以勾选下面安装选项并点忽略。等会就进入了vCenter Server管理界面了。</p>
<p>接下来同样用VMware vCenter Server光盘安装Update Manager、Converter、Guided Consolidation，这里也基本没有什么难度照着安装界面说明来就行。<br />
安装完成后进入vCenter Server在plugins菜单里下载安装vCenter Server的Update Manager、Converter插件。</p>
<p>到这里第一步升级VMware vCenter Server就算完成了。</p>
<p>6.升级第二步升级VMware ESX<br />
ESX的升级有3种方法Update Manager、Host Update Utility或者用光盘安装<br />
Update Manager方式：<br />
进入vCenter Server选择HOME-Hosts and cluster<br />
随便选择一台esx主机在Update Manager选单中选择PATCH方式的Baselines右键选择Detach Baseline把老的更新的基准删除，在选择Detach Baseline会有一个Hosts and cluster选择框，可以全选这样就能一步删除所有的Update Manager中的基准了。<br />
再进入HOME-Update Manager，在上部选择upgrade Baseline，新建一个基准，注意在新建的时候下面确认选择的是host upgrade类型，下一步选择ESX upgrade iso，browse选择下载好的esx4的iso文件，再下一步如果有个证书警告的对话框勾选下面安装选项并点忽略，接下来会有一个上传过程，等待结束后继续下一部选择COS VMDK location 这里如果ESX本地VMDK有10GB剩余空间的话就选第一个，如果本机VMDK空间不足就选择第二项让系统自动选择或者第三项自己制定个共享的VMDK，后面反复下一步知道finish。这样一个host upgrade的Baseline就建好了。<br />
回到HOME-Hosts and cluster选中要升级的esx进入Update Manager选单，attach刚刚建立好的Baseline，添加完成后scan选择upgrades对主机进行一次扫描，扫描完成后会有提示需要upgrade，选择下面的remediate，进入修复界面按照提示下一步当中也会有个COS VMDK location 的选择参照上面的说明选择继续下一步只到完成，这时候就会有修复任务在对esx进行升级了。经过一个漫长的等待期间esx还会进行重启，所有会有断开的警告，这都属正常，到最后升级完成esx就恢复正常状态了，如果有大批量的机器需要升级可以把Baseline附加到整个cluster，这样扫描和修复就是批量化了。</p>
<p>Host Update Utility方式：<br />
可能在某些安装环境下比如服务器有多个ip，修改过端口啊，还有计算机名称和dns name不一样啊都会导致Update Manager出现各种问题（可以搜索下我以前写过的2篇关于Update Manager故障的博文），导致无法正常Update Manager，那么我们就要使用Host Update Utility来进行升级了。<br />
在开始菜单-程序-vmware里选择vSphere Host Update Utility 4.0进入Host Update Utility<br />
Host Update Utility的方式升级相对Update Manager要简单许多，适合esx机器数量较少的环境，在进入Host Update Utility后会有个选择下载patch的对话框，这里选择no，因为我们是upgrade不是打补丁。<br />
首先要在vSphere Server里面把你需要升级的esx进入维护模式并且从cluster里面断开。<br />
如果列表里面没有你的esx可以通过上方的add host添加，选择需要更新的esx主机点击下方的upgrade host进入下一步，选择esx4的iso，继续下一步一直到console os setting 也就是COS 设置，按照前面的规则选择一个合适的VMDK卷下方的disk size选择10GB，总得留点余地。然后一直下一步直到finish，开始升级。升级完成后再在vSphere Server的cluster重新连接升级完成的esx。</p>
<p>至于光盘安装的升级方式这里就不说了，基本和安装也没太多区别，不过也记得先进入维护模式并且从cluster里面断开后在升级。</p>
<p>升级第二步升级VMware ESX到这里就结束了。</p>
<p>7.升级第三步升级VM的VMtools和Virtual Hardware<br />
vCenter Server和esx都升级完了，可能你已经迫不及待的想体验vSphere的新功能了吧，对于新建VM来讲确实你已经可以开始体验了，但是别忘了我们还有一堆老的VM等着升级才能发挥vSphere的功能。<br />
这里在啰嗦一句，别头脑一热把备份VM忘了。</p>
<p>升级VM的VMtools<br />
升级VM的VMtools也是通过Update Manager来进行的，和esx升级不同的是，vSphere Server已经有内建的Baseline了只需要附加到VM就可以具体过程就不多说了参考上面esx upgrade的Update Manager部分，一共要attach2个Baseline，VMware Tools Upgrade to Match Host和VMware Hardware Upgrade to Match Host。然后进行scan和remediate进行升级VMware Tools。</p>
<p>升级Virtual Hardware<br />
升级Virtual Hardware要注意几点，1.必须删除全部快照，2.必须关闭VM，注意是关闭，不是挂起。在关闭VM后VM菜单下面才会出现Upgrade Virtual Hardware，点击后完成更新。这里在提醒下别忘了备份VM，否则后果自负。Virtual Hardware<br />
升级完成后会发现vm概览页面VM version会变成7。</p>
<p>第三步升级VM的VMtools和Virtual Hardware到这就结束了。</p>
<p>8.第四步license<br />
前面说过vSphere的license和VI3有着本质区别，vSphere是以key的方式的。在vSphere Server的HOME-Licensing，这里是整个vSphere Server的license管理中心，可以添加各种license。前面也提到过vSphere Server是兼容VI3的license server的，正常升级的话你应该在这个页面里面看见有license server，可以在administrator菜单里的vSphere Server settings里面修改license server地址，以用于vSphere Server 管理ESX3的主机。<br />
vSphere 的license可以通过HOME-Licensing右上方的 Manage vSphere licenses进行添加并且分配给esx主机和vSphere Server。</p>
<p>第四步license基本就是这样了。</p>
<p>到这里整个升级流程基本上就介绍完了，虽然只是纯理论，但是我已经尽可能的接近实际操作的方式去描述了，下面我会我们的测试系统进行升级，来验证下本文的内容，到时候有问题直接在这里修改了，同时也希望大家发现问题的话帮忙纠正错误。<br />
最后祝大家升级一次成功。 <img src='http://226617.cn/wp-includes/images/smilies/icon_mrgreen.gif' alt=':mrgreen:' class='wp-smiley' />  </p>
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		<item>
		<title>windows下php5无法加载部分扩展dll问题解决</title>
		<link>http://226617.cn/archives/621.htm</link>
		<comments>http://226617.cn/archives/621.htm#comments</comments>
		<pubDate>Tue, 26 May 2009 03:28:20 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[php相关]]></category>
		<category><![CDATA[windows相关]]></category>
		<category><![CDATA[php]]></category>
		<category><![CDATA[环境变量]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=621</guid>
		<description><![CDATA[在windows下开启php的扩展是靠php.ini里面extension部分控制的，但是有部分扩展比如php_curl.dll、php_mcrypt.dll等开启后会在启动的时候提示PHP startup: Unable to load dynamic library的错误，这是因为这部分扩展... ]]></description>
			<content:encoded><![CDATA[<p>在windows下开启php的扩展是靠php.ini里面extension部分控制的，但是有部分扩展比如php_curl.dll、php_mcrypt.dll等开启后会在启动的时候提示PHP startup: Unable to load dynamic library的错误，这是因为这部分扩展还依赖一些dll库才能运行，而这些dll就在php的根目录下，所以按照install.txt文档里面的建议就是把 php所在的目录加到系统环境变量里面。当然加完后记得重启下机器，也可用修改完成后，进入DOS命令提示符，输入：set PATH=C: ，关闭DOS窗口来刷新下系统环境变量。</p>
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		<item>
		<title>Update Manager扫描更新报错vmware.vcIntegrity.MetadataNotFound.fullFormat解决</title>
		<link>http://226617.cn/archives/613.htm</link>
		<comments>http://226617.cn/archives/613.htm#comments</comments>
		<pubDate>Tue, 12 May 2009 15:09:14 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[vmware相关]]></category>
		<category><![CDATA[Update Manager]]></category>
		<category><![CDATA[vmware]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=613</guid>
		<description><![CDATA[这个问题和上次碰到的 patch metadata for xxxx missing 错误其实是一样解决的，上次是用的vc用的8080端口问题报错不太一样。 其实主要就2点 1.esx主机要开放Update Manager相关的防火墙规则，这个可以再... ]]></description>
			<content:encoded><![CDATA[<p>这个问题和上次碰到的 patch metadata for xxxx missing 错误其实是一样解决的，上次是用的vc用的8080端口问题报错不太一样。</p>
<p>其实主要就2点<br />
1.esx主机要开放Update Manager相关的防火墙规则，这个可以再命令行里面添加 也可以在vc里面esx主机的configuration里的security profile里面添加。</p>
<p>2.对于vc服务器有多个ip的情况要修改Update Manager目录下的vci-integrity.xml<br />
找到<br />
&lt;hostconfig&gt;<br />
下面的<br />
&lt;patchdepoturl&gt;&lt;/patchdepoturl&gt;<br />
改为<br />
&lt;patchdepoturl&gt;http://192.168.0.1/vci/hostupdates/hostupdate&lt;/patchdepoturl&gt;<br />
192.168.0.1为esx能访问的到的vc的ip，如果vc端口不是80的话就用192.168.0.1:端口</p>
<p>还有一个地方就是 &lt;vpxdlocation&gt;https://hostname:443/&lt;/vpxdlocation&gt;<br />
这个地方同样要改成esx能访问到的地址而不是默认的hostname，&lt;vpxdlocation&gt;https://192.168.0.1:443/&lt;/vpxdlocation&gt;</p>
<p>这样再定义好Update Manager的基准baselines分配给esx就基本不会有什么问题了。</p>
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		<item>
		<title>给windows 7的启动菜单添加启动项</title>
		<link>http://226617.cn/archives/604.htm</link>
		<comments>http://226617.cn/archives/604.htm#comments</comments>
		<pubDate>Tue, 05 May 2009 13:30:27 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[windows相关]]></category>
		<category><![CDATA[bcdedit]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=604</guid>
		<description><![CDATA[今天在给本本装了个Ubuntu 9.04，grub装在了Ubuntu的分区，本来是想在windows 7的启动菜单里加个启动项直接去加载Ubuntu分区的，结果进了windows 7 傻眼没找到boot.ini，上网查了查汗原来vista开始就用了... ]]></description>
			<content:encoded><![CDATA[<p>今天在给本本装了个Ubuntu 9.04，grub装在了Ubuntu的分区，本来是想在windows 7的启动菜单里加个启动项直接去加载Ubuntu分区的，结果进了windows 7 傻眼没找到boot.ini，上网查了查汗原来vista开始就用了新的启动模块bcd了，于是又翻了些资料，总结下:</p>
<p>启动菜单是可以添加的 但是必须用 bcdedit.exe来操作，运行方法，开始菜单输入cmd 右键以管理员身份运行。</p>
<p>然后就能输入bcdedit 来查看目前的bcd信息，如果出错，基本是没有以管理员身份运行cmd。</p>
<p>bcdedit /export &#8220;d:\bcd\bcd backup&#8221;</p>
<p>操作前先备份下bcd</p>
<p>添加一个启动菜单的命令是：</p>
<p>bcdedit /create /d &#8220;Ubuntu 9.04&#8243; /application bootsector</p>
<p>正确的话会返回一句类似 “The entry {848f522b-3090-11de-8858-8443ad028695}  was successfully created.”</p>
<p>bcdedit /set {848f522b-3090-11de-8858-8443ad028695} device partition=\Device\HarddiskVolume4</p>
<p>我的Ubuntu是装在第四个分区的所以这里设置的是\Device\HarddiskVolume4，根据实际情况修改</p>
<p>bcdedit /displayorder {848f522b-3090-11de-8858-8443ad028695} /addlast</p>
<p>把刚设置好的启动项加入启动菜单，放在最后。</p>
<p>这里只是演示下如何加菜单，如果要启动Ubuntu的话还需要吧bootsector的内容导出来，这就比较麻烦了，这里顺便推荐个工具EasyBCD  可以很方面的直接添加linux到启动菜单，不过要注意的是安装Ubuntu的时候要把grub安装到所在分区而不是硬盘mbr</p>
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		</item>
		<item>
		<title>如何关闭IIS6的HTTPERR日志</title>
		<link>http://226617.cn/archives/596.htm</link>
		<comments>http://226617.cn/archives/596.htm#comments</comments>
		<pubDate>Wed, 29 Apr 2009 03:20:24 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[windows相关]]></category>
		<category><![CDATA[httperr]]></category>
		<category><![CDATA[iis]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=596</guid>
		<description><![CDATA[默认情况下，2003服务器会把所有IIS访问错误的记录写入 C:\WINDOWS\system32\LogFiles\HTTPERR 下的 log 文件中，如果访问量比较大，可能一段时间后日志文件可能会占满C盘空间，导致服务器死机。同时... ]]></description>
			<content:encoded><![CDATA[<p>默认情况下，2003服务器会把所有IIS访问错误的记录写入 C:\WINDOWS\system32\LogFiles\HTTPERR 下的 log 文件中，如果访问量比较大，可能一段时间后日志文件可能会占满C盘空间，导致服务器死机。同时因为要写入所有的IIS访问记录，如果访问量较大会大大增加服务器CPU占用率</p>
<p>关闭HTTPERR的方法</p>
<p>运行里输入 regedit 进入注册表编辑器<br />
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\HTTP\Parameters]</p>
<p>在右边 点鼠标右键 新建dword值 EnableErrorLogging 重新启动服务器就可以了</p>
<p>&#8220;EnableErrorLogging&#8221;=dword:00000000</p>
<p>重起后，2003不再写入HTTPERR日志文件，可以看到服务器CPU占用明显下降！</p>
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		</item>
		<item>
		<title>linux下实现UDP端口映射</title>
		<link>http://226617.cn/archives/594.htm</link>
		<comments>http://226617.cn/archives/594.htm#comments</comments>
		<pubDate>Fri, 24 Apr 2009 03:23:29 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[linux相关]]></category>
		<category><![CDATA[linux]]></category>
		<category><![CDATA[udp]]></category>
		<category><![CDATA[端口映射]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=594</guid>
		<description><![CDATA[一、实际问题snmp监听端口默认为UPD 161，当监控服务器无法直接访问时，就需要用到端口映射来解决！同样问题还有dns服务器的UPD 53端口。 二、使用nc来映射UPD端口假设被监控服务器的IP为192.168... ]]></description>
			<content:encoded><![CDATA[<p><span class="Apple-style-span" style="border-collapse: separate; color: #000000; font-family: Simsun; font-size: 16px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px;"><span class="Apple-style-span" style="color: #4d4b4c; font-family: Arial; font-size: 13px; line-height: 18px;"></p>
<p style="margin: 0px; padding: 0px 0px 10px; list-style-type: none; text-decoration: none;">一、实际问题<br style="margin: 0px; padding: 0px; list-style-type: none; text-decoration: none;" />snmp监听端口默认为UPD 161，当监控服务器无法直接访问时，就需要用到端口映射来解决！<br style="margin: 0px; padding: 0px; list-style-type: none; text-decoration: none;" />同样问题还有dns服务器的UPD 53端口。</p>
<p style="margin: 0px; padding: 0px 0px 10px; list-style-type: none; text-decoration: none;">二、使用nc来映射UPD端口<br style="margin: 0px; padding: 0px; list-style-type: none; text-decoration: none;" />假设被监控服务器的IP为192.168.1.1；用于端口映射的主机为某个公网IP如59.1.1.1；需要映射的端口为UDP 161转发端口设为1161（自定义建议1024以上端口）<br style="margin: 0px; padding: 0px; list-style-type: none; text-decoration: none;" />在端口映射服务器上操作，要安装nc，一般系统都会安装；<br style="margin: 0px; padding: 0px; list-style-type: none; text-decoration: none;" />【注：nc存在安全漏洞，一定要设定防火墙】</p>
<div class="hl-surround" style="border: 1px solid #c3ced9; margin: 0px 0px 5px; padding: 0px; overflow: auto; list-style-type: none; text-decoration: none; background-color: #f9fbfc; width: auto; height: auto; text-align: left; font-family: Verdana,Tahoma,'Courier New',Courier,monospace;">
<div class="hl-main" style="margin: 0px; padding: 6px 24px; list-style-type: none; text-decoration: none; line-height: 23px; background-color: transparent;">首先使用mkfifo建立管道文件<br style="margin: 0px; padding: 0px; list-style-type: none; text-decoration: none;" />#mkfifo /tmp/snmpfifo<br style="margin: 0px; padding: 0px; list-style-type: none; text-decoration: none;" />通过nc建立端口映射 -l为监听模式 -u为UDP -p为本地端口；将内网监控161端口映射到本地的1161端口上；<br style="margin: 0px; padding: 0px; list-style-type: none; text-decoration: none;" />#nc -l -u -p 1161 &lt; /tmp/snmpfifo | nc -u 192.168.1.1 161 &gt; /tmp/snmpfifo<br style="margin: 0px; padding: 0px; list-style-type: none; text-decoration: none;" />查看netstat 1161是否监听<br style="margin: 0px; padding: 0px; list-style-type: none; text-decoration: none;" />#netstat -nlp |grep :1161<br style="margin: 0px; padding: 0px; list-style-type: none; text-decoration: none;" />udp     0      0 0.0.0.0:1161       0.0.0.0:*          31472/nc</div>
</div>
<p style="margin: 0px; padding: 0px 0px 10px; list-style-type: none; text-decoration: none;">在监控服务器上进行测试是否能采集到数据：</p>
<div class="hl-surround" style="border: 1px solid #c3ced9; margin: 0px 0px 5px; padding: 0px; overflow: auto; list-style-type: none; text-decoration: none; background-color: #f9fbfc; width: auto; height: auto; text-align: left; font-family: Verdana,Tahoma,'Courier New',Courier,monospace;">
<div class="hl-main" style="margin: 0px; padding: 6px 24px; list-style-type: none; text-decoration: none; line-height: 23px; background-color: transparent;">#snmpwalk -c public -v2c 59.1.1.1:1161 if<br style="margin: 0px; padding: 0px; list-style-type: none; text-decoration: none;" />IF-MIB::ifIndex.1 = INTEGER: 1<br style="margin: 0px; padding: 0px; list-style-type: none; text-decoration: none;" />IF-MIB::ifIndex.2 = INTEGER: 2<br style="margin: 0px; padding: 0px; list-style-type: none; text-decoration: none;" />IF-MIB::ifIndex.3 = INTEGER: 3<br style="margin: 0px; padding: 0px; list-style-type: none; text-decoration: none;" />IF-MIB::ifIndex.4 = INTEGER: 4<br style="margin: 0px; padding: 0px; list-style-type: none; text-decoration: none;" />IF-MIB::ifDescr.1 = STRING: lo<br style="margin: 0px; padding: 0px; list-style-type: none; text-decoration: none;" />IF-MIB::ifDescr.2 = STRING: eth0<br style="margin: 0px; padding: 0px; list-style-type: none; text-decoration: none;" />&#8230;.</div>
</div>
<p style="margin: 0px; padding: 0px 0px 10px; list-style-type: none; text-decoration: none;">设定成功；这里存在一个问题就是nc监听的端口每次一连接就会挂起，采取一个比较笨的办法就是写个restart.sh脚本放在crontab中每分钟执行一次；<br style="margin: 0px; padding: 0px; list-style-type: none; text-decoration: none;" />产生该问题的主要原因我在下面讲socat的时候会分析的；<br style="margin: 0px; padding: 0px; list-style-type: none; text-decoration: none;" />针对snmp采集这样是没有问题，如果dns服务就不行啦！</p>
<p style="margin: 0px; padding: 0px 0px 10px; list-style-type: none; text-decoration: none;">三、采用nc升级版本的socat来实现UDP端口映射<br style="margin: 0px; padding: 0px; list-style-type: none; text-decoration: none;" />软件包下载地址：http://www.dest-unreach.org/socat/download/<br style="margin: 0px; padding: 0px; list-style-type: none; text-decoration: none;" />安装无非就是configure make make install<br style="margin: 0px; padding: 0px; list-style-type: none; text-decoration: none;" />socat的主要特点就是在两个数据流之间建立通道；且支持众多协议和链接方式：ip, tcp, udp, ipv6, pipe,exec,system,open,proxy,openssl,socket等<br style="margin: 0px; padding: 0px; list-style-type: none; text-decoration: none;" />这里不一一介绍啦！<br style="margin: 0px; padding: 0px; list-style-type: none; text-decoration: none;" />有兴趣可以查看官方文档：http://www.dest-unreach.org/socat/doc/socat.html<br style="margin: 0px; padding: 0px; list-style-type: none; text-decoration: none;" />我们说说如何使用socat建立UPD端口映射</p>
<div class="hl-surround" style="border: 1px solid #c3ced9; margin: 0px 0px 5px; padding: 0px; overflow: auto; list-style-type: none; text-decoration: none; background-color: #f9fbfc; width: auto; height: auto; text-align: left; font-family: Verdana,Tahoma,'Courier New',Courier,monospace;">
<div class="hl-main" style="margin: 0px; padding: 6px 24px; list-style-type: none; text-decoration: none; line-height: 23px; background-color: transparent;">#socat udp4-listen:11161,reuseaddr,fork UDP:[监控服务器IP]:161<br style="margin: 0px; padding: 0px; list-style-type: none; text-decoration: none;" />udp4-listen：在本地建立的是一个udp ipv4协议的监听端口；<br style="margin: 0px; padding: 0px; list-style-type: none; text-decoration: none;" />reuseaddr，绑定本地一个端口；<br style="margin: 0px; padding: 0px; list-style-type: none; text-decoration: none;" />fork，设定多链接模式，即当一个链接被建立后，自动复制一个同样的端口再进行监听；</div>
</div>
<p style="margin: 0px; padding: 0px 0px 10px; list-style-type: none; text-decoration: none;">【注：nc就是因为缺少fork模式，所以每次监听只能处理一次连接】<br style="margin: 0px; padding: 0px; list-style-type: none; text-decoration: none;" />socat是一个强大的软件，希望与有这方面需求的同仁一起学习这个好的工具！<br style="margin: 0px; padding: 0px; list-style-type: none; text-decoration: none;" />ps：无论是nc方式还是socat方式，启动监听模式都是在前端占用一个shell，所以请在后台执行或者使用screen工具等等！</p>
<p style="margin: 0px; padding: 0px 0px 10px; list-style-type: none; text-decoration: none;"><a href="http://www.hiadmin.com/linux%E4%B8%8B%E5%AE%9E%E7%8E%B0udp%E7%AB%AF%E5%8F%A3%E6%98%A0%E5%B0%84/">http://www.hiadmin.com/linux下实现udp端口映射/</a></p>
<p></span></span></p>
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		<item>
		<title>MySQL字符集设定总结</title>
		<link>http://226617.cn/archives/592.htm</link>
		<comments>http://226617.cn/archives/592.htm#comments</comments>
		<pubDate>Fri, 24 Apr 2009 03:18:48 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[mysql相关]]></category>
		<category><![CDATA[mysql]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=592</guid>
		<description><![CDATA[MySQL(4.1以后版本) 服务器中有六个关键位置使用了字符集的概念，他们是：client 、connection、database、results、server 、system。MySQL有两个字符集概念：一个就是字符集本身，一个是字符集校验规则... ]]></description>
			<content:encoded><![CDATA[<p>MySQL(4.1以后版本) 服务器中有六个关键位置使用了字符集的概念，他们是：client 、connection、database、results、server 、system。MySQL有两个字符集概念：一个就是字符集本身，一个是字符集校验规则。字符集影响数据在传输和存储过程中的处理方式，而字符集校验则影响ORDER BY和GROUP BY这些排序方式。<br />
1.和存储有关的<br />
服务器字符集 (@@character_set_server)<br />
库字符集 (@@character_set_database)<br />
表字符集<br />
字段字符集<br />
character_set_server: 服务器安装时指定的默认字符集设定。<br />
character_set_database: 数据库服务器中某个库使用的字符集设定，如果建库时没有指明，将使用服务器安装时指定的字符集设置。<br />
character_system: 数据库系统使用的字符集设定。<br />
在创建一个表的时候，每个字段只要不是binary，都会有一个字符集。如果不指定，那么在SHOW CREATE TABLE的时候，它是不会显示出来的。<br />
建表时候，字段字符集的选取方式如下：<br />
* if 字段指定的字符集<br />
* else if 表指定的字符集<br />
* else if @@character_set_database<br />
* else @@character_set_server (如果没有设定，这个值为latin1)<br />
2.和传输有关的<br />
@@character_set_connection<br />
@@character_set_results<br />
@@character_set_client<br />
character_set_connection: 连接数据库的字符集设置类型，如果php没有指明连接数据库使用的字符集类型就按照服务器端默认的字符设置<br />
character_set_results: 数据库给客户端返回时使用的字符集设定，如果没有指明，使用服务器默认的字符集<br />
character_set_client: 客户端使用的字符集，相当于网页中的字符集设置<br />
3.字符集的校对规则<br />
字符集的校对规则设定分别由上面的character_set_connection, character_set_database, character_set_server决定<br />
collation_connection: 连接字符集的校对规则<br />
collation_database: 默认数据库使用的校对规则。当默认数据库改变时服务器则设置该变量。如果没有默认数据库，变量的值同collation_server<br />
collation_server: 服务器的默认校对规则<br />
以上内容中character_set_client, character_set_connection, character_set_results 受客户端默认字符集影响，其中php编译mysql模块时的默认字符集同样也受到它链接的mysql动态库影响，从而影响到php的character_set_connection, character_set_client设定。当默认字符集不是utf8时，设置my.cnf<br />
[mysqld]<br />
default-character-set=utf8<br />
default-collation=utf8_general_ci<br />
default-character-set只能改变对存储层（server,database,table,column,system）的设定，对于客户端和服务器端的通讯层没有任何影响。<br />
mysql&gt; SHOW VARIABLES LIKE ‘character_set_%’;<br />
+————————–+—————————————————————————+<br />
| Variable_name | Value |<br />
+————————–+—————————————————————————+<br />
| character_set_client | latin1 |<br />
| character_set_connection | latin1 |<br />
| character_set_database | utf8 |<br />
| character_set_filesystem | binary |<br />
| character_set_results | latin1 |<br />
| character_set_server | utf8 |<br />
| character_set_system | utf8<br />
解决字符集通讯设置不匹配的方法：<br />
(修改默认的character_set_client,character_set_connection,character_set_result)<br />
1. 重新编译mysql和php,mysql加入编译参数 –default-character-set=utf8<br />
2. PHP程序在查询数据库之前，执行mysql_query(”set names utf8;”);<br />
3.修改my.cnf，在[mysqld]中加入init-connect=”set names utf8” (对于超级用户连接该选项无效)<br />
4. 启动mysqld 加入参数 –skip-character-set-client-handshake 忽略客户端字符集</p>
<p><a href="http://www.hiadmin.com/mysql%E5%AD%97%E7%AC%A6%E9%9B%86%E8%AE%BE%E5%AE%9A%E6%80%BB%E7%BB%93/">http://www.hiadmin.com/mysql字符集设定总结/</a></p>
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		</item>
		<item>
		<title>linux 和unix下SAR命令的用法</title>
		<link>http://226617.cn/archives/589.htm</link>
		<comments>http://226617.cn/archives/589.htm#comments</comments>
		<pubDate>Wed, 22 Apr 2009 07:52:33 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[linux相关]]></category>
		<category><![CDATA[linux]]></category>
		<category><![CDATA[sar]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=589</guid>
		<description><![CDATA[dmesg可以直接查看cpu的主频，要查看CPU、内存的使用情况可以使用sar！ sar 命令行的常用格式： sar [options] [-A] [-o file] t [n] 在命令行中，n 和t 两个参数组合起来定义采样间隔和次数，t为采样间... ]]></description>
			<content:encoded><![CDATA[<p>dmesg可以直接查看cpu的主频，要查看CPU、内存的使用情况可以使用sar！</p>
<p>sar 命令行的常用格式：<br />
sar [options] [-A] [-o file] t [n]</p>
<p>在命令行中，n 和t  两个参数组合起来定义采样间隔和次数，t为采样间隔，是必须有<br />
的参数，n为采样次数，是可选的，默认值是1，-o file表示将命令结果以二进制格式<br />
存放在文件中，file 在此处不是关键字，是文件名。options 为命令行选项，sar命令<br />
的选项很多，下面只列出常用选项：</p>
<p>-A：所有报告的总和。<br />
-u：CPU利用率<br />
-v：进程、I节点、文件和锁表状态。<br />
-d：硬盘使用报告。<br />
-r：没有使用的内存页面和硬盘块。<br />
-g：串口I/O的情况。<br />
-b：缓冲区使用情况。<br />
-a：文件读写情况。<br />
-c：系统调用情况。<br />
-R：进程的活动情况。<br />
-y：终端设备活动情况。<br />
-w：系统交换活动。</p>
<p>下面将举例说明。</p>
<p>例一：使用命令行 sar -u t n</p>
<p>例如，每60秒采样一次，连续采样5次，观察CPU 的使用情况，并将采样结果以二进制<br />
形式存入当前目录下的文件zhou中，需键入如下命令：</p>
<p># sar -u -o zhou 60 5</p>
<p>屏幕显示：</p>
<p>SCO_SV　　　scosysv　3.2v5.0.5　i80386　　　10/01/2001<br />
14:43:50　　　%usr　　　%sys　　%wio　　　　%idle(-u)<br />
14:44:50　　　0　　　　　1　　　　4　　　　　　94<br />
14:45:50　　　0　　　　　2　　　　4　　　　　　93<br />
14:46:50　　　0　　　　　2　　　　2　　　　　　96<br />
14:47:50　　　0　　　　　2　　　　5　　　　　　93<br />
14:48:50　　　0　　　　　2　　　　2　　　　　　96<br />
Average　　　 0　　　　　2　　　　4　　　　　　94</p>
<p>在显示内容包括：</p>
<p>%usr：CPU处在用户模式下的时间百分比。<br />
%sys：CPU处在系统模式下的时间百分比。<br />
%wio：CPU等待输入输出完成时间的百分比。<br />
%idle：CPU空闲时间百分比。</p>
<p>在所有的显示中，我们应主要注意%wio和%idle，%wio的值过高，表示硬盘存在I/O瓶颈，<br />
%idle值高，表示CPU较空闲，如果%idle值高但系统响应慢时，有可能是CPU等待分配内存，<br />
此时应加大内存容量。%idle值如果持续低于10，那么系统的CPU处理能力相对较低，表<br />
明系统中最需要解决的资源是CPU。</p>
<p>如果要查看二进制文件zhou中的内容，则需键入如下sar命令：</p>
<p># sar -u -f zhou</p>
<p>可见，sar命令即可以实时采样，又可以对以往的采样结果进行查询。</p>
<p>例二：使用命行sar -v t n</p>
<p>例如，每30秒采样一次，连续采样5次，观察核心表的状态，需键入如下命令：</p>
<p># sar -v 30 5</p>
<p>屏幕显示：<br />
SCO_SV scosysv 3.2v5.0.5 i80386 10/01/2001<br />
10:33:23 proc-sz  ov inod-sz ov file-sz ov lock-sz　　 (-v)<br />
10:33:53　305/　321 　0　1337/2764　  0　1561/1706　0　40/　128<br />
10:34:23　308/　321 　0　1340/2764　 0　1587/1706　0　37/　128<br />
10:34:53　305/　321 　0　1332/2764　 0　1565/1706　0　36/　128<br />
10:35:23　308/　321  　0　1338/2764　 0　1592/1706　0　37/　128<br />
10:35:53　308/　321　 0　1335/2764　  0　1591/1706　0　37/　128</p>
<p>显示内容包括：</p>
<p>proc-sz：目前核心中正在使用或分配的进程表的表项数，由核心参数MAX-PROC控制。</p>
<p>inod-sz：目前核心中正在使用或分配的i节点表的表项数，由核心参数<br />
MAX-INODE控制。</p>
<p>file-sz： 目前核心中正在使用或分配的文件表的表项数，由核心参数MAX-FILE控<br />
制。</p>
<p>ov：溢出出现的次数。</p>
<p>Lock-sz：目前核心中正在使用或分配的记录加锁的表项数，由核心参数MAX-FLCKRE<br />
控制。</p>
<p>显示格式为</p>
<p>实际使用表项/可以使用的表项数</p>
<p>显示内容表示，核心使用完全正常，三个表没有出现溢出现象，核心参数不需调整，如<br />
果出现溢出时，要调整相应的核心参数，将对应的表项数加大。</p>
<p>例三：使用命行sar -d t n</p>
<p>例如，每30秒采样一次，连续采样5次，报告设备使用情况，需键入如下命令：</p>
<p>#  sar -d 30 5</p>
<p>屏幕显示：</p>
<p>SCO_SV scosysv 3.2v5.0.5 i80386  10/01/2001<br />
11:06:43 device　%busy　　　avque　　　r+w/s　　blks/s　　avwait avserv (-d)<br />
11:07:13 wd-0　　　1.47　　　2.75　　　4.67　　　14.73　　 5.50 3.14<br />
11:07:43  wd-0　　　0.43　　　18.77　　 3.07　　　8.66　　　25.11 1.41<br />
11:08:13  wd-0　　　0.77　　　2.78　　　2.77　　　7.26　　　4.94 2.77<br />
11:08:43 wd-0　　　1.10　　　11.18　　  4.10　　　11.26　　 27.32 2.68<br />
11:09:13 wd-0　　　1.97　　　21.78　　  5.86　　　34.06　　　69.66 3.35<br />
Average wd-0　　　1.15　　　12.11　　 4.09　　　15.19　　　31.12  2.80</p>
<p>显示内容包括：</p>
<p>device： sar命令正在监视的块设备的名字。<br />
%busy：  设备忙时，传送请求所占时间的百分比。<br />
avque： 队列站满时，未完成请求数量的平均值。<br />
r+w/s：  每秒传送到设备或从设备传出的数据量。<br />
blks/s： 每秒传送的块数，每块512字节。<br />
avwait：  队列占满时传送请求等待队列空闲的平均时间。<br />
avserv： 完成传送请求所需平均时间（毫秒）。</p>
<p>在显示的内容中，wd-0是硬盘的名字，%busy的值比较小，说明用于处理传送请求的有<br />
效时间太少，文件系统效率不高，一般来讲，%busy值高些，avque值低些，文件系统<br />
的效率比较高，如果%busy和avque值相对比较高，说明硬盘传输速度太慢，需调整。</p>
<p>例四：使用命行sar -b t n</p>
<p>例如，每30秒采样一次，连续采样5次，报告缓冲区的使用情况，需键入如下命令：</p>
<p># sar -b 30 5</p>
<p>屏幕显示：</p>
<p>SCO_SV scosysv 3.2v5.0.5 i80386 10/01/2001<br />
14:54:59  bread/s lread/s %rcache bwrit/s lwrit/s %wcache pread/s pwrit/s (-b)<br />
14:55:29　0　　147　　100　 5　　21　　78　　 0　　　0<br />
14:55:59　0　　186　　100　  5　　25　　79　　 0　　　0<br />
14:56:29　4　　232 　　98　 8　　58　　86　　 0　　　0<br />
14:56:59　0　　125　　100　 5　　23　　76　　 0　　　0<br />
14:57:29　0　　 89　　100　  4　　12　　66　　 0　　　0<br />
Average　 1　　156 　　99　 5　　28　　80　　 0　　　0</p>
<p>显示内容包括：</p>
<p>bread/s： 每秒从硬盘读入系统缓冲区buffer的物理块数。<br />
lread/s： 平均每秒从系统buffer读出的逻辑块数。<br />
%rcache： 在buffer cache中进行逻辑读的百分比。<br />
bwrit/s： 平均每秒从系统buffer向磁盘所写的物理块数。<br />
lwrit/s： 平均每秒写到系统buffer逻辑块数。<br />
%wcache： 在buffer cache中进行逻辑读的百分比。<br />
pread/s： 平均每秒请求物理读的次数。<br />
pwrit/s： 平均每秒请求物理写的次数。</p>
<p>在显示的内容中，最重要的是%cache和%wcache两列，它们的值体现着buffer的使用效<br />
率，%rcache的值小于90或者%wcache的值低于65，应适当增加系统buffer的数量，buffer<br />
数量由核心参数NBUF控制，使%rcache达到90左右，%wcache达到80左右。但buffer参数<br />
值的多少影响I/O效率，增加buffer，应在较大内存的情况下，否则系统效率反而得不到<br />
提高。</p>
<p>例五：使用命行sar -g t  n</p>
<p>例如，每30秒采样一次，连续采样5次，报告串口I/O的操作情况，需键入如下命令：</p>
<p># sar -g 30 5</p>
<p>屏幕显示：</p>
<p>SCO_SV scosysv 3.2v5.0.5 i80386　　11/22/2001<br />
17:07:03  　ovsiohw/s　 ovsiodma/s　　ovclist/s (-g)<br />
17:07:33　　　0.00　　　0.00　　　0.00<br />
17:08:03　　　0.00　　　0.00　　　0.00<br />
17:08:33　　　0.00　　　0.00　　　0.00<br />
17:09:03　　　0.00　　　0.00　　　0.00<br />
17:09:33　　　0.00　　　0.00　　　0.00<br />
Average  　　　0.00　　　0.00　　　0.00</p>
<p>显示内容包括：</p>
<p>ovsiohw/s：每秒在串口I/O硬件出现的溢出。</p>
<p>ovsiodma/s：每秒在串口I/O的直接输入输出通道高速缓存出现的溢出。</p>
<p>ovclist/s ：每秒字符队列出现的溢出。</p>
<p>在显示的内容中，每一列的值都是零，表明在采样时间内，系统中没有发生串口I/O溢<br />
出现象。</p>
<p>sar命令的用法很多，有时判断一个问题，需要几个sar命令结合起来使用，比如，怀疑<br />
CPU存在瓶颈，可用sar -u 和sar  -q来看，怀疑I/O存在瓶颈，可用sar -b、sar  -u和sar-d来看。<br />
&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8211;<br />
Sar<br />
-A  所有的报告总和<br />
-a 文件读，写报告<br />
-B 报告附加的buffer cache使用情况<br />
-b buffer cache使用情况<br />
-c  系统调用使用报告<br />
-d 硬盘使用报告<br />
-g 有关串口I/O情况<br />
-h 关于buffer使用统计数字<br />
-m  IPC消息和信号灯活动<br />
-n 命名cache<br />
-p 调页活动<br />
-q 运行队列和交换队列的平均长度<br />
-R 报告进程的活动<br />
-r  没有使用的内存页面和硬盘块<br />
-u CPU利用率<br />
-v 进程，i节点，文件和锁表状态<br />
-w 系统交换活动<br />
-y  TTY设备活动</p>
<p>-a 报告文件读，写报告<br />
&lt;/&gt; sar –a 5 5<br />
SCO_SV scosvr  3.2v5.0.5 PentII(D)ISA 06/07/2002<br />
11:45:40 iget/s namei/s dirbk/s  (-a)<br />
11:45:45 6 2 2<br />
11:45:50 91 20 28<br />
11:45:55 159 20 18<br />
11:46:00  157 21 19<br />
11:46:05 177 30 35<br />
Average 118 18 20</p>
<p>iget/s  每秒由i节点项定位的文件数量<br />
namei/s 每秒文件系统路径查询的数量<br />
dirbk/s  每秒所读目录块的数量</p>
<p>＊这些值越大，表明核心花在存取用户文件上的时间越多，它反映着一些程序和应用文件系统产生的负荷。一般地，如果iget/s与namei/s的比值大于5，并且namei/s的值大于30，则说明文件系统是低效的。这时需要检查文件系统的自由空间，看看是否自由空间过少。</p>
<p>-b  报告缓冲区（buffer cache）的使用情况<br />
&lt;/&gt; sar -b 2 3<br />
SCO_SV scosvr 3.2v5.0.5  PentII(D)ISA 06/07/2002<br />
13:51:28 bread/s lread/s %rcache bwrit/s lwrit/s  %wcache pread/s pwrit/s (-b)<br />
13:51:30 382 1380 72 131 273 52 0 0<br />
13:51:32  378 516 27 6 22 72 0 0<br />
13:51:34 172 323 47 39 57 32 0 0<br />
Average 310 739 58  58 117 50 0 0</p>
<p>bread/s 平均每秒从硬盘（或其它块设备）读入系统buffer的物理块数<br />
lread/s  平均每秒从系统buffer读出的逻辑块数<br />
%rcache 在buffer cache中进行逻辑读的百分比（即100％ &#8211;  bread/lreads）<br />
bwrit/s 平均每秒从系统buffer向磁盘（或其它块设备）所写的物理块数<br />
lwrit/s  平均每秒写到系统buffer的逻辑块数<br />
%wcache 在buffer cache中进行逻辑写的百分比（即100％ &#8211;  bwrit/lwrit）.<br />
pread/sgu 平均每秒请求进行物理读的次数<br />
pwrit/s  平均每秒请求进行物理写的次数</p>
<p>＊所显示的内容反映了目前与系统buffer有关的读，写活。在所报告的数字中，最重要的是%rcache和%wcache（统称为cache命中率）两列，它们具体体现着系统buffer的效率。衡量cache效率的标准是它的命中率值的大小。<br />
＊如果%rcache的值小于90或者%wcache的值低于65，可能就需要增加系统buffer的数量。如果在系统的应用中，系统的I/O活动十分频繁，并且在内存容量配置比较大时，可以增加buffer  cache，使%rcache达到95左右，%wcache达到80左右。<br />
＊系统buffer  cache中，buffer的数量由核心参数NBUF控制。它是一个要调的参数。系统中buffer数量的多少是影响系统I/O效率的瓶颈。要增加系统buffer数量，则要求应该有较大的内存配置。否则一味增加buffer数量，势必减少用户进程在内存中的运行空间，这同样会导致系统效率下降。</p>
<p>-c  报告系统调用使用情况<br />
&lt;/ &gt; sar -c 2 3<br />
SCO_SV scosvr 3.2v5.0.5 PentII(D)ISA  06/07/2002<br />
17:02:42 scall/s sread/s swrit/s fork/s exec/s rchar/s wchar/s  (-c)<br />
17:02:44 2262 169 141 0.00 0.00 131250 22159<br />
17:02:46 1416 61 38 0.00  0.00 437279 6464<br />
17:02:48 1825 43 25 0.00 0.00 109397 42331<br />
Average 1834  91 68 0.00 0.00 225975 23651</p>
<p>scall/s  每秒使用系统调用的总数。一般地，当4~6个用户在系统上工作时，每秒大约30个左右。<br />
sread/s 每秒进行读操作的系统调用数量。<br />
swrit/s  每秒进行写操作的系统调用数量。<br />
fork/s 每秒fork系统调用次数。当4~6个用户在系统上工作时，每秒大约0.5秒左右。<br />
exec/s  每秒exec系统调用次数。<br />
rchar/s 每秒由读操作的系统调用传送的字符（以字节为单位）。<br />
wchar/s  每秒由写操作的系统调用传送的字符（以字节为单位）。<br />
＊如果scall/s持续地大于300，则表明正在系统中运行的可能是效率很低的应用程序。在比较<br />
典型的情况下，进行读操作的系统调用加上进行写操作的系统调用之和，约是scall的一半左右。</p>
<p>-d  报告硬盘使用情况<br />
&lt;/ &gt; sar -d 2 3<br />
SCO_SV scosvr 3.2v5.0.5 PentII(D)ISA  06/07/2002<br />
17:27:49 device %busy avque r+w/s blks/s avwait avserv  (-d)<br />
17:27:51 ida-0 6.93 1.00 13.86 259.41 0.00 5.00<br />
ida-1 0.99 1.00 17.33  290.10 0.00 0.57<br />
17:27:53 ida-0 75.50 1.00 54.00 157.00 0.00 13.98<br />
ida-1  9.50 1.00 12.00 75.00 0.00 7.92<br />
17:27:55 ida-0 7.46 1.00 46.77 213.93 0.00  1.60<br />
ida-1 17.41 1.00 57.71 494.53 0.00 3.02<br />
Average ida-0 29.85 1.00  38.14 210.28 0.00 7.83<br />
ida-1 9.29 1.00 29.02 286.90 0.00  3.20</p>
<p>device 这是sar命令正在监视的块设备的名字。<br />
%busy 设备忙时，运行传送请求所占用的时间。这个值以百分比表示。<br />
avque 在指定的时间周期内，没有完成的请求数量的平均值。仅在队列被占满时取这个值。<br />
r+w/s  每秒传送到设备或者从设备传送出的数据量。<br />
blks/s 每秒传送的块数。每块512个字节。<br />
avwait  传送请求等待队列空闲的平均时间（以毫秒为单位）。仅在队列被占满时取这个值。<br />
avserv  完成传送请求所需平均时间（以毫秒为单位）<br />
＊ida-0和ida-1是硬盘的设备名字。在显示的内容中，如果%busy的值比较小，说明用于处理<br />
传送请求的有效时间太少，文件系统的效率不高。要使文件系统的效率得到优化，应使%busy的数值相对高一些，而avque的值应该低一些。</p>
<p>-g  报告有关串口I/O情况<br />
&lt;/ &gt; sar -g 3 3<br />
SCO_SV scosvr 3.2v5.0.5 PentII(D)ISA  06/13/2002<br />
11:10:09 ovsiohw/s ovsiodma/s ovclist/s (-g)<br />
11:10:12 0.00 0.00  0.00<br />
11:10:15 0.00 0.00 0.00<br />
11:10:18 0.00 0.00 0.00<br />
Average 0.00 0.00  0.00</p>
<p>ovsiohw/s 每秒在串囗I/O硬件出现的溢出。<br />
ovsiodma/s  每秒在串囗I/O的直接输入，输出信道高速缓存出现的溢出。<br />
ovclist/s 每秒字符队列出现的溢出。</p>
<p>-m  报告进程间的通信活动（IPC消息和信号灯活动）情况<br />
&lt;/ &gt; sar -m 4 3<br />
SCO_SV scosvr 3.2v5.0.5  PentII(D)ISA 06/13/2002<br />
13:24:28 msg/s sema/s (-m)<br />
13:24:32 2.24  9.95<br />
13:24:36 2.24 21.70<br />
13:24:40 2.00 36.66<br />
Average 2.16  22.76</p>
<p>msg/s 每秒消息操作的次数（包括发送消息的接收信息）。<br />
sema/s  每秒信号灯操作次数。<br />
＊信号灯和消息作为进程间通信的工具，如果在系统中运行的应用过程中没有使用它们，那么由sar命令报告的msg  和sema的值都将等于0.00。如果使用了这些工具，并且其中或者msg/s大于100，或者sema/s大于100，则表明这样的应用程序效率比较低。原因是在这样的应用程序中，大量的时间花费在进程之间的沟通上，而对保证进程本身有效的运行时间必然产生不良的影响。</p>
<p>-n  报告命名缓冲区活动情况<br />
&lt;/ &gt; sar -n 4 3<br />
SCO_SV scosvr 3.2v5.0.5 PentII(D)ISA  06/13/2002<br />
13:37:31 c_hits cmisses (hit %) (-n)<br />
13:37:35 1246 71  (94%)<br />
13:37:39 1853 81 (95%)<br />
13:37:43 969 56 (94%)<br />
Average 1356 69  (95%)</p>
<p>c_hits cache命中的数量。<br />
cmisses cache未命中的数量。<br />
(hit %)  命中数量/(命中数理+未命中数量)。<br />
＊不难理解，(hit %)值越大越好，如果它低于90％，则应该调整相应的核心参数。</p>
<p>-p  报告分页活动<br />
&lt;/ &gt; sar -p 5 3<br />
SCO_SV scosvr 3.2v5.0.5 PentII(D)ISA  06/13/2002<br />
13:45:26 vflt/s pflt/s pgfil/s rclm/s (-p)<br />
13:45:31 36.25 50.20  0.00 0.00<br />
13:45:36 32.14 58.48 0.00 0.00<br />
13:45:41 79.80 58.40 0.00  0.00<br />
Average 49.37 55.69 0.00 0.00</p>
<p>vflt/s  每秒进行页面故障地址转换的数量（由于有效的页面当前不在内存中）。<br />
pflt/s  每秒来自由于保护错误出现的页面故障数量（由于对页面的非法存，取引起的页面故障）。<br />
pgfil/s  每秒通过”页—入”满足vflt/s的数量。<br />
rclm/s  每秒由系统恢复的有效页面的数量。有效页面被增加到自由页面队列上。<br />
＊如果vflt/s的值高于100，可能预示着对于页面系统来说，应用程序的效率不高，也可能分页参数需要调整，或者内存配置不太合适。</p>
<p>-q  报告进程队列（运行队列和交换队列的平均长度）情况<br />
&lt;/ &gt; sar -q 2 3<br />
SCO_SV scosvr 3.2v5.0.5  PentII(D)ISA 06/13/2002<br />
14:25:50 runq-sz %runocc swpq-sz %swpocc  (-q)<br />
14:25:52 4.0 50<br />
14:25:54 9.0 100<br />
14:25:56 9.0 100<br />
Average 7.3  100</p>
<p>runq-sz 准备运行的进程运行队列。<br />
%runocc 运行队列被占用的时间（百分比）<br />
swpq-sz  要被换出的进程交换队列。<br />
%swpocc  交换队列被占用的时间（百分比）。<br />
＊如果%runocc大于90，并且runq-sz的值大于2，则表明CPU的负载较重。其直接后果，可能使系统的响应速度降低。如果%swpocc大于20，表明交换活动频繁，将严重导致系统效率下降。解决的办法是加大内存或减少缓存区数量，从而减少交换及页—入,页—出活动。</p>
<p>-r  报告内存及交换区使用情况（没有使用的内存页面和硬盘块）<br />
&lt;/&gt; sar -r 2 3<br />
SCO_SV scosvr 3.2v5.0.5  PentII(D)ISA 06/14/2002<br />
10:14:19 freemem freeswp availrmem availsmem  (-r)<br />
10:14:22 279729 6673824 93160 1106876<br />
10:14:24 279663 6673824 93160  1106876<br />
10:14:26 279661 6673824 93160 1106873<br />
Average 279684 6673824 93160  1106875</p>
<p>freemem 用户进程可以使用的内存页面数，4KB为一个页面。<br />
freeswp  用于进程交换可以使用的硬盘盘块，512B为一个盘块。</p>
<p>-u CPU利用率<br />
&lt;/&gt; sar -u 2  3<br />
SCO_SV scosvr 3.2v5.0.5 PentII(D)ISA 06/14/2002<br />
10:27:23 %usr %sys %wio  %idle (-u)<br />
10:27:25 2 3 8 88<br />
10:27:27 3 3 5 89<br />
10:27:29 0 0 0  100<br />
Average 2 2 4 92<br />
.<br />
%usr cpu处在用户模式下时间（百分比）<br />
%sys  cpu处在系统模式下时间（百分比）<br />
%wio cpu等待输入，输出完成（时间百分比）<br />
%idle  cpu空闲时间（百分比）<br />
＊在显示的内容中，%usr和  %sys这两个值一般情况下对系统无特别影响，%wio的值不能太高，如果%wio的值过高，则CPU花在等待输入，输出上的时间太多，这意味着硬盘存在I/O瓶颈。如果%idle的值比较高，但系统响应并不快，那么这有可能是CPU花时间等待分配内存引起的。%idle的值可以较深入帮助人们了解系统的性能，在这种情况上，%idle的值处于40~100之间，一旦它持续低于30，则表明进程竟争的主要资源不是内存而是CPU。<br />
＊在有大量用户运行的系统中，为了减少CPU的压力，应该使用智能多串卡，而不是非智能多串卡。智能多串卡可以承担CPU的某些负担。<br />
＊此外，如果系统中有大型的作业运行，应该把它们合理调度，错开高峰，当系统相对空闲时再运行。</p>
<p>-v  报告系统表的内容（进程，i节点，文件和锁表状态）<br />
&lt;/&gt; sar -v 2 3<br />
SCO_SV scosvr 3.2v5.0.5  PentII(D)ISA 06/14/2002<br />
10:56:46 proc-sz ov inod-sz ov file-sz ov lock-sz  (-v)<br />
10:56:48 449/ 500 0 994/4147 0 1313/2048 0 5/ 128<br />
10:56:50 450/ 500 0  994/4147 0 1314/2048 0 5/ 128<br />
10:56:52 450/ 500 0 994/4147 0 1314/2048 0 5/  128</p>
<p>proc-sz 目前在核心中正在使用或分配的进程表的表项数<br />
inod-sz  目前在核心中正在使用或分配的i节点表的表项数<br />
file-sz 目前在核心中正在使用或分配的文件表的表项数<br />
ov 溢出出现的次数<br />
lock-sz  目前在核心中正在使用或分配的记录加锁的表项数<br />
＊除ov外，均涉及到unix的核心参数，它们分别受核心参数NPROC,NIMODE,NFILE和FLOCKREC的控制。<br />
＊显示格式为：<br />
实际使用表项/整个表可以使用的表项数<br />
比如，proc-sz一列所显示的四个数字中，分母的100是系统中整个进程表的长度（可建立100个表项），分子上的24，26和25分别是采样的那一段时间所使用的进程表项。inod-sz，file-sz和lock-sz三列数字的意义也相同。<br />
三列ov的值分别对应进程表，i节点表和文件表，表明目前这三个表都没有出现溢出现象，当出现溢出时，需要调整相应的核心参数，将对应表加大。</p>
<p>-w  系统交换活动<br />
&lt;/&gt; sar -w 2 3<br />
SCO_SV scosvr 3.2v5.0.5 PentII(D)ISA  06/14/2002<br />
11:22:05 swpin/s bswin/s swpot/s bswots pswch/s (-w)<br />
11:22:07  0.00 0.0 0.00 0.0 330<br />
11:22:09 0.00 0.0 0.00 0.0 892<br />
11:22:11 0.00 0.0  0.00 0.0 1053<br />
Average 0.00 0.0 0.00 0.0 757</p>
<p>swpin/s  每秒从硬盘交换区传送进入内存的次数。<br />
bswin/s 每秒为换入而传送的块数。<br />
swpot/s  每秒从内存传送到硬盘交换区的次数。<br />
bswots 每秒为换出而传送的块数。<br />
pswch/s  每秒进程交换的数量。<br />
＊swpin/s，bswin/s，swpot/s和bswots描述的是与硬盘交换区相关的交换活动。交换关系到系统的效率。交换区在硬盘上对硬盘的读，写操作比内存读，写慢得多，因此，为了提高系统效率就应该设法减少交换。通常的作法就是加大内存，使交换区中进行的交换活动为零，或接近为零。如果swpot/s的值大于1，预示可能需要增加内存或减少缓冲区（减少缓冲区能够释放一部分自由内存空间）。</p>
<p>-y  报告终端的I/O活动（TTY设备活动）情况<br />
&lt;/&gt; sar -y 2 3<br />
SCO_SV scosvr 3.2v5.0.5  PentII(D)ISA 06/14/2002<br />
11:38:03 rawch/s canch/s outch/s rcvin/s xmtin/s  mdmin/s (-y)<br />
11:38:05 5 0 951 0 1 0<br />
11:38:07 10 0 996 0 0 0<br />
11:38:09 4  0 2264 0 0 0<br />
Average 6 0 1404 0 1 0</p>
<p>rawch/s 每秒输入的字符数（原始队列）<br />
canch/s  每秒由正则队列（canonical  queue）处理的输入字符数。进行正则处理过程中，可以识别出一些有特殊意义的字符。比如，&lt;Del&gt;(中断字符)，&lt;ctrl&gt;(退出符)，&lt;Bksp&gt;(退格键)等。因此，canch/s中的计数不包括这些有特殊意义的字符。<br />
outch/s  每秒输出的字符数。<br />
rcvin/s 每秒接收的硬件中断次数。<br />
xmtin/s 每秒发出的硬件中断次数。<br />
mdmin/s  每秒modem中断次数。<br />
＊应该特别说明，sar命令可以对任意终端活动进行统计，所谓任意终端，是指任意tty设备。它们可以是串行终端，主控台，伪终端等等。<br />
＊在这几个量中，modem中断次数mdmin/s应该接近0。其它没有特殊要求，但如果每发送一个字符，中断的数量就动态地增加，这表明终端线出了差错，可能是接触不好。</p>
<p><span style="font-size: x-small;">这个包在各大发行版中都有，如果您试一下有sar这个命令就证明已经有了。如果没有的，可以下载安装上就OK了</span></p>
<p>一、简要介绍：</p>
<p>sysstat这个工具，可以说是linux  &amp;Unix  以及Freebsd最常用的工具。它的主要用途就是观察服务负载，比如CPU和内存的占用率、网络的使用率以及磁盘写入和读取速度等。</p>
<p>sar<br />
iostat<br />
sa1<br />
sa2<br />
sadf<br />
mpstat<br />
sadc<br />
sysstat</p>
<p>这几个命令中，有的是服务，有的是查看结果的命令。也有的是即时服务器CPU，内存以及网络的使用率,比如先要打开sa1  sa2或者sysstat 才能使用sar sadf sadc, 还要即时服务器的CPU，内存，网络使用率的命令，比如：mpstat  iostat<br />
二、安装：</p>
<p>首先您到 [url]http://perso.wanadoo.fr/sebastien.godard/[/url]  下载最新的版本，最好是源码包，比如我下载的是sysstat-5.1.1.tar.gz</p>
<p>安装方法比较简单：</p>
<p>1.解包：</p>
<p>#tar  zxvf sysstat-5.1.1.tar.gz</p>
<p>2.安装：</p>
<p>#cd sysstat-5.1.1<br />
#make config  这步可以省略，因为我在安装的过程 中，发现在有些发行版中出错，如果不用这个命令，可以直接安装到其默认的/usr/local/lib目录中<br />
make  config这个命令就是用来配置sysstat安装的，比如安装路径，log存放等，如下：</p>
<p>代码:<br />
Installation  directory: [/usr/local]<br />
sadc directory: [/usr/local/lib/sa]<br />
System  activity directory: [/var/log/sa]<br />
Clean system activity directory?  [n]<br />
Enable National Language Support (NLS)? [y]<br />
Linux SMP race in serial  driver workaround? [n]<br />
sa2 uses daily data file of previous day?  [n]<br />
Number of daily data files to keep: [7]<br />
Group for manual pages:  [man]<br />
Set crontab to start sar automatically? [n]</p>
<p>#make  注：这步是必须的，如果您不用第一步，这步也是必要的。</p>
<p>#make  install</p>
<p>这样就安装好了。</p>
<p>三、使用：</p>
<p>对于这个工具，如何使用呢？？如果您想看即时  服务器的CPU，内存，网络使用率的命令，比如：mpstat iostat  ，您可以简单的用下面的命令，如果更复杂一点，您可以用man来查看所有命令的用法。</p>
<p>比如：<br />
[beinan@S11 beinan]$  iostat<br />
Linux 2.4.22-2f (S11) 2004年10月30日</p>
<p>avg-cpu: %user %nice %system  %iowait %idle<br />
8.64 0.00 0.95 0.00 90.41<br />
Device: tps Blk_read/s Blk_wrtn/s  Blk_read Blk_wrtn<br />
dev3-0 2.97 55.28 38.84 213314 149856</p>
<p>[beinan@S11  beinan]$ mpstat<br />
Linux 2.4.22-2f (S11) 2004年10月30日</p>
<p>03时13分56秒 CPU %user  %nice %sys %iowait %irq %soft %idle intr/s<br />
03时13分56秒 all 8.56 0.00 0.94 0.00  0.00 0.00 90.50 84.32</p>
<p>比如观察磁盘的读写速度：</p>
<p>[beinan@S11 beinan]$ iostat  -p<br />
Linux 2.4.22-2f (S11) 2004年10月30日</p>
<p>avg-cpu: %user %nice %system  %iowait %idle<br />
33.54 0.00 4.95 0.86 60.65</p>
<p>Device: tps Blk_read/s  Blk_wrtn/s Blk_read Blk_wrtn<br />
hda 26.26 186.57 481.17 16117015  41564960<br />
hda1 3.29 1.33 26.01 115138 2246456<br />
hda2 19.86 26.49 149.65  2288449 12927104<br />
hda3 40.16 158.57 305.51 13697580 26391400<br />
hda5 0.00 0.00  0.00 8 0</p>
<p>如果是想让服务器自动运行，并且想每个小时都有一个数据反馈，我们可以用cron 来让执行sa1  sa2，这样就有一份日志文件存在/var/log/sa/目录中。我们到时运行sar就能知道所有过去时间每个小时运行情况：</p>
<p>可以写一个命令到一个文件中。。。把这个文件设置为755的执行权限，放在/etc/cron.hourly目录中。</p>
<p>[root@S11  root]# cd /etc/cron.hourly/ 进入目录<br />
[root@S11 cron.hourly]# touch sa1ho  创建文件，这个文件名可以自己来命名<br />
[root@S11 cron.hourly]# chmod 755  sa1ho<br />
然后在这个文件中写入下面的一行</p>
<p>/usr/local/lib/sa/sa1&amp;</p>
<p>这样每一个小时，就有日志文件写入/var/log/sa/目录中了，当然还有一个/usr/local/lib/sa/sa2的命令，也可以写一个文件到  在/etc/cron.weekly/目录中，sa2是做什么用的呢？自己先看看帮助文件，当然也可以写入/etc/cron.hourly/  ，这样就每小时一次。</p>
]]></content:encoded>
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		<title>MySQL 中 Join 的基本实现原理</title>
		<link>http://226617.cn/archives/587.htm</link>
		<comments>http://226617.cn/archives/587.htm#comments</comments>
		<pubDate>Wed, 22 Apr 2009 07:41:11 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[mysql相关]]></category>
		<category><![CDATA[join]]></category>
		<category><![CDATA[mysql]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=587</guid>
		<description><![CDATA[在 MySQL 中，只有一种 Join 算法，就是大名鼎鼎的 Nested Loop Join，他没有其他很多数据库所提供的 Hash Join，也没有 Sort Merge Join。顾名思义，Nested Loop Join 实际上就是通过驱动表的结果集作为循环... ]]></description>
			<content:encoded><![CDATA[<p><span class="Apple-style-span" style="border-collapse: separate; color: #111111; font-family: Tahoma; font-size: 14px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px;"><span class="Apple-style-span" style="line-height: 23px;"></p>
<p style="border-width: 0px; margin: 0px 0px 10px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #111111; line-height: 1.7;">在 MySQL 中，只有一种 Join 算法，就是大名鼎鼎的 Nested Loop Join，他没有其他很多数据库所提供的 Hash Join，也没有 Sort Merge Join。顾名思义，Nested Loop Join 实际上就是通过驱动表的结果集作为循环基础数据，然后一条一条的通过该结果集中的数据作为过滤条件到下一个表中查询数据，然后合并结果。如果还有第三个参与 Join，则再通过前两个表的 Join 结果集作为循环基础数据，再一次通过循环查询条件到第三个表中查询数据，如此往复。</p>
<p style="border-width: 0px; margin: 0px 0px 10px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #111111; line-height: 1.7;">还是通过示例和图解来说明吧，后面将通过我个人数据库测试环境中的一个 example（自行设计，非MySQL 自己提供） 数据库中的三个表的 Join 查询来进行示例。</p>
<p style="border-width: 0px; margin: 0px 0px 10px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #111111; line-height: 1.7;">注意：由于这里有些内容需要在MySQL 5.1.18之后的版本中才会体现出来，所以本测试的MySQL 版本为5.1.26</p>
<p style="border-width: 0px; margin: 0px 0px 10px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #111111; line-height: 1.7;">表结构：</p>
<div class="hl-surround" style="border: 1px solid #c3ced9; margin: 0px 0px 5px; padding: 0px; overflow: auto; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Fixedsys,'BitStream Vera Sans Mono','Courier New',Courier,monospace; color: #111111; background-color: #f9fbfc; width: auto; height: auto; text-align: left;">
<div class="hl-main" style="border-width: 0px; margin: 0px; padding: 6px 24px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #111111; line-height: 25px; background-color: transparent;"><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">sky</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">@</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">localhost</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span>:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">example</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">11</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">09</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">32</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">&gt;<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">show</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">create</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">table</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">user_groupG</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
***************************<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">1.</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">row</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span>***************************<br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">Table</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">user_group</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">Create</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">Table</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">CREATE</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">TABLE</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">user_group</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: olive;">(</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">user_id</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">int</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: olive;">(</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">11</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: olive;">)</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">NOT</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">NULL</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">,<br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">group_id</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">int</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: olive;">(</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">11</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: olive;">)</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">NOT</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">NULL</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">,<br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">user_type</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">int</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: olive;">(</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">11</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: olive;">)</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">NOT</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">NULL</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">,<br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">gmt_create</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">datetime</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">NOT</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">NULL</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">,<br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">gmt_modified</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">datetime</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">NOT</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">NULL</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">,<br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">status</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">varchar</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: olive;">(</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">16</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: olive;">)</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">NOT</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">NULL</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">,<br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">KEY</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">idx_user_group_uid</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: olive;">(</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">user_id</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: olive;">)</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: olive;">)</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">ENGINE</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">=</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">MyISAM</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">DEFAULT</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">CHARSET</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">=</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">utf8</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">1</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">row</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">in</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">set</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: olive;">(</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">0.00</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">sec</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: olive;">)</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"></p>
<p></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">sky</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">@</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">localhost</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span>:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">example</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">11</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">10</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">32</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">&gt;<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">show</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">create</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">table</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">group_messageG</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
***************************<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">1.</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">row</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span>***************************<br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">Table</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">group_message</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">Create</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">Table</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">CREATE</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">TABLE</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">group_message</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: olive;">(</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">id</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">int</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: olive;">(</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">11</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: olive;">)</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">NOT</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">NULL</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">AUTO_INCREMENT</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">,<br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">gmt_create</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">datetime</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">NOT</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">NULL</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">,<br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">gmt_modified</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">datetime</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">NOT</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">NULL</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">,<br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">group_id</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">int</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: olive;">(</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">11</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: olive;">)</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">NOT</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">NULL</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">,<br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">user_id</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">int</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: olive;">(</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">11</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: olive;">)</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">NOT</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">NULL</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">,<br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">author</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">varchar</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: olive;">(</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">32</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: olive;">)</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">NOT</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">NULL</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">,<br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">subject</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">varchar</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: olive;">(</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">128</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: olive;">)</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">NOT</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">NULL</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">,<br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">PRIMARY</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">KEY</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: olive;">(</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">id</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: olive;">)</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">,<br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">KEY</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">idx_group_message_author_subject</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: olive;">(</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">author</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">,</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">subject</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: olive;">(</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">16</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: olive;">))</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">,<br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">KEY</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">idx_group_message_author</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: olive;">(</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">author</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: olive;">)</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">,<br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">KEY</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">idx_group_message_gid_uid</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: olive;">(</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">group_id</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">,</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">user_id</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: olive;">)</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: olive;">)</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">ENGINE</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">=</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">MyISAM</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">AUTO_INCREMENT</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">=</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">97</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">DEFAULT</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">CHARSET</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">=</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">utf8</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">1</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">row</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">in</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">set</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: olive;">(</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">0.00</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">sec</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: olive;">)</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"></p>
<p></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">sky</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">@</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">localhost</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span>:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">example</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">11</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">10</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">43</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">&gt;<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">show</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">create</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">table</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">group_message_contentG</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
***************************<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">1.</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">row</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span>***************************<br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">Table</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">group_message_content</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">Create</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">Table</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">CREATE</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">TABLE</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">group_message_content</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: olive;">(</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">group_msg_id</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">int</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: olive;">(</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">11</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: olive;">)</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">NOT</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">NULL</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">,<br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">content</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">text</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">NOT</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">NULL</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">,<br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">KEY</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">group_message_content_msg_id</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: olive;">(</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">group_msg_id</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: olive;">)</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: olive;">)</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">ENGINE</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">=</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">MyISAM</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">DEFAULT</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">CHARSET</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">=</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">utf8</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">1</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">row</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">in</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">set</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: olive;">(</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">0.00</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">sec</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: olive;">)</span></div>
</div>
<p style="border-width: 0px; margin: 0px 0px 10px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #111111; line-height: 1.7;">使用Query如下：</p>
<div class="hl-surround" style="border: 1px solid #c3ced9; margin: 0px 0px 5px; padding: 0px; overflow: auto; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Fixedsys,'BitStream Vera Sans Mono','Courier New',Courier,monospace; color: #111111; background-color: #f9fbfc; width: auto; height: auto; text-align: left;">
<div class="hl-main" style="border-width: 0px; margin: 0px; padding: 6px 24px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #111111; line-height: 25px; background-color: transparent;"><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">select</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">m</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">.</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">subject</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">msg_subject</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">,<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">c</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">.</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">content</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">msg_content</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">from</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">user_group</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">g</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">,</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">group_message</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">m</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">,</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">group_message_content</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">c</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">where</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">g</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">.</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">user_id</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span>=<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">1</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">and</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">m</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">.</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">group_id</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span>=<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">g</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">.</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">group_id</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">and</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">c</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">.</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">group_msg_id</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span>=<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">m</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">.</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">id</span></div>
</div>
<p style="border-width: 0px; margin: 0px 0px 10px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #111111; line-height: 1.7;">看看我们的 Query 的执行计划：</p>
<div class="hl-surround" style="border: 1px solid #c3ced9; margin: 0px 0px 5px; padding: 0px; overflow: auto; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Fixedsys,'BitStream Vera Sans Mono','Courier New',Courier,monospace; color: #111111; background-color: #f9fbfc; width: auto; height: auto; text-align: left;">
<div class="hl-main" style="border-width: 0px; margin: 0px; padding: 6px 24px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #111111; line-height: 25px; background-color: transparent;"><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">sky</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">@</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">localhost</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span>:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">example</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">11</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">17</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">04</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">&gt;<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">explain</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">select</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">m</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">.</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">subject</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">msg_subject</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">,<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">c</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">.</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">content</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">msg_content</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
-&gt;<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">from</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">user_group</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">g</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">,</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">group_message</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">m</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">,</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">group_message_content</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">c</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
-&gt;<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">where</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">g</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">.</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">user_id</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span>=<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">1</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
-&gt;<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">and</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">m</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">.</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">group_id</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span>=<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">g</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">.</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">group_id</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
-&gt;<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">and</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">c</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">.</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">group_msg_id</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span>=<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">m</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">.</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">idG</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
***************************<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">1.</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">row</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span>***************************<br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">id</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">1</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">select_type</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">SIMPLE</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">table</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">g</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">type</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">ref</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">possible_keys</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">user_group_gid_ind</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">,</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">user_group_uid_ind</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">,</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">user_group_gid_uid_ind</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">key</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">user_group_uid_ind</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">key_len</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">4</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">ref</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">const</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">rows</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">2</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">Extra</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<br />
***************************<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">2.</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">row</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span>***************************<br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">id</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">1</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">select_type</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">SIMPLE</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">table</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">m</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">type</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">ref</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">possible_keys</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">PRIMARY</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">,</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">idx_group_message_gid_uid</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">key</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">idx_group_message_gid_uid</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">key_len</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">4</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">ref</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">example</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">.</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">g</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">.</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">group_id</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">rows</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">3</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">Extra</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<br />
***************************<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">3.</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">row</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span>***************************<br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">id</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">1</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">select_type</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">SIMPLE</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">table</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">c</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">type</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">ref</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">possible_keys</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">idx_group_message_content_msg_id</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">key</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">idx_group_message_content_msg_id</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">key_len</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">4</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">ref</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">example</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">.</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">m</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">.</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">id</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">rows</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">2</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">Extra</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:</span></div>
</div>
<p style="border-width: 0px; margin: 0px 0px 10px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #111111; line-height: 1.7;">我们可以看出，MySQL Query Optimizer 选择了 user_group 作为驱动表，首先利用我们传入的条件 user_id 通过 该表上面的索引 user_group_uid_ind 来进行 const 条件的索引 ref 查找，然后以 user_group 表中过滤出来的结果集的 group_id 字段作为查询条件，对 group_message 循环查询，然后再通过 user_group 和 group_message 两个表的结果集中的  group_message 的 id 作为条件 与 group_message_content 的 group_msg_id 比较进行循环查询，才得到最终的结果。没啥特别的，后一个引用前一个的结果集作为条件，实现过程可以通过下图表示：</p>
<p style="border-width: 0px; margin: 0px 0px 10px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #111111; line-height: 1.7;"><img class="aligncenter size-full wp-image-372" style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #111111;" title="nested_join_no_buffer" src="http://www.jianzhaoyang.com/wp-content/uploads/2008/12/nested_join_no_buffer.jpg" alt="" width="500" height="350" /></p>
<p style="border-width: 0px; margin: 0px 0px 10px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #111111; line-height: 1.7;">下面的我们调整一下 group_message_content 去掉上面的 idx_group_message_content_msg_id 这个索引，然后再看看会是什么效果：</p>
<div class="hl-surround" style="border: 1px solid #c3ced9; margin: 0px 0px 5px; padding: 0px; overflow: auto; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Fixedsys,'BitStream Vera Sans Mono','Courier New',Courier,monospace; color: #111111; background-color: #f9fbfc; width: auto; height: auto; text-align: left;">
<div class="hl-main" style="border-width: 0px; margin: 0px; padding: 6px 24px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #111111; line-height: 25px; background-color: transparent;"><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">sky</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">@</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">localhost</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span>:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">example</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">11</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">25</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">36</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">&gt;<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">drop</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">index</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">idx_group_message_content_msg_id</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">on</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">group_message_content</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">;<br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">Query</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">OK</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">,<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">96</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">rows</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">affected</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: olive;">(</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">0.11</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">sec</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: olive;">)</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"></p>
<p></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">sky</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">@</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">localhost</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span>:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">example</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">10</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">21</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">06</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">&gt;<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">explain</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
-&gt;<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">select</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">m</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">.</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">subject</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">msg_subject</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">,<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">c</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">.</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">content</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">msg_content</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
-&gt;<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">from</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">user_group</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">g</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">,</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">group_message</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">m</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">,</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">group_message_content</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">c</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
-&gt;<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">where</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">g</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">.</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">user_id</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span>=<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">1</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
-&gt;<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">and</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">m</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">.</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">group_id</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span>=<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">g</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">.</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">group_id</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
-&gt;<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">and</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">c</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">.</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">group_msg_id</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span>=<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">m</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">.</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">idG</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
***************************<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">1.</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">row</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span>***************************<br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">id</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">1</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">select_type</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">SIMPLE</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">table</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">g</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">type</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">ref</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">possible_keys</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">idx_user_group_uid</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">key</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">idx_user_group_uid</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">key_len</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">4</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">ref</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">const</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">rows</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">2</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">Extra</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<br />
***************************<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">2.</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">row</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span>***************************<br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">id</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">1</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">select_type</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">SIMPLE</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">table</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">m</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">type</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">ref</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">possible_keys</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">PRIMARY</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">,</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">idx_group_message_gid_uid</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">key</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">idx_group_message_gid_uid</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">key_len</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">4</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">ref</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">example</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">.</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">g</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">.</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">group_id</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">rows</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">3</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">Extra</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<br />
***************************<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">3.</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">row</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span>***************************<br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">id</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">1</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">select_type</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">SIMPLE</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">table</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">c</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">type</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">ALL</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">possible_keys</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">NULL</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">key</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">NULL</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">key_len</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">NULL</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">ref</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">NULL</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">rows</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">96</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">Extra</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">Using</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">where</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">;<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">Using</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">join</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">buffer</span></div>
</div>
<p style="border-width: 0px; margin: 0px 0px 10px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #111111; line-height: 1.7;">我们看到不仅仅 group_message_content 表的访问从 ref 变成了 ALL，此外，在最后一行的 Extra信息从没有任何内容变成为  Using where; Using join buffer，也就是说，对于从 ref 变成 ALL 很容易理解，没有可以使用的索引的索引了嘛，当然得进行全表扫描了，Using where 也是因为变成全表扫描之后，我们需要取得的 content 字段只能通过对表中的数据进行 where 过滤才能取得，但是后面出现的 Using join buffer 是一个啥呢？</p>
<p style="border-width: 0px; margin: 0px 0px 10px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #111111; line-height: 1.7;">我们知道，MySQL 中有一个供我们设置的参数 join_buffer_size ，这里实际上就是使用到了通过该参数所设置的 Buffer 区域。那为啥之前的执行计划中没有用到呢？</p>
<p style="border-width: 0px; margin: 0px 0px 10px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #111111; line-height: 1.7;">实际上，Join Buffer 只有当我们的 Join 类型为 ALL（如示例中），index，rang 或者是 index_merge 的时候 才能够使用，所以，在我们去掉 group_message_content 表的 group_msg_id 字段的索引之前，由于 Join 是 ref 类型的，所以我们的执行计划中并没有看到有使用 Join Buffer。</p>
<p style="border-width: 0px; margin: 0px 0px 10px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #111111; line-height: 1.7;">当我们使用了 Join Buffer 之后，我们可以通过下面的这张图片来表示 Join 完成过程：<br />
<img class="aligncenter size-full wp-image-564" style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #111111;" title="nested_join_with_buffer" src="http://www.jianzhaoyang.com/wp-content/uploads/2008/12/nested_join_with_buffer_jianzhaoyangcom.png" alt="nested_join_with_buffer" width="500" height="350" />
</p>
<p style="border-width: 0px; margin: 0px 0px 10px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #111111; line-height: 1.7;"><span class="Apple-style-span" style="border-collapse: separate; color: #111111; font-family: Tahoma; font-size: 14px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px;"><span class="Apple-style-span" style="color: #939393;">作者：<a style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #939393; text-decoration: none;" href="http://www.jianzhaoyang.com/">Sky.Jian</a></span></span></p>
<p style="border-width: 0px; margin: 0px 0px 10px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #111111; line-height: 1.7;"><span class="Apple-style-span" style="border-collapse: separate; color: #111111; font-family: Tahoma; font-size: 14px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px;"><span class="Apple-style-span" style="color: #939393;">链接：<a style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #939393; text-decoration: none;" href="http://www.jianzhaoyang.com/database/mysql_join_buffer_nested_loop_implement">http://www.jianzhaoyang.com/database/mysql_join_buffer_nested_loop_implement</a></span></span></p>
<p style="border-width: 0px; margin: 0px 0px 10px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #111111; line-height: 1.7;">
<p></span></span></p>
]]></content:encoded>
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		<item>
		<title>MySQL ORDER BY 的实现分析</title>
		<link>http://226617.cn/archives/585.htm</link>
		<comments>http://226617.cn/archives/585.htm#comments</comments>
		<pubDate>Wed, 22 Apr 2009 07:39:17 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[mysql相关]]></category>
		<category><![CDATA[mysql]]></category>
		<category><![CDATA[order by]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=585</guid>
		<description><![CDATA[总的来说，在 MySQL 中的ORDER BY有两种排序实现方式，一种是利用有序索引获取有序数据，另一种则是通过相应的排序算法，将取得的数据在内存中进行排序。 下面将通过实例分析两种排序实现... ]]></description>
			<content:encoded><![CDATA[<p><span class="Apple-style-span" style="border-collapse: separate; color: #111111; font-family: Tahoma; font-size: 14px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px;"><span class="Apple-style-span" style="line-height: 23px;"></p>
<p style="border-width: 0px; margin: 0px 0px 10px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #111111; line-height: 1.7;">总的来说，在 MySQL 中的ORDER BY有两种排序实现方式，一种是利用有序索引获取有序数据，另一种则是通过相应的排序算法，将取得的数据在内存中进行排序。</p>
<p style="border-width: 0px; margin: 0px 0px 10px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #111111; line-height: 1.7;">下面将通过实例分析两种排序实现方式及实现图解：<br />
假设有 Table A 和 B 两个表结构分别如下：</p>
<div class="hl-surround" style="border: 1px solid #c3ced9; margin: 0px 0px 5px; padding: 0px; overflow: auto; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Fixedsys,'BitStream Vera Sans Mono','Courier New',Courier,monospace; color: #111111; background-color: #f9fbfc; width: auto; height: auto; text-align: left;">
<div class="hl-main" style="border-width: 0px; margin: 0px; padding: 6px 24px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #111111; line-height: 25px; background-color: transparent;"><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">sky</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">@</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">localhost</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span>:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">example</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">01</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">48</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">21</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">&amp;</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">gt</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">;<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">show</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">create</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">table</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">A</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">\</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">G</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
***************************<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">1.</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">row</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span>***************************<br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">Table</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">A</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">Create</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">Table</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">CREATE</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">TABLE</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">A</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: olive;">(</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">c1</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">int</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: olive;">(</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">11</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: olive;">)</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">NOT</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">NULL</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">default</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">&#8216;</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: red;">0</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">&#8216;</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">,<br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">c2</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">char</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: olive;">(</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">2</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: olive;">)</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">default</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">NULL</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">,<br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">c3</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">varchar</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: olive;">(</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">16</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: olive;">)</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">default</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">NULL</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">,<br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">c4</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">datetime</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">default</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">NULL</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">,<br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">PRIMARY</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">KEY</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"> <span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: olive;">(</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">c1</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: olive;">)</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: olive;">)</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">ENGINE</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">=</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">MyISAM</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">DEFAULT</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">CHARSET</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">=</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">utf8</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"></p>
<p></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">sky</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">@</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">localhost</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span>:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">example</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">01</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">48</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">32</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">&amp;</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">gt</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">;<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">show</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">create</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">table</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">B</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">\</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">G</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
***************************<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">1.</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">row</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span>***************************<br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">Table</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">B</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">Create</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">Table</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">CREATE</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">TABLE</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">B</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: olive;">(</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">c1</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">int</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: olive;">(</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">11</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: olive;">)</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">NOT</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">NULL</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">default</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">&#8216;</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: red;">0</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">&#8216;</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">,<br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">c2</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">char</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: olive;">(</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">2</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: olive;">)</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">default</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">NULL</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">,<br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">c3</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">varchar</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: olive;">(</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">16</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: olive;">)</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">default</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">NULL</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">,<br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">PRIMARY</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">KEY</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"> <span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: olive;">(</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">c1</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: olive;">)</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">,<br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">KEY</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">B_c2_ind</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: olive;">(</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">c2</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #8b0000;">`</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: olive;">)</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: olive;">)</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">ENGINE</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">=</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">MyISAM</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">DEFAULT</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">CHARSET</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">=</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">utf8</span></div>
</div>
<p style="border-width: 0px; margin: 0px 0px 10px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #111111; line-height: 1.7;">1、利用有序索引进行排序，实际上就是当我们 Query 的 ORDER BY 条件和 Query 的执行计划中所利用的 Index 的索引键（或前面几个索引键）完全一致，且索引访问方式为 rang、 ref 或者 index 的时候，MySQL 可以利用索引顺序而直接取得已经排好序的数据。这种方式的 ORDER BY 基本上可以说是最优的排序方式了，因为 MySQL 不需要进行实际的排序操作。</p>
<p style="border-width: 0px; margin: 0px 0px 10px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #111111; line-height: 1.7;">假设我们在Table A 和 B 上执行如下SQL：</p>
<div class="hl-surround" style="border: 1px solid #c3ced9; margin: 0px 0px 5px; padding: 0px; overflow: auto; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Fixedsys,'BitStream Vera Sans Mono','Courier New',Courier,monospace; color: #111111; background-color: #f9fbfc; width: auto; height: auto; text-align: left;">
<div class="hl-main" style="border-width: 0px; margin: 0px; padding: 6px 24px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #111111; line-height: 25px; background-color: transparent;"><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">sky</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">@</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">localhost</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span>:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">example</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">01</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">44</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">28</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">&amp;</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">gt</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">;<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">EXPLAIN</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">SELECT</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">A</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">.*<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">FROM</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">A</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">,</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">B</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
-&amp;</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">gt</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">;<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">WHERE</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">A</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">.</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">c1</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span>&amp;</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">gt</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">;<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">2</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">AND</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">A</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">.</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">c2</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span>&amp;</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">lt</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">;<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">5</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">AND</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">A</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">.</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">c2</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span>=<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">B</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">.</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">c2</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">ORDER</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">BY</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">A</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">.</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">c1</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">\</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">G</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
***************************<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">1.</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">row</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span>***************************<br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">id</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">1</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">select_type</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">SIMPLE</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">table</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">A</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">type</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">range</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">possible_keys</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">PRIMARY</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">key</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">PRIMARY</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">key_len</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">4</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">ref</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">NULL</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">rows</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">3</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">Extra</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">Using</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">where</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
***************************<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">2.</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">row</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span>***************************<br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">id</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">1</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">select_type</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">SIMPLE</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">table</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">B</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">type</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">ref</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">possible_keys</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">B_c2_ind</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">key</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">B_c2_ind</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">key_len</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">7</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">ref</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">example</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">.</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">A</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">.</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">c2</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">rows</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">2</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">Extra</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">Using</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">where</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">;<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">Using</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">index</span></div>
</div>
<p style="border-width: 0px; margin: 0px 0px 10px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #111111; line-height: 1.7;">我们通过执行计划可以看出，MySQL实际上并没有进行实际的排序操作，实际上其整个执行过程如下图所示：</p>
<p style="border-width: 0px; margin: 0px 0px 10px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #111111; line-height: 1.7;"><img class="aligncenter size-full wp-image-319" style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #111111;" title="order_by_no_sort" src="http://www.jianzhaoyang.com/wp-content/uploads/2008/11/order_by_no_sort.jpg" alt="" width="500" height="350" /></p>
<p style="border-width: 0px; margin: 0px 0px 10px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #111111; line-height: 1.7;">2、通过相应的排序算法，将取得的数据在内存中进行排序方式，MySQL 比需要将数据在内存中进行排序，所使用的内存区域也就是我们通过 sort_buffer_size 系统变量所设置的排序区。这个排序区是每个 Thread 独享的，所以说可能在同一时刻在 MySQL 中可能存在多个 sort buffer 内存区域。</p>
<p style="border-width: 0px; margin: 0px 0px 10px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #111111; line-height: 1.7;">第二种方式在 MySQL Query Optimizer 所给出的执行计划（通过 EXPLAIN 命令查看）中被称为 filesort。在这种方式中，主要是由于没有可以利用的有序索引取得有序的数据，MySQL只能通过将取得的数据在内存中进行排序然后再将数据返回给客户端。在 MySQL 中 filesort 的实现算法实际上是有两种的，一种是首先根据相应的条件取出相应的排序字段和可以直接定位行数据的行指针信息，然后在 sort buffer 中进行排序。另外一种是一次性取出满足条件行的所有字段，然后在 sort buffer 中进行排序。</p>
<p style="border-width: 0px; margin: 0px 0px 10px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #111111; line-height: 1.7;">在 MySQL4.1 版本之前只有第一种排序算法，第二种算法是从 MySQL4.1开始的改进算法，主要目的是为了减少第一次算法中需要两次访问表数据的 IO 操作，将两次变成了一次，但相应也会耗用更多的 sort buffer 空间。当然，MySQL4.1开始的以后所有版本同时也支持第一种算法，MySQL 主要通过比较我们所设定的系统参数 max_length_for_sort_data 的大小和 Query 语句所取出的字段类型大小总和来判定需要使用哪一种排序算法。如果 max_length_for_sort_data 更大，则使用第二种优化后的算法，反之使用第一种算法。所以如果希望 ORDER BY 操作的效率尽可能的高，一定要主义 max_length_for_sort_data 参数的设置。曾经就有同事的数据库出现大量的排序等待，造成系统负载很高，而且响应时间变得很长，最后查出正是因为 MySQL 使用了传统的第一种排序算法而导致，在加大了 max_length_for_sort_data 参数值之后，系统负载马上得到了大的缓解，响应也快了很多。</p>
<p style="border-width: 0px; margin: 0px 0px 10px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #111111; line-height: 1.7;">我们再看看 MySQL 需要使用 filesort 实现排序的实例。</p>
<p style="border-width: 0px; margin: 0px 0px 10px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #111111; line-height: 1.7;">假设我们改变一下我们的 Query，换成通过A.c2来排序，再看看情况：</p>
<div class="hl-surround" style="border: 1px solid #c3ced9; margin: 0px 0px 5px; padding: 0px; overflow: auto; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Fixedsys,'BitStream Vera Sans Mono','Courier New',Courier,monospace; color: #111111; background-color: #f9fbfc; width: auto; height: auto; text-align: left;">
<div class="hl-main" style="border-width: 0px; margin: 0px; padding: 6px 24px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #111111; line-height: 25px; background-color: transparent;"><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">sky</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">@</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">localhost</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span>:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">example</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">01</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">54</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">23</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">&amp;</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">gt</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">;<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">EXPLAIN</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">SELECT</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">A</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">.*<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">FROM</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">A</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">,</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">B</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
-&amp;</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">gt</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">;<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">WHERE</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">A</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">.</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">c1</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span>&amp;</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">gt</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">;<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">2</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">AND</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">A</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">.</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">c2</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span>&amp;</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">lt</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">;<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">5</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">AND</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">A</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">.</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">c2</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span>=<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">B</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">.</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">c2</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">ORDER</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">BY</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">A</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">.</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">c2</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">\</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">G</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
***************************<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">1.</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">row</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span>***************************<br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">id</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">1</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">select_type</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">SIMPLE</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">table</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">A</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">type</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">range</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">possible_keys</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">PRIMARY</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">key</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">PRIMARY</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">key_len</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">4</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">ref</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">NULL</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">rows</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">3</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">Extra</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">Using</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">where</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">;<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">Using</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">filesort</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
***************************<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">2.</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">row</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span>***************************<br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">id</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">1</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">select_type</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">SIMPLE</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">table</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">B</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">type</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">ref</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">possible_keys</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">B_c2_ind</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">key</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">B_c2_ind</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">key_len</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">7</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">ref</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">example</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">.</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">A</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">.</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">c2</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">rows</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">2</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">Extra</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">Using</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">where</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">;<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">Using</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">index</span></div>
</div>
<p style="border-width: 0px; margin: 0px 0px 10px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #111111; line-height: 1.7;">MySQL 从 Table A 中取出了符合条件的数据，由于取得的数据并不满足 ORDER BY 条件，所以 MySQL 进行了 filesort 操作，其整个执行过程如下图所示：</p>
<p style="border-width: 0px; margin: 0px 0px 10px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #111111; line-height: 1.7;"><img class="aligncenter size-full wp-image-320" style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #111111;" title="order_by_filesort" src="http://www.jianzhaoyang.com/wp-content/uploads/2008/11/order_by_filesort.jpg" alt="" width="500" height="350" /></p>
<p style="border-width: 0px; margin: 0px 0px 10px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #111111; line-height: 1.7;">在 MySQL 中，filesort 操作还有一个比较奇怪的限制，那就是其数据源必须是来源于一个 Table，所以，如果我们的排序数据如果是两个（或者更多个） Table 通过 Join所得出的，那么 MySQL 必须通过先创建一个临时表（Temporary Table），然后再将此临时表的数据进行排序，如下例所示：</p>
<div class="hl-surround" style="border: 1px solid #c3ced9; margin: 0px 0px 5px; padding: 0px; overflow: auto; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Fixedsys,'BitStream Vera Sans Mono','Courier New',Courier,monospace; color: #111111; background-color: #f9fbfc; width: auto; height: auto; text-align: left;">
<div class="hl-main" style="border-width: 0px; margin: 0px; padding: 6px 24px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #111111; line-height: 25px; background-color: transparent;"><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">sky</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">@</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">localhost</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span>:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">example</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">02</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">46</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">15</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">&amp;</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">gt</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">;<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">explain</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">select</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">A</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">.*<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">from</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">A</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">,</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">B</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
-&amp;</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">gt</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">;<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">where</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">A</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">.</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">c1</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span>&amp;</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">gt</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">;<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">2</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">and</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">A</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">.</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">c2</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span>&amp;</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">lt</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">;<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">5</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">and</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">A</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">.</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">c2</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span>=<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">B</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">.</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">c2</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">order</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">by</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">B</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">.</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">c3</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">\</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">G</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
***************************<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">1.</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">row</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span>***************************<br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">id</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">1</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">select_type</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">SIMPLE</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">table</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">A</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">type</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">range</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">possible_keys</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">PRIMARY</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">key</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">PRIMARY</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">key_len</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">4</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">ref</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">NULL</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">rows</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">3</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">Extra</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">Using</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">where</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">;<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">Using</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">temporary</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">;<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">Using</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">filesort</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
***************************<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">2.</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">row</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span>***************************<br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">id</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">1</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">select_type</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">SIMPLE</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">table</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">B</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">type</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">ref</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">possible_keys</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">B_c2_ind</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">key</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">B_c2_ind</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">key_len</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">7</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">ref</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">example</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">.</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">A</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">.</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">c2</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">rows</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: maroon;">2</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><br />
</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: blue;">Extra</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;">:<span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">Using</span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: gray;"><span class="Apple-converted-space"> </span></span><span style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: green;">where</span></div>
</div>
<p style="border-width: 0px; margin: 0px 0px 10px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #111111; line-height: 1.7;">这个执行计划的输出还是有点奇怪的，不知道为什么，MySQL Query Optimizer 将 “Using temporary” 过程显示在第一行对 Table A 的操作中，难道只是为让执行计划的输出少一行？</p>
<p style="border-width: 0px; margin: 0px 0px 10px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #111111; line-height: 1.7;">实际执行过程应该是如下图所示：<br />
<img class="aligncenter size-full wp-image-321" style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #111111;" title="order_by_tmp_table_filesort" src="http://www.jianzhaoyang.com/wp-content/uploads/2008/11/order_by_tmp_table_filesort.jpg" alt="" width="500" height="350" />
</p>
<p style="border-width: 0px; margin: 0px 0px 10px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #111111; line-height: 1.7;"><span class="Apple-style-span" style="border-collapse: separate; color: #111111; font-family: Tahoma; font-size: 14px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px;"><span class="Apple-style-span" style="color: #939393;">作者：<a style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #939393; text-decoration: none;" href="http://www.jianzhaoyang.com/">Sky.Jian</a></span></span></p>
<p style="border-width: 0px; margin: 0px 0px 10px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #111111; line-height: 1.7;"><span class="Apple-style-span" style="border-collapse: separate; color: #111111; font-family: Tahoma; font-size: 14px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px;"><span class="Apple-style-span" style="color: #939393;">链接：<a style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #939393; text-decoration: none;" href="http://www.jianzhaoyang.com/database/mysql_order_by_implement">http://www.jianzhaoyang.com/database/mysql_order_by_implement</a><span class="Apple-converted-space"><br />
</span></span></span></p>
<p></span></span></p>
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		<title>MySQL内存使用-线程独享</title>
		<link>http://226617.cn/archives/583.htm</link>
		<comments>http://226617.cn/archives/583.htm#comments</comments>
		<pubDate>Wed, 22 Apr 2009 07:37:10 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[mysql相关]]></category>
		<category><![CDATA[mysql]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=583</guid>
		<description><![CDATA[对于任何一个数据库管理系统来说，内存的分配使用绝对可以算的上是其核心之一了，所以很多希望更为深入了解某数据库管理系统的人，都会希望一窥究竟，我也不例外。 从内存的使用方式M... ]]></description>
			<content:encoded><![CDATA[<p style="border-width: 0px; margin: 0px 0px 10px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #111111; line-height: 1.7;">对于任何一个数据库管理系统来说，内存的分配使用绝对可以算的上是其核心之一了，所以很多希望更为深入了解某数据库管理系统的人，都会希望一窥究竟，我也不例外。</p>
<p style="border-width: 0px; margin: 0px 0px 10px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #111111; line-height: 1.7;">从内存的使用方式MySQL 数据库的内存使用主要分为以下两类</p>
<ul style="border-width: 0px; margin: 0px 0px 12px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #111111;">
<li style="border-width: 0px; margin: 0px 0px 2px 25px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #111111; line-height: 22px;">线程独享内存</li>
<li style="border-width: 0px; margin: 0px 0px 2px 25px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #111111; line-height: 22px;">全局共享内存</li>
</ul>
<p style="border-width: 0px; margin: 0px 0px 10px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #111111; line-height: 1.7;">今天这篇文章暂时先分析 MySQL 中主要的 “线程独享内存” 的。</p>
<p style="border-width: 0px; margin: 0px 0px 10px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #111111; line-height: 1.7;">在 MySQL 中，线程独享内存主要用于各客户端连接线程存储各种操作的独享数据，如线程栈信息，分组排序操作，数据读写缓冲，结果集暂存等等，而且大多数可以通过相关参数来控制内存的使用量。</p>
<p style="border-width: 0px; margin: 0px 0px 10px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #111111; line-height: 1.7;"><strong>线程栈信息使用内存(thread_stack)</strong>：主要用来存放每一个线程自身的标识信息，如线程id，线程运行时基本信息等等，我们可以通过 thread_stack 参数来设置为每一个线程栈分配多大的内存。</p>
<p style="border-width: 0px; margin: 0px 0px 10px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #111111; line-height: 1.7;"><strong>排序使用内存(sort_buffer_size)</strong>：MySQL 用此内存区域进行排序操作（filesort），完成客户端的排序请求。当我们设置的排序区缓存大小无法满足排序实际所需内存的时候，MySQL 会将数据写入磁盘文件来完成排序。由于磁盘和内存的读写性能完全不在一个数量级，所以sort_buffer_size参数对排序操作的性能影响绝对不可小视。排序操作的实现原理请参考：<a style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #46a8c8; text-decoration: none;" href="http://www.jianzhaoyang.com/database/mysql_order_by_implement">MySQL Order By 的实现分析</a>。</p>
<p style="border-width: 0px; margin: 0px 0px 10px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #111111; line-height: 1.7;"><strong>Join操作使用内存(join_buffer_size)</strong>：应用程序经常会出现一些两表（或多表）Join的操作需求，MySQL在完成某些 Join 需求的时候（all/index join），为了减少参与Join的“被驱动表”的读取次数以提高性能，需要使用到 Join Buffer 来协助完成 Join操作（具体 Join 实现算法请参考：<a style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #46a8c8; text-decoration: none;" href="http://www.jianzhaoyang.com/database/mysql_join_buffer_nested_loop_implement">MySQL 中的 Join 基本实现原理</a>）。当 Join Buffer 太小，MySQL 不会将该 Buffer 存入磁盘文件，而是先将Join Buffer中的结果集与需要 Join 的表进行 Join 操作，然后清空 Join Buffer 中的数据，继续将剩余的结果集写入此 Buffer 中，如此往复。这势必会造成被驱动表需要被多次读取，成倍增加 IO 访问，降低效率。</p>
<p style="border-width: 0px; margin: 0px 0px 10px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #111111; line-height: 1.7;"><strong>顺序读取数据缓冲区使用内存(read_buffer_size)</strong>：这部分内存主要用于当需要顺序读取数据的时候，如无发使用索引的情况下的全表扫描，全索引扫描等。在这种时候，MySQL 按照数据的存储顺序依次读取数据块，每次读取的数据快首先会暂存在read_buffer_size中，当 buffer 空间被写满或者全部数据读取结束后，再将buffer中的数据返回给上层调用者，以提高效率。</p>
<p style="border-width: 0px; margin: 0px 0px 10px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #111111; line-height: 1.7;"><strong>随机读取数据缓冲区使用内存(read_rnd_buffer_size)</strong>：和顺序读取相对应，当 MySQL 进行非顺序读取（随机读取）数据块的时候，会利用这个缓冲区暂存读取的数据。如根据索引信息读取表数据，根据排序后的结果集与表进行Join等等。总的来说，就是当数据块的读取需要满足一定的顺序的情况下，MySQL 就需要产生随机读取，进而使用到 read_rnd_buffer_size 参数所设置的内存缓冲区。</p>
<p style="border-width: 0px; margin: 0px 0px 10px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #111111; line-height: 1.7;"><strong>连接信息及返回客户端前结果集暂存使用内存(net_buffer_size)</strong>：这部分用来存放客户端连接线程的连接信息和返回客户端的结果集。当 MySQL 开始产生可以返回的结果集，会在通过网络返回给客户端请求线程之前，会先暂存在通过 net_buffer_size 所设置的缓冲区中，等满足一定大小的时候才开始向客户端发送，以提高网络传输效率。不过，net_buffer_size 参数所设置的仅仅只是该缓存区的初始化大小，MySQL 会根据实际需要自行申请更多的内存以满足需求，但最大不会超过 max_allowed_packet 参数大小。</p>
<p style="border-width: 0px; margin: 0px 0px 10px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #111111; line-height: 1.7;"><strong>批量插入暂存使用内存(bulk_insert_buffer_size)：</strong>当我们使用如 insert … values(…),(…),(…)… 的方式进行批量插入的时候，MySQL 会先将提交的数据放如一个缓存空间中，当该缓存空间被写满或者提交完所有数据之后，MySQL 才会一次性将该缓存空间中的数据写入数据库并清空缓存。此外，当我们进行 LOAD DATA INFILE 操作来将文本文件中的数据 Load 进数据库的时候，同样会使用到此缓冲区。</p>
<p style="border-width: 0px; margin: 0px 0px 10px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #111111; line-height: 1.7;"><strong>临时表使用内存(tmp_table_size)：</strong>当我们进行一些特殊操作如需要使用临时表才能完成的 Order By，Group By 等等，MySQL 可能需要使用到临时表。当我们的临时表较小（小于 tmp_table_size 参数所设置的大小）的时候，MySQL 会将临时表创建成内存临时表，只有当 tmp_table_size 所设置的大小无法装下整个临时表的时候，MySQL 才会将该表创建成 MyISAM 存储引擎的表存放在磁盘上。不过，当另一个系统参数 max_heap_table_size 的大小还小于 tmp_table_size 的时候，MySQL 将使用 max_heap_table_size 参数所设置大小作为最大的内存临时表大小，而忽略 tmp_table_size 所设置的值。而且 tmp_table_size 参数从 MySQL 5.1.2 才开始有，之前一直使用 max_heap_table_size。</p>
<p style="border-width: 0px; margin: 0px 0px 10px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #111111; line-height: 1.7;">上面所列举的 MySQL 线程独享内存仅仅只是所有线程独享内存中的部分，并不是全部，选择的原则是可能对 MySQL 的性能产生较大的影响，且可以通过系统参数进行调节。</p>
<p style="border-width: 0px; margin: 0px 0px 10px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #111111; line-height: 1.7;">由于以上内存都是线程独享，极端情况下的内存总体使用量将是所有连接线程的总倍数。所以各位朋友在设置过程中一定要谨慎，切不可为了提升性能就盲目的增大各参数值，避免因为内存不够而产生 Out Of Memory 异常或者是严重的 Swap 交换反而降低整体性能。</p>
<p><span class="Apple-style-span" style="border-collapse: separate; color: #111111; font-family: Tahoma; font-size: 14px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px;"><span class="Apple-style-span" style="color: #939393;">作者：<a style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #939393; text-decoration: none;" href="http://www.jianzhaoyang.com/">Sky.Jian<br />
</a></span></span><span class="Apple-style-span" style="border-collapse: separate; color: #111111; font-family: Tahoma; font-size: 14px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px;"><span class="Apple-style-span" style="color: #939393;">链接：<a style="border-width: 0px; margin: 0px; padding: 0px; outline-width: 0px; font-weight: normal; font-size: 14px; font-family: Tahoma,Arial,Helvetica,sans-serif; color: #939393; text-decoration: none;" href="http://www.jianzhaoyang.com/database/mysql-memory-thread-private">http://www.jianzhaoyang.com/database/mysql-memory-thread-private</a></span></span></p>
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		<title>华为交换机的端口限速</title>
		<link>http://226617.cn/archives/578.htm</link>
		<comments>http://226617.cn/archives/578.htm#comments</comments>
		<pubDate>Tue, 21 Apr 2009 12:37:43 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[硬件相关]]></category>
		<category><![CDATA[quidway]]></category>
		<category><![CDATA[S5024G]]></category>
		<category><![CDATA[交换机]]></category>
		<category><![CDATA[华为]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=578</guid>
		<description><![CDATA[最近在电信idc的宽频流量有点涨，所以想把一些非关键应用的流量通过端口限速限制一下。 限速的这台交换机是S5024G，其实大部分华为交换机都通用，只是细粒度不一样用得时候 ? 看看单位值... ]]></description>
			<content:encoded><![CDATA[<p>最近在电信idc的宽频流量有点涨，所以想把一些非关键应用的流量通过端口限速限制一下。<br />
限速的这台交换机是S5024G，其实大部分华为交换机都通用，只是细粒度不一样用得时候 ? 看看单位值就行。</p>
<p>操作步骤：<br />
进入交换机console</p>
<p>&lt;S5024G-1&gt;system-view<br />
Enter system view, return to user view with Ctrl+Z.<br />
[S5024G-1]interface GigabitEthernet0/2<br />
[S5024G-1-GigabitEthernet0/2]line-rate ?<br />
INTEGER&lt;1-1000&gt; Target rate(Mbps)</p>
<p>这里line-rate单位是Mbps，直接输入数字1-1000就代表1Mbps-1000Mbps，我们限制为50Mbps。</p>
<p>[S5024G-1-GigabitEthernet0/2]line-rate 50</p>
<p>这里要注意 line-rate 只能对交换机端口的出流量进行限速。<br />
如果要对端口入流量限速的话就必须要用traffic-limit方式，使用traffic-limit则必须要用acl匹配。</p>
<p>[S5024G-1]acl number 4000<br />
[S5024G-1-acl-link-4000]rule permit ingress any egress any</p>
<p>然后再在端口里面添加traffic-limit，这里对入方向限速50Mbps</p>
<p>[S5024G-1-GigabitEthernet0/2]traffic-limit inbound link-group 4000 50 exceed drop</p>
<p>这样就ok了。</p>
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		<title>iis下面php getenv(&#8216;HTTP_X_FORWARDED_FOR&#8217;)取不到ip</title>
		<link>http://226617.cn/archives/576.htm</link>
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		<pubDate>Thu, 16 Apr 2009 09:07:08 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[php相关]]></category>
		<category><![CDATA[windows相关]]></category>
		<category><![CDATA[php]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=576</guid>
		<description><![CDATA[环境是win2003 iis6 php(isapi) 应用是个dz，最近在上了cdn后发现用户过来的ip都是squid服务器的地址，看了下dz的源代码 1 2 3 4 5 6 7 8 9 if&#40;getenv&#40;'HTTP_CLIENT_IP'&#41; &#38;&#38; strcasecmp&#40;getenv&#40;'HTTP_CLI... ]]></description>
			<content:encoded><![CDATA[<p>环境是win2003 iis6 php(isapi)<br />
应用是个dz，最近在上了cdn后发现用户过来的ip都是squid服务器的地址，看了下dz的源代码</p>

<div class="wp_syntax"><table><tr><td class="line_numbers"><pre>1
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</pre></td><td class="code"><pre class="php" style="font-family:monospace;"><span style="color: #b1b100;">if</span><span style="color: #009900;">&#40;</span><span style="color: #990000;">getenv</span><span style="color: #009900;">&#40;</span><span style="color: #0000ff;">'HTTP_CLIENT_IP'</span><span style="color: #009900;">&#41;</span> <span style="color: #339933;">&amp;&amp;</span> <span style="color: #990000;">strcasecmp</span><span style="color: #009900;">&#40;</span><span style="color: #990000;">getenv</span><span style="color: #009900;">&#40;</span><span style="color: #0000ff;">'HTTP_CLIENT_IP'</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">,</span> <span style="color: #0000ff;">'unknown'</span><span style="color: #009900;">&#41;</span><span style="color: #009900;">&#41;</span> <span style="color: #009900;">&#123;</span>
	<span style="color: #000088;">$onlineip</span> <span style="color: #339933;">=</span> <span style="color: #990000;">getenv</span><span style="color: #009900;">&#40;</span><span style="color: #0000ff;">'HTTP_CLIENT_IP'</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">;</span>
<span style="color: #009900;">&#125;</span> <span style="color: #b1b100;">elseif</span><span style="color: #009900;">&#40;</span><span style="color: #990000;">getenv</span><span style="color: #009900;">&#40;</span><span style="color: #0000ff;">'HTTP_X_FORWARDED_FOR'</span><span style="color: #009900;">&#41;</span> <span style="color: #339933;">&amp;&amp;</span> <span style="color: #990000;">strcasecmp</span><span style="color: #009900;">&#40;</span><span style="color: #990000;">getenv</span><span style="color: #009900;">&#40;</span><span style="color: #0000ff;">'HTTP_X_FORWARDED_FOR'</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">,</span> <span style="color: #0000ff;">'unknown'</span><span style="color: #009900;">&#41;</span><span style="color: #009900;">&#41;</span> <span style="color: #009900;">&#123;</span>
	<span style="color: #000088;">$onlineip</span> <span style="color: #339933;">=</span> <span style="color: #990000;">getenv</span><span style="color: #009900;">&#40;</span><span style="color: #0000ff;">'HTTP_X_FORWARDED_FOR'</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">;</span>
<span style="color: #009900;">&#125;</span> <span style="color: #b1b100;">elseif</span><span style="color: #009900;">&#40;</span><span style="color: #990000;">getenv</span><span style="color: #009900;">&#40;</span><span style="color: #0000ff;">'REMOTE_ADDR'</span><span style="color: #009900;">&#41;</span> <span style="color: #339933;">&amp;&amp;</span> <span style="color: #990000;">strcasecmp</span><span style="color: #009900;">&#40;</span><span style="color: #990000;">getenv</span><span style="color: #009900;">&#40;</span><span style="color: #0000ff;">'REMOTE_ADDR'</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">,</span> <span style="color: #0000ff;">'unknown'</span><span style="color: #009900;">&#41;</span><span style="color: #009900;">&#41;</span> <span style="color: #009900;">&#123;</span>
	<span style="color: #000088;">$onlineip</span> <span style="color: #339933;">=</span> <span style="color: #990000;">getenv</span><span style="color: #009900;">&#40;</span><span style="color: #0000ff;">'REMOTE_ADDR'</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">;</span>
<span style="color: #009900;">&#125;</span> <span style="color: #b1b100;">elseif</span><span style="color: #009900;">&#40;</span><span style="color: #990000;">isset</span><span style="color: #009900;">&#40;</span><span style="color: #000088;">$_SERVER</span><span style="color: #009900;">&#91;</span><span style="color: #0000ff;">'REMOTE_ADDR'</span><span style="color: #009900;">&#93;</span><span style="color: #009900;">&#41;</span> <span style="color: #339933;">&amp;&amp;</span> <span style="color: #000088;">$_SERVER</span><span style="color: #009900;">&#91;</span><span style="color: #0000ff;">'REMOTE_ADDR'</span><span style="color: #009900;">&#93;</span> <span style="color: #339933;">&amp;&amp;</span> <span style="color: #990000;">strcasecmp</span><span style="color: #009900;">&#40;</span><span style="color: #000088;">$_SERVER</span><span style="color: #009900;">&#91;</span><span style="color: #0000ff;">'REMOTE_ADDR'</span><span style="color: #009900;">&#93;</span><span style="color: #339933;">,</span> <span style="color: #0000ff;">'unknown'</span><span style="color: #009900;">&#41;</span><span style="color: #009900;">&#41;</span> <span style="color: #009900;">&#123;</span>
	<span style="color: #000088;">$onlineip</span> <span style="color: #339933;">=</span> <span style="color: #000088;">$_SERVER</span><span style="color: #009900;">&#91;</span><span style="color: #0000ff;">'REMOTE_ADDR'</span><span style="color: #009900;">&#93;</span><span style="color: #339933;">;</span>
<span style="color: #009900;">&#125;</span></pre></td></tr></table></div>

<p>对比了下另外一台linux的机器发现是可以取到的。<br />
于是用_SERVER["HTTP_X_FORWARDED_FOR"]试了试是可以取到用户ip的，难道在windows下面不能用getenv？<br />
最后略微修改了下dz的代码搞定了</p>

<div class="wp_syntax"><table><tr><td class="line_numbers"><pre>1
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</pre></td><td class="code"><pre class="php" style="font-family:monospace;"><span style="color: #b1b100;">if</span><span style="color: #009900;">&#40;</span><span style="color: #990000;">getenv</span><span style="color: #009900;">&#40;</span><span style="color: #0000ff;">'HTTP_CLIENT_IP'</span><span style="color: #009900;">&#41;</span> <span style="color: #339933;">&amp;&amp;</span> <span style="color: #990000;">strcasecmp</span><span style="color: #009900;">&#40;</span><span style="color: #990000;">getenv</span><span style="color: #009900;">&#40;</span><span style="color: #0000ff;">'HTTP_CLIENT_IP'</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">,</span> <span style="color: #0000ff;">'unknown'</span><span style="color: #009900;">&#41;</span><span style="color: #009900;">&#41;</span> <span style="color: #009900;">&#123;</span>
	<span style="color: #000088;">$onlineip</span> <span style="color: #339933;">=</span> <span style="color: #990000;">getenv</span><span style="color: #009900;">&#40;</span><span style="color: #0000ff;">'HTTP_CLIENT_IP'</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">;</span>
<span style="color: #009900;">&#125;</span> <span style="color: #b1b100;">elseif</span><span style="color: #009900;">&#40;</span><span style="color: #990000;">getenv</span><span style="color: #009900;">&#40;</span><span style="color: #0000ff;">'HTTP_X_FORWARDED_FOR'</span><span style="color: #009900;">&#41;</span> <span style="color: #339933;">&amp;&amp;</span> <span style="color: #990000;">strcasecmp</span><span style="color: #009900;">&#40;</span><span style="color: #990000;">getenv</span><span style="color: #009900;">&#40;</span><span style="color: #0000ff;">'HTTP_X_FORWARDED_FOR'</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">,</span> <span style="color: #0000ff;">'unknown'</span><span style="color: #009900;">&#41;</span><span style="color: #009900;">&#41;</span> <span style="color: #009900;">&#123;</span>
	<span style="color: #000088;">$onlineip</span> <span style="color: #339933;">=</span> <span style="color: #990000;">getenv</span><span style="color: #009900;">&#40;</span><span style="color: #0000ff;">'HTTP_X_FORWARDED_FOR'</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">;</span>
<span style="color: #009900;">&#125;</span> <span style="color: #b1b100;">elseif</span><span style="color: #009900;">&#40;</span><span style="color: #000088;">$_SERVER</span><span style="color: #009900;">&#91;</span><span style="color: #0000ff;">&quot;HTTP_X_FORWARDED_FOR&quot;</span><span style="color: #009900;">&#93;</span> <span style="color: #339933;">&amp;&amp;</span> <span style="color: #990000;">strcasecmp</span><span style="color: #009900;">&#40;</span><span style="color: #000088;">$_SERVER</span><span style="color: #009900;">&#91;</span><span style="color: #0000ff;">&quot;HTTP_X_FORWARDED_FOR&quot;</span><span style="color: #009900;">&#93;</span><span style="color: #339933;">,</span> <span style="color: #0000ff;">'unknown'</span><span style="color: #009900;">&#41;</span><span style="color: #009900;">&#41;</span> <span style="color: #009900;">&#123;</span>
	<span style="color: #000088;">$onlineip</span> <span style="color: #339933;">=</span> <span style="color: #000088;">$_SERVER</span><span style="color: #009900;">&#91;</span><span style="color: #0000ff;">&quot;HTTP_X_FORWARDED_FOR&quot;</span><span style="color: #009900;">&#93;</span><span style="color: #339933;">;</span>
<span style="color: #009900;">&#125;</span> <span style="color: #b1b100;">elseif</span><span style="color: #009900;">&#40;</span><span style="color: #990000;">getenv</span><span style="color: #009900;">&#40;</span><span style="color: #0000ff;">'REMOTE_ADDR'</span><span style="color: #009900;">&#41;</span> <span style="color: #339933;">&amp;&amp;</span> <span style="color: #990000;">strcasecmp</span><span style="color: #009900;">&#40;</span><span style="color: #990000;">getenv</span><span style="color: #009900;">&#40;</span><span style="color: #0000ff;">'REMOTE_ADDR'</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">,</span> <span style="color: #0000ff;">'unknown'</span><span style="color: #009900;">&#41;</span><span style="color: #009900;">&#41;</span> <span style="color: #009900;">&#123;</span>
	<span style="color: #000088;">$onlineip</span> <span style="color: #339933;">=</span> <span style="color: #990000;">getenv</span><span style="color: #009900;">&#40;</span><span style="color: #0000ff;">'REMOTE_ADDR'</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">;</span>
<span style="color: #009900;">&#125;</span> <span style="color: #b1b100;">elseif</span><span style="color: #009900;">&#40;</span><span style="color: #990000;">isset</span><span style="color: #009900;">&#40;</span><span style="color: #000088;">$_SERVER</span><span style="color: #009900;">&#91;</span><span style="color: #0000ff;">'REMOTE_ADDR'</span><span style="color: #009900;">&#93;</span><span style="color: #009900;">&#41;</span> <span style="color: #339933;">&amp;&amp;</span> <span style="color: #000088;">$_SERVER</span><span style="color: #009900;">&#91;</span><span style="color: #0000ff;">'REMOTE_ADDR'</span><span style="color: #009900;">&#93;</span> <span style="color: #339933;">&amp;&amp;</span> <span style="color: #990000;">strcasecmp</span><span style="color: #009900;">&#40;</span><span style="color: #000088;">$_SERVER</span><span style="color: #009900;">&#91;</span><span style="color: #0000ff;">'REMOTE_ADDR'</span><span style="color: #009900;">&#93;</span><span style="color: #339933;">,</span> <span style="color: #0000ff;">'unknown'</span><span style="color: #009900;">&#41;</span><span style="color: #009900;">&#41;</span> <span style="color: #009900;">&#123;</span>
	<span style="color: #000088;">$onlineip</span> <span style="color: #339933;">=</span> <span style="color: #000088;">$_SERVER</span><span style="color: #009900;">&#91;</span><span style="color: #0000ff;">'REMOTE_ADDR'</span><span style="color: #009900;">&#93;</span><span style="color: #339933;">;</span>
<span style="color: #009900;">&#125;</span></pre></td></tr></table></div>

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		</item>
		<item>
		<title>电信EVDO 3G无线宽带试用</title>
		<link>http://226617.cn/archives/569.htm</link>
		<comments>http://226617.cn/archives/569.htm#comments</comments>
		<pubDate>Wed, 15 Apr 2009 12:37:45 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[只谈心情]]></category>
		<category><![CDATA[3G]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=569</guid>
		<description><![CDATA[其实半个多月前就体验过EVDO了，同事去采访发布会的时候带回来过一个，那次纯粹就是安装上网流程化体验了下，记得是个华为的设备。 这次单位领导正好把以前的老的cmda上网卡去换了个回... ]]></description>
			<content:encoded><![CDATA[<p>其实半个多月前就体验过EVDO了，同事去采访发布会的时候带回来过一个，那次纯粹就是安装上网流程化体验了下，记得是个华为的设备。</p>
<p>这次单位领导正好把以前的老的cmda上网卡去换了个回来，由于老婆童装店里也正在考虑搞个无线上网省的装宽带了，所以带回来试了试信号顺便试用下。</p>
<p>这次的拿回来的2个是中兴 AC560的设备，东西蛮好看就个u盘大小，上面除了uim卡插槽外还有个tf卡插槽，能当读卡器用，貌似还有2喇叭。做工不错<br />
<a href="http://226617.cn/wp-content/uploads/2009/04/ztx-ac560.jpg" onclick="return hs.expand(this);" class="highslide-image"><img src="http://226617.cn/wp-content/uploads/2009/04/ztx-ac560.jpg" alt="image" title="Click to enlarge" /></a><br />
由于有了上次安装的经验，所以直接就像u盘那样插进usb口，电脑提示发现新硬件，其实是个u盘，里面就是上网卡的驱动，现在这设计蛮好的省的光盘了。一路驱动装完后出现了拨号界面，直接选3G，顺利上网，连接速率3.1M。<br />
<a href="http://226617.cn/wp-content/uploads/2009/04/3g-1.jpg" onclick="return hs.expand(this);" class="highslide-image"><img src="http://226617.cn/wp-content/uploads/2009/04/3g-1-172x300.jpg" alt="image" title="Click to enlarge" /></a>      <a href="http://226617.cn/wp-content/uploads/2009/04/3g-2.jpg" onclick="return hs.expand(this);" class="highslide-image"><img src="http://226617.cn/wp-content/uploads/2009/04/3g-2-172x300.jpg" alt="image" title="Click to enlarge" /></a><br />
选择本地服务器测试了下载和上传速度，用的ftp单线程，下载峰值200kb出头，平均在100kb上下，上传峰值80多kb，平均在50kb上线。上传和下载基本处于上下波动状态忽高忽低，没有一刻是稳定的。下载的同时上传会对下载速度有一些影响。</p>
<p>浏览网页，qq等操作那是和adsl基本无异，速度飞快，比以前1x快不知道多少倍。</p>
<p>试用感觉良好，连接目前看来很稳定，可以考虑作为宽带替代方案，就是不知道费用如何。</p>
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		</item>
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		<title>iptables在防火墙应用方面的简单教程(第2版)</title>
		<link>http://226617.cn/archives/563.htm</link>
		<comments>http://226617.cn/archives/563.htm#comments</comments>
		<pubDate>Mon, 13 Apr 2009 15:48:24 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[linux相关]]></category>
		<category><![CDATA[iptables]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=563</guid>
		<description><![CDATA[#首先全部允许数据包通过，防止默认丢包的话下面删除规则造成数据包全部丢掉 #允许所有进来的包 iptables -P INPUT ACCEPT #允许所有出去的包 iptables -P OUTPUT ACCEPT #初始化iptables 清空所有规则和组 ... ]]></description>
			<content:encoded><![CDATA[<p>#首先全部允许数据包通过，防止默认丢包的话下面删除规则造成数据包全部丢掉<br />
#允许所有进来的包<br />
<span style="color: #ff0000;">iptables -P INPUT ACCEPT<br />
</span>#允许所有出去的包<br />
<span style="color: #ff0000;">iptables -P OUTPUT ACCEPT</span></p>
<p>#初始化iptables 清空所有规则和组<br />
#删除所有规则<br />
<span style="color: #ff0000;">iptables -F<br />
</span>#删除所有组<br />
<span style="color: #ff0000;">iptables -X</span></p>
<p>#这里才是正式开始配置iptables<br />
#创建新的定义firewall_in<br />
<span style="color: #ff0000;">iptables -N firewall_in</span></p>
<p>#指定firewall_in组应用到INPUT chain，类似于应用组<br />
<span style="color: #ff0000;">iptables -A INPUT -j firewall_in</span></p>
<p>#指定firewall_in组应用到FORWARD chain，类似于应用组。<br />
<span style="color: #ff0000;">iptables -A FORWARD -j firewall_in</span></p>
<p>#这里开始增加规则，这里例子里规则都是添加到firewall_in组<br />
#localhost数据包全部允许通过<br />
<span style="color: #ff0000;">iptables -A firewall_in -i lo -j ACCEPT</span></p>
<p>#所有已经建立连接的数据包全部通过<br />
<span style="color: #ff0000;">iptables -A firewall_in -m state &#8211;state RELATED,ESTABLISHED -j ACCEPT</span></p>
<p>#所有地址开放tcp 80端口<br />
<span style="color: #ff0000;">iptables -A firewall_in -p tcp -m tcp &#8211;dport 80 -j ACCEPT</span></p>
<p>#ping数据包允许每秒通过1个<br />
<span style="color: #ff0000;">iptables -A firewall_in -p icmp -m limit &#8211;limit 1/s &#8211;limit-burst 10 -j ACCEPT</span></p>
<p>#向10.1.1.0/255.255.255.0网段开放eth0网卡上面并且目的ip地址为10.1.1.1的22端口（这是一个功能示例：网卡、协议类型、源地址组、目的地址、目的端口都有体现）<br />
<span style="color: #ff0000;">iptables -A firewall_in -i eth0 -p tcp -m tcp -s 10.1.1.0/255.255.255.0 -d 10.1.1.1 –dport 22 -j ACCEPT</span></p>
<p>#下面这2行是ftp server的pasv模式开放示例，因为ftp的pasv模式端口是随机打开的所以需要另外设置ftp server的pasv端口范围为60000-60004<br />
<span style="color: #ff0000;">iptables -A firewall_in -p tcp -m tcp -s 10.1.1.2 &#8211;dport 21 -j ACCEPT<br />
iptables -A firewall_in -p tcp -m tcp -s 10.1.1.2 &#8211;dport 60000:60004 -j ACCEPT</span></p>
<p>#丢弃不符合规则的其它tcp和udp数据包，如果处于调试的最好先不要用这2行，万一规则错了就麻烦了<br />
<span style="color: #ff0000;">iptables -A firewall_in -p tcp -m tcp -j DROP<br />
iptables -A firewall_in -p udp -m udp -j DROP</span></p>
<p>#清除规则匹配数据包计数信息<br />
<span style="color: #ff0000;">iptables -Z</span></p>
<p>#禁止所有进来的包，iptables是从上往下匹配的，如果有符合的话就结束匹配了，这里丢弃和上面规则里面的丢弃相比更加彻底。<br />
#同样如果处于调试的最好先不要用这2行，万一规则错了就麻烦了<br />
<span style="color: #ff0000;">iptables -P INPUT DROP</span></p>
<p>#应许所有出去的包，这个防火墙只是简单的进行入站包的过滤，如果需要出站包也要过滤话可以给OUTPUT chain单独一个组然后把参考上面把出站规则写到对应的组里<br />
<span style="color: #ff0000;">iptables -P OUTPUT ACCEPT</span></p>
<p>#最后保存iptables，这样重启后也能应用<br />
<span style="color: #ff0000;">/etc/init.d/iptables save</span></p>
<p>虽然iptables可以通过命令进行修改插入和删除操作，但是这里极不推荐新手这样来修改iptables，我推荐大家是把我上面的这样的命令(去掉注释)保存下来，一方面是做好记录，另一方面在下次修改的时候可以很方便的修改文本，然后把命令全部粘贴进命令行就行。</p>
<p>另外查看目前iptables的内容指令：<br />
<span style="color: #ff0000;">iptables -L -vn</span></p>
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		<item>
		<title>Update Manager 主机扫描更新提示patch metadata for xxxx missing解决</title>
		<link>http://226617.cn/archives/555.htm</link>
		<comments>http://226617.cn/archives/555.htm#comments</comments>
		<pubDate>Fri, 10 Apr 2009 15:33:40 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[vmware相关]]></category>
		<category><![CDATA[Update Manager]]></category>
		<category><![CDATA[vmware]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=555</guid>
		<description><![CDATA[Update Manager是一款VMware VirtualCenter插件，可以对esx和vm操作系统 进行在线补丁更新。 前两天看到esx已经出3.5 u4了，所以今天抽空打算升级一下的，启用Update Manager，设置更新内容下载补丁都蛮正... ]]></description>
			<content:encoded><![CDATA[<p>Update Manager是一款VMware VirtualCenter插件，可以对esx和vm操作系统 进行在线补丁更新。</p>
<p>前两天看到esx已经出3.5 u4了，所以今天抽空打算升级一下的，启用Update Manager，设置更新内容下载补丁都蛮正常，结果在对esx主机进行 scan for updates（扫描更新） 的时候出错。事件里面提示patch metadata for xxxx missing. please download updates metadata first.</p>
<p>去官网kb补习了一下，说这种情况一般是esx无法连上vc的um造成的。常见的可能性就是：<br />
1是esx的防火墙没开8080的out规则<br />
2是vc的机器上可能有多个ip或者网卡，恰好um给esx的ip或者vc的hostname esx连接不上。</p>
<p>所以解决方法首先就是打开esx 防火墙的访问外部8080端口<br />
用ssh登入上esx（注意root用户默认是无法ssh登陆的）先su到root权限执行下面指令：<br />
/usr/sbin/esxcfg-firewall -o 8080,tcp,out,updatemanager</p>
<p>如果安装vc的时候选择的http端口不是8080请做相应修改。</p>
<p>然后在vc主机上在服务里停掉VMware Update Manager Service，在进入Update Manager目录修改文件：<br />
C:\Program Files\VMware\Infrastructure\Update Manager\vci-integrity.xml</p>
<p>找到<br />
&lt;HostConfig&gt;<br />
下面的<br />
&lt;PatchDepotUrl/&gt;<br />
改为<br />
&lt;PatchDepotUrl&gt;http://192.168.0.1:8080/vci/hostupdates/hostupdate&lt;/PatchDepotUrl&gt;</p>
<p>其中192.168.0.1就是esx能ping通并且访问到的vc的ip地址，8080端口为安装vc的时候选择的http端口。</p>
<p>然后再启动VMware Update Manager Service，这时应该需要在vc里面重新启用下Update Manager。然后再对esx主机进行扫描更新就可以通过了。</p>
<p>官方对于这个问题的kb：</p>
<p>http://kb.vmware.com/kb/1004914</p>
<p>http://kb.vmware.com/kb/1004330</p>
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		</item>
		<item>
		<title>mysql 5.0的mysqldump导入导出</title>
		<link>http://226617.cn/archives/552.htm</link>
		<comments>http://226617.cn/archives/552.htm#comments</comments>
		<pubDate>Wed, 08 Apr 2009 02:36:14 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[mysql相关]]></category>
		<category><![CDATA[mysql]]></category>
		<category><![CDATA[mysqldump]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=552</guid>
		<description><![CDATA[以前写过个4.0的，现在机器上都是5.0的了，也不知道兼容不兼容4.0的参数，所以干脆看着help重新写了个 我这的环境都是gbk所以下面是以gbk为例子 导出： 1 mysqldump --user=&#34;xxx&#34; --password=&#34;xxx... ]]></description>
			<content:encoded><![CDATA[<p>以前写过个4.0的，现在机器上都是5.0的了，也不知道兼容不兼容4.0的参数，所以干脆看着help重新写了个</p>
<p>我这的环境都是gbk所以下面是以gbk为例子<br />
导出：</p>

<div class="wp_syntax"><table><tr><td class="line_numbers"><pre>1
</pre></td><td class="code"><pre class="cmd" style="font-family:monospace;">mysqldump --user=&quot;xxx&quot; --password=&quot;xxx&quot; --force --quick --skip-opt --create-options --add-drop-table --default-character-set=gbk db1 &gt;db1.sql</pre></td></tr></table></div>

<p>其中&#8211;force 代表忽略错误，如果导出的数据要导入mysql 4.0的话加个参数&#8211;compatible=mysql40</p>
<p>导入：</p>

<div class="wp_syntax"><table><tr><td class="line_numbers"><pre>1
</pre></td><td class="code"><pre class="cmd" style="font-family:monospace;">mysql -u&quot;xxx&quot; -p&quot;xxx&quot; --default-character-set=gbk db1 &lt;db1.sql</pre></td></tr></table></div>

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		<item>
		<title>display_errors设置无效永远off故障一例</title>
		<link>http://226617.cn/archives/550.htm</link>
		<comments>http://226617.cn/archives/550.htm#comments</comments>
		<pubDate>Tue, 07 Apr 2009 14:23:19 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[php相关]]></category>
		<category><![CDATA[php]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=550</guid>
		<description><![CDATA[就我这台跑博客的机器，nginx-0.7.37 + php 5.2.8(fastcgi)出现个极度诡异的现象，就是无论php.ini怎么设置display_errors，永远无错误信息显示，觉得不是我搞错文件或者其它问题，别的配置都有效，就... ]]></description>
			<content:encoded><![CDATA[<p>就我这台跑博客的机器，nginx-0.7.37 + php 5.2.8(fastcgi)出现个极度诡异的现象，就是无论php.ini怎么设置display_errors，永远无错误信息显示，觉得不是我搞错文件或者其它问题，别的配置都有效，就是display_errors 设置为on 进phpinfo一看还是off，昏倒，怎么最近老是碰到问题撒，只能log到文件看出错信息。同样的环境在另外一台机器确实好的<br />
最后检查来检查去发现php-fpm.conf里面还有个关于display_errors的设置改成<value name="display_errors">1</value>就搞定了</p>
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		</item>
		<item>
		<title>一次netapp2050机头故障的修复经历</title>
		<link>http://226617.cn/archives/548.htm</link>
		<comments>http://226617.cn/archives/548.htm#comments</comments>
		<pubDate>Fri, 03 Apr 2009 11:41:20 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[硬件相关]]></category>
		<category><![CDATA[netapp]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=548</guid>
		<description><![CDATA[今天吃饭前，上网管机，惊现存储监控的页面上面闪红灯，紧急赶往机房一看，一台netapp2050的机头a处于关机状态，于是连机头b查看，机头b的cf status状态是FAS2050B has taken over FAS2050A. 目前存储处... ]]></description>
			<content:encoded><![CDATA[<p>今天吃饭前，上网管机，惊现存储监控的页面上面闪红灯，紧急赶往机房一看，一台netapp2050的机头a处于关机状态，于是连机头b查看，机头b的cf status状态是FAS2050B has taken over FAS2050A. 目前存储处于机头b接管状态。</p>
<p>于是又输了几条命令查看了下机头b的状态，当输入stats show 之后，没有出现命令行，ctrl+c也无法退出到命令行，断开终端重连输入用户名和密码后还是处于无命令行状态，顿时抓狂。</p>
<p>联系了下售后，决定先找机头a当机原因，起出机头a，由于机头a处于Waiting for giveback状态（ctrl+c重启后autoboot还是这样），无命令行，web也无法进去，直接用nfs连也无法通过。</p>
<p>到此为止，基本情况就是这样，机头a处于Waiting for giveback等待状态，需要机头b进行giveback才能回到正常工作状态，但是进行这个操作必须在机头b进行命令操作，但是机头b无论串口还是telnet都无法出现命令行。<br />
 <img src='http://226617.cn/wp-includes/images/smilies/icon_confused.gif' alt=':???:' class='wp-smiley' /><br />
抓狂了一阵后，忽然想到rsh可以直接写命令进去，试了下<br />
rsh 10.10.1.1 -l root:root rdfile /etc/log/messages</p>
<p>果然有戏，把机头a的日志给读了出来了，一看原来nvram的电池检测到问题，自动关机了<br />
Thu Apr 2 20:00:27 CST [FAS2050A: kern.shutdown:notice]: System shut down because : &#8220;NVRAM BATTERY FAILURE&#8221;.</p>
<p>把日志发给售后，netapp那边一开始说发配件换电池把，后来又打电话说无法判断是电池还是充电模块问题，干脆换机头把。 <img src='http://226617.cn/wp-includes/images/smilies/icon_eek.gif' alt=':shock:' class='wp-smiley' />  &#8230;说等会给我确定送货时间，我一琢磨下一工作日岂不是要4天后才能搞定了 <img src='http://226617.cn/wp-includes/images/smilies/icon_evil.gif' alt=':evil:' class='wp-smiley' />  。<br />
等了一会，售后又打电话过来说netapp那边分析下来应该属于固件版本太低的问题，这个版本固件可能有点bug，电池是应该好的，让我直接giveback。 <img src='http://226617.cn/wp-includes/images/smilies/icon_confused.gif' alt=':???:' class='wp-smiley' /> </p>
<p>没办法客服的话总是要听的，rsh 10.10.1.2 -l root:root cf giveback 结果提示<br />
Partner not waiting for giveback, giveback cancelled.<br />
To do a giveback without checking for partner readiness, please either set optio<br />
n &#8220;cf.giveback.check.partner&#8221; to &#8220;off&#8221; before doing &#8220;cf giveback&#8221; again, or do &#8221;<br />
cf giveback -f&#8221;.</p>
<p>The first choice disables checking for all future &#8220;cf giveback&#8221;, until it&#8217;s turn<br />
ed back to &#8220;on&#8221;. The second choice is good for this giveback only.</p>
<p>客服说我插拔过机头用cf giveback -f，咱照做，果然有反应了<br />
在机头b上面cf status，目前状态是<br />
FAS2050B has taken over FAS2050A, giveback in progress.<br />
giveback is in module &#8220;snapmirror&#8221;, 118 of 131 modules.</p>
<p>一阵等待后，提示ready for giveback，终于真不容易。。。。<br />
继续 cf giveback<br />
哗啦啦一堆信息滚过之后终于<br />
Cluster enabled，2个机头都up了</p>
<p>最后按照客服提示options autosupport.doit 2000669538 导出一份autosupport报告发了过去。<br />
客服说下周安排过来升级固件。</p>
<p>流水账就此结束，幸亏发现的及时，没有造成什么后果，这次经历之后我乖乖的还是把autosupport邮件名单添加了一份我的手机邮地址，可怜每个星期天半夜要被骚扰一次了。</p>
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		<item>
		<title>linux时间永远快8小时的问题解决</title>
		<link>http://226617.cn/archives/546.htm</link>
		<comments>http://226617.cn/archives/546.htm#comments</comments>
		<pubDate>Thu, 02 Apr 2009 15:44:56 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[linux相关]]></category>
		<category><![CDATA[linux]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=546</guid>
		<description><![CDATA[今天在给一朋友搞个环境，发现系统时间永远比现在时间快8小时 date 输出 后面是GMT+8。不知道装系统的时候怎么选的 /usr/sbin/ntpdate time.nist.gov 结果无用，tzselect重新选择Asia/Shanghai也没用。 cat ... ]]></description>
			<content:encoded><![CDATA[<p>今天在给一朋友搞个环境，发现系统时间永远比现在时间快8小时<br />
date 输出 后面是GMT+8。不知道装系统的时候怎么选的<br />
/usr/sbin/ntpdate time.nist.gov 结果无用，tzselect重新选择Asia/Shanghai也没用。<br />
cat 了一下/etc/sysconfig/clock发现ZONE还是GMT+8，手工改成Asia/Shanghai结果还是没用 <img src='http://226617.cn/wp-includes/images/smilies/icon_twisted.gif' alt=':twisted:' class='wp-smiley' /><br />
最后cat了下/etc/localtime 发现有点猫腻<br />
cp /usr/share/zoneinfo/Asia/Shanghai /etc/localtime 了一下终于搞定，真是个奇怪的毛病</p>
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		<title>高并发网络负载linux的内核优化</title>
		<link>http://226617.cn/archives/539.htm</link>
		<comments>http://226617.cn/archives/539.htm#comments</comments>
		<pubDate>Thu, 02 Apr 2009 08:23:30 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[linux相关]]></category>
		<category><![CDATA[linux]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=539</guid>
		<description><![CDATA[近期在上squid，由于访问量集中在一台主机上，虽然经过了一些优化但是还是大量存在timewait的链接。打算在细挖下内核的一些网络参数的优化。目前还在调整中，如果照着修改的话先cat 备份下... ]]></description>
			<content:encoded><![CDATA[<p>近期在上squid，由于访问量集中在一台主机上，虽然经过了一些优化但是还是大量存在timewait的链接。打算在细挖下内核的一些网络参数的优化。目前还在调整中，如果照着修改的话先cat 备份下你系统现在的值<br />
1.可以改变滑动窗口的大小 (默认应该就是“1”)<br />
echo &#8220;1&#8243; &gt; /proc/sys/net/ipv4/tcp_window_scaling</p>
<p>2.修改内核共享内存限制 (新的系统应该默认就是这值)<br />
echo 4294967296 &gt;/proc/sys/kernel/shmall<br />
echo 68719476736 &gt;/proc/sys/kernel/shmmax</p>
<p>3.可使用的代理端口<br />
echo &#8220;1024 65000&#8243; &gt; /proc/sys/net/ipv4/ip_local_port_range</p>
<p>4.禁止广播和ping入<br />
echo &#8220;1&#8243; &gt; /proc/sys/net/ipv4/icmp_echo_ignore_broadcasts<br />
echo &#8220;1&#8243; &gt; /proc/sys/net/ipv4/icmp_ignore_bogus_error_responses</p>
<p>5./proc/sys/net/ipv4/netfilter/ip_conntrack_max 改大到 268435456 默认只有65536 (这个就是连接跟踪表，一味的改大反而会增加系统的负载，一般来讲默认值也够，正确的优化方向是加快连接的关闭释放资源，我这只是在优化初期临时改大。注意/proc/sys/net/ipv4/ip_conntrack_max的值要大于这个值)</p>
<p>6.echo &#8220;1800&#8243; &gt; /proc/sys/net/ipv4/netfilter/ip_conntrack_tcp_timeout_established<br />
默认确立连接会在5天后失效，改为半小时后失效，减少ip_conntrack的有效连接数量。</p>
<p>7.echo 1 &gt; /proc/sys/net/ipv4/tcp_syncookies<br />
防范SYN DDOS攻击，打开TCPsyncookies,CENTOS4以上的内核是支持的。</p>
<p>8.echo 2048 &gt; /proc/sys/net/ipv4/tcp_max_syn_backlog<br />
SYN列队长度，不要设置太高，会消耗相应的内存。</p>
<p>9.echo 3 &gt; /proc/sys/net/ipv4/tcp_synack_retries<br />
SYN重试次数。</p>
<p>10.echo 3 &gt; /proc/sys/net/ipv4/tcp_syn_retries<br />
SYN重试次数。</p>
<p>还有一些没深入研究的<br />
echo 600 &gt; /proc/sys/net/ipv4/netfilter/ip_conntrack_generic_timeout<br />
echo 10 &gt; /proc/sys/net/ipv4/netfilter/ip_conntrack_tcp_timeout_close<br />
echo 120 &gt; /proc/sys/net/ipv4/netfilter/ip_conntrack_tcp_timeout_close_wait<br />
echo 120 &gt; /proc/sys/net/ipv4/netfilter/ip_conntrack_tcp_timeout_fin_wait<br />
echo 60 &gt; /proc/sys/net/ipv4/netfilter/ip_conntrack_tcp_timeout_time_wait<br />
echo 30 &gt; /proc/sys/net/ipv4/netfilter/ip_conntrack_udp_timeout</p>
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		</item>
		<item>
		<title>IE8下utf8页面调用JavaScript的编码bug</title>
		<link>http://226617.cn/archives/534.htm</link>
		<comments>http://226617.cn/archives/534.htm#comments</comments>
		<pubDate>Thu, 02 Apr 2009 02:42:43 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[软件相关]]></category>
		<category><![CDATA[ie8]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=534</guid>
		<description><![CDATA[情况是这样的，在升级ie8之后查看网页发现有2块乱码，看了看源代码，发现是调用的JavaScript &#60;script language=&#8221;javascript&#8221; type=&#8221;text/javascript&#8221; src=&#8221;http://www.abc.com/api/javascript.php?k... ]]></description>
			<content:encoded><![CDATA[<p>情况是这样的，在升级ie8之后查看网页发现有2块乱码，看了看源代码，发现是调用的JavaScript</p>
<p>&lt;script language=&#8221;javascript&#8221; type=&#8221;text/javascript&#8221; src=&#8221;http://www.abc.com/api/javascript.php?key=bbs_jinpai&#8221; charset=&#8221;utf-8&#8243;&gt;&lt;/script&gt;</p>
<p>2个乱码区块都是以charset=&#8221;utf-8&#8243;方式调用的，查看了数据源，又发现这2个区块原本都是gb2312编码然后iconv转换到utf8的，于是改为不转换，仍然以gb2312输出，然后ie8以charset=&#8221;utf-8&#8243;方式调用竟然显示正常，不过其它浏览器就乱码了。最终跳过iconv以gb2312输出然后用charset=&#8221;gb2312&#8243;调用都正常了。</p>
<p>总结：如果输出是gb2312然后转换成utf8方式的js，在ie8下面以charset=&#8221;utf-8&#8243;调用是乱码，只有原生输出是utf8的才正常。应该是个bug</p>
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		<title>Mysql Innodb 引擎优化</title>
		<link>http://226617.cn/archives/526.htm</link>
		<comments>http://226617.cn/archives/526.htm#comments</comments>
		<pubDate>Tue, 31 Mar 2009 14:12:27 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[mysql相关]]></category>
		<category><![CDATA[innodb]]></category>
		<category><![CDATA[mysql]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=526</guid>
		<description><![CDATA[参数篇 作/译者：吴炳锡，来源：http://imysql.cn　＆　http://imysql.cn/blog/3208　转载请注明作/译者和出处，并且不能用于商业用途，违者必究。 介绍： 　　InnoDB给MySQL提供了具有提交，回滚和崩溃... ]]></description>
			<content:encoded><![CDATA[<p>参数篇</p>
<p>作/译者：吴炳锡，来源：http://imysql.cn　＆　http://imysql.cn/blog/3208　转载请注明作/译者和出处，并且不能用于商业用途，违者必究。</p>
<p>介绍：<br />
　　InnoDB给MySQL提供了具有提交，回滚和崩溃恢复能力的事务安全（ACID兼容）存储引擎。InnoDB锁定在行级并且也在SELECT语句提供一个Oracle风格一致的非锁定读。这些特色增加了多用户部署和性能。没有在InnoDB中扩大锁定的需要，因为在InnoDB中行级锁定适合非常小的空间。InnoDB也支持FOREIGN KEY强制。在SQL查询中，你可以自由地将InnoDB类型的表与其它MySQL的表的类型混合起来，甚至在同一个查询中也可以混合。<br />
　Innodb 的创始人：Heikki Tuuri<br />
　Heikki Tuuri在Ｉｎｎｏｄｂ的Ｂｕｇ社区里也是很活跃的，如果遇到Ｂｕｇ也可以直接提到社区，得到作者的解答。</p>
<p>为什么要学习Ｉｎｎｏｄｂ的调优：<br />
　　目前来说：InnoDB是为Mysql处理巨大数据量时的最大性能设计。它的CPU效率可能是任何其它基于磁盘的关系数据库引擎所不能匹敌的。在数据量大的网站或是应用中Innodb是倍受青睐的。<br />
　　另一方面，在数据库的复制操作中Innodb也是能保证master和slave数据一致有一定的作用。</p>
<p>参数调优内容：<br />
　　1. 内存利用方面<br />
　　2. 日值控制方面<br />
　　3.　文件IO分配，空间占用方面<br />
　　4. 其它相关参数</p>
<p>１.内存利用方面：<br />
首先介绍一个Innodb最重要的参数：<br />
innodb_buffer_pool_size<br />
　　这个参数和MyISAM的key_buffer_size有相似之处，但也是有差别的。这个参数主要缓存innodb表的索引，数据，插入数据时的缓冲。为Innodb加速优化首要参数。<br />
　　该参数分配内存的原则：这个参数默认分配只有8M，可以说是非常小的一个值。如果是一个专用ＤＢ服务器，那么他可以占到内存的70%-80%。这个参数不能动态更改，所以分配需多考虑。分配过大，会使Swap占用过多，致使Mysql的查询特慢。如果你的数据比较小，那么可分配是你的数据大小＋１０％左右做为这个参数的值。例如：数据大小为５０Ｍ,那么给这个值分配innodb_buffer_pool_size＝６４Ｍ<br />
设置方法：<br />
innodb_buffer_pool_size=4G<br />
这个参数分配值的使用情况可以根据show innodb status\G;中的<br />
&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;-<br />
BUFFER POOL AND MEMORY<br />
&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;-<br />
Total memory allocated 4668764894;<br />
去确认使用情况。</p>
<p>第二个：<br />
innodb_additional_mem_pool：<br />
作用：用来存放Innodb的内部目录<br />
这个值不用分配太大，系统可以自动调。不用设置太高。通常比较大数据设置16Ｍ够用了，如果表比较多，可以适当的增大。如果这个值自动增加，会在error log有中显示的。<br />
分配原则：<br />
用show innodb status\G;去查看运行中的ＤＢ是什么状态（参考BUFFER POOL AND MEMORY段中），然后可以调整到适当的值。<br />
&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;-<br />
BUFFER POOL AND MEMORY<br />
&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;-<br />
Total memory allocated 4668764894; in additional pool allocated 16777216<br />
参考：in additional pool allocated 16777216<br />
根据你的参数情况，可以适当的调整。<br />
设置方法：<br />
innodb_additional_mem_pool=16M</p>
<p>２.关于日值方面：<br />
innodb_log_file_size<br />
作用：指定日值的大小<br />
分配原则：几个日值成员大小加起来差不多和你的innodb_buffer_pool_size相等。上限为每个日值上限大小为4G.一般控制在几个ＬＯＧ文件相加大小在２Ｇ以内为佳。具体情况还需要看你的事务大小，数据大小为依据。<br />
说明：这个值分配的大小和数据库的写入速度，事务大小，异常重启后的恢复有很大的关系。<br />
设置方法：<br />
innodb_log_file_size=256M</p>
<p>innodb_log_files_in_group<br />
作用：指定你有几个日值组。<br />
分配原则：　一般我们可以用２－３个日值组。默认为两个。<br />
设置方法：<br />
innodb_log_files_in_group=3</p>
<p>innodb_log_buffer_size：<br />
作用：事务在内存中的缓冲。<br />
分配原则：控制在2-8M.这个值不用太多的。他里面的内存一般一秒钟写到磁盘一次。具体写入方式和你的事务提交方式有关。在Ｏｒａｃｌｅ等数据库了解这个，一般最大指定为３Ｍ比较合适。<br />
参考：Innodb_os_log_written(show global status 可以拿到)<br />
如果这个值增长过快，可以适当的增加innodb_log_buffer_size<br />
另外如果你需要处理大理的ＴＥＸＴ，或是ＢＬＯＢ字段，可以考虑增加这个参数的值。<br />
设置方法：<br />
innodb_log_buffer_size=3M</p>
<p>innodb_flush_logs_at_trx_commit<br />
作用：控制事务的提交方式<br />
分配原则：这个参数只有３个值，０，１，２请确认一下自已能接受的级别。默认为１，主库请不要更改了。<br />
性能更高的可以设置为０或是２，但会丢失一秒钟的事务。<br />
说明：<br />
这个参数的设置对Ｉｎｎｏｄｂ的性能有很大的影响，所以在这里给多说明一下。<br />
当这个值为1时：innodb 的事务LOG在每次提交后写入日值文件，并对日值做刷新到磁盘。这个可以做到不丢任何一个事务。<br />
当这个值为2时：在每个提交，日志缓冲被写到文件，但不对日志文件做到磁盘操作的刷新,在对日志文件的刷新在值为2的情况也每秒发生一次。但需要注意的是，由于进程调用方面的问题，并不能保证每秒１００％的发生。从而在性能上是最快的。但操作系统崩溃或掉电才会删除最后一秒的事务。<br />
当这个值为0时：日志缓冲每秒一次地被写到日志文件，并且对日志文件做到磁盘操作的刷新，但是在一个事务提交不做任何操作。mysqld进程的崩溃会删除崩溃前最后一秒的事务。</p>
<p>从以上分析，当这个值不为１时，可以取得较好的性能，但遇到异常会有损失，所以需要根据自已的情况去衡量。</p>
<p>设置方法：<br />
innodb_flush_logs_at_trx_commit=1</p>
<p>3.　文件IO分配，空间占用方面<br />
innodb_file_per_table<br />
作用：使每个Innodb的表，有自已独立的表空间。如删除文件后可以回收那部分空间。<br />
分配原则：只有使用不使用。但ＤＢ还需要有一个公共的表空间。<br />
设置方法：<br />
innodb_file_per_table=1</p>
<p>innodb_file_io_threads<br />
作用：文件读写ＩＯ数，这个参数只在Windows上起作用。在LINUX上只会等于４<br />
设置方法：<br />
innodb_file_io_threads=4</p>
<p>innodb_open_files<br />
作用：限制Innodb能打开的表的数据。<br />
分配原则：如果库里的表特别多的情况，请增加这个。这个值默认是３００。<br />
设置方法：<br />
innodb_open_files=800<br />
请适当的增加table_cache</p>
<p>4. 其它相关参数<br />
这里说明一个比较重要的参数：<br />
innodb_flush_method<br />
作用：Ｉｎｎｏｄｂ和系统打交道的一个ＩＯ模型<br />
分配原则：Windows不用设置。<br />
Ｕｎｉｘ可以设置：fsync() or O_SYNC/O_DSYNC<br />
如果系统可以禁止系统的Ｃａｃｈｅ那就把他禁了。<br />
Ｌｉｎｕｘ可以选择：O_DIRECT<br />
直接写入磁盘，禁止系统Ｃａｃｈｅ了<br />
设置方法：<br />
innodb_flush_method=O_DIRECT</p>
<p>innodb_max_dirty_pages_pct<br />
作用：控制Innodb的脏页在缓冲中在那个百分比之下，值在范围1-100,默认为90.<br />
这个参数的另一个用处：当Ｉｎｎｏｄｂ的内存分配过大，致使Ｓｗａｐ占用严重时，可以适当的减小调整这个值，使达到Ｓｗａｐ空间释放出来。建义：这个值最大在９０％，最小在１５％。太大，缓存中每次更新需要致换数据页太多，太小，放的数据页太小，更新操作太慢。<br />
设置方法：<br />
innodb_max_dirty_pages_pct＝90<br />
动态更改需要有Ｓｕｐｅｒ权限：<br />
set global innodb_max_dirty_pages_pct=50;</p>
<p>总结：<br />
　　这里只算是列出了Ｉｎｎｏｄｂ部分的重要参数，不能认为是对Ｍｙｓｑｌ的整体调优。Ｍｙｓｑｌ的参数一般分为：全局参数，具体引擎的参数。全局参数方面请参考http://imysql.cn/2007_12_08_optimize_mysql_under_linux yejr的那个Ｍｙｓｑｌ调优的ＰＰＴ。</p>
]]></content:encoded>
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		</item>
		<item>
		<title>linux下文件批量改名的一些方法</title>
		<link>http://226617.cn/archives/519.htm</link>
		<comments>http://226617.cn/archives/519.htm#comments</comments>
		<pubDate>Mon, 30 Mar 2009 07:22:22 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[linux相关]]></category>
		<category><![CDATA[linux]]></category>
		<category><![CDATA[改名]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=519</guid>
		<description><![CDATA[A 加后缀 1.问题：同以目录下有海量以日期命名的文件，其中有的有后缀，有的以点结尾，如20020101.，20020102.，……，20020101.td，20020102.td…… 要求： 把所有以点结尾的加上后缀.ts 我的方法： #... ]]></description>
			<content:encoded><![CDATA[<p>A 加后缀</p>
<p>1.问题：同以目录下有海量以日期命名的文件，其中有的有后缀，有的以点结尾，如20020101.，20020102.，……，20020101.td，20020102.td……<br />
要求： 把所有以点结尾的加上后缀.ts<br />
我的方法：<br />
  #！/bin/bash<br />
  for files in `ls *.`<br />
  do<br />
        mv $files `echo &#8220;$filests&#8221; `<br />
  done</p>
<p>2. 同上</p>
<p>     mv  $files ${files}ts</p>
<p>3. 同上</p>
<p>     mv  $files  `$files.ts|sed &#8216;s/\.//&#8217; `</p>
<p>4. file ＝>file.txt</p>
<p>       mv  $files  $files.txt</p>
<p>5. *.04  => *04.txt</p>
<p>    mv $files $(echo ${files}.txt|sed &#8216;s/\.//1&#8242;)</p>
<p>    或者</p>
<p>   mv $files  `echo ${files}.txt|sed &#8216;s/\.//1&#8242; `</p>
<p>B 改后缀(.old => .new)</p>
<p>1. rename</p>
<p>     rename .old .new  *</p>
<p>2.<br />
    mv $files ${file%.old}.new</p>
<p>3.<br />
    mv $files `echo $files|tr .old .new`</p>
<p>4.<br />
    mv $files `echo $files|sed &#8216;s/\.old/\.new/&#8217; `</p>
<p>C 去后缀 （*.dat ＝> *)</p>
<p>1.  mv $files `echo $files |sed &#8216;s/\.dat//&#8217; `</p>
<p>2.  mv $files  `echo $files|tr .dat  （4空格）`</p>
<p>D 改前缀 (re* => un*)</p>
<p>1.  mv $files un${$files#re}</p>
<p>2.  mv $files `echo $files | tr re un`</p>
]]></content:encoded>
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		</item>
		<item>
		<title>PHP.ini配置文件中文</title>
		<link>http://226617.cn/archives/489.htm</link>
		<comments>http://226617.cn/archives/489.htm#comments</comments>
		<pubDate>Fri, 27 Mar 2009 15:00:19 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[php相关]]></category>
		<category><![CDATA[php]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=489</guid>
		<description><![CDATA[;;;;;;;;;;; ; 警告 ; ;;;;;;;;;;; ; 此配置文件是对于新安装的PHP的默认设置. ; 默认情况下,PHP使用此配置文件安装 ; 此配置针对开发目的,并且*不是*针对生产环境 ; 基于一些安全方面的考虑,在你的网... ]]></description>
			<content:encoded><![CDATA[<p>;;;;;;;;;;;<br />
; 警告 ;<br />
;;;;;;;;;;;<br />
; 此配置文件是对于新安装的PHP的默认设置.<br />
; 默认情况下,PHP使用此配置文件安装<br />
; 此配置针对开发目的,并且*不是*针对生产环境<br />
; 基于一些安全方面的考虑,在你的网站上线之前,请考虑使用php.ini-recommended<br />
; 以及在线文档 <a href="http://php.net/manual/en/security.php">http://php.net/manual/en/security.php</a>.<br />
;;;;;;;;;;;;;;;;;;;<br />
; 关于 php.ini   ;<br />
;;;;;;;;;;;;;;;;;;;<br />
; 此文件控制了PHP行为的很多方面.  为了让PHP能够读取它<br />
; 必须命名为 &#8216;php.ini&#8217;.  PHP 在其当前工作目录,由PHPRC环境变量指定目录<br />
; 以及由编译时指定的目录(按此顺序)查找此文件<br />
; 在Windows环境下, 编译时目录是Windows目录.<br />
; 在命令行模式下查找php.ini的目录可以被-c参数覆盖.<br />
;<br />
; 此文件的语法非常简单.<br />
; 空行和由分号开始的行会被忽略(你可能已经猜到了).<br />
; 段的开头(例如 [Foo]) 同样会被悄悄忽略<br />
; 即使在将来他们可能会有其他作用.<br />
;<br />
; 使用以下语法来设定指令:<br />
; directive = value<br />
; 指令 = 值<br />
; 指令名称是 *大小写敏感* &#8211; foo=bar 和 FOO=bar 是不同的.<br />
;<br />
; 值可以是字符串,数值,PHP常量 (例如 E_ALL 和 M_PI),<br />
; INI 常量 (On, Off, True, False, Yes, No 和 None) 或者一个表达式<br />
; (例如 E_ALL &amp; ~E_NOTICE), 或者带引号的字串 (&#8220;foo&#8221;).<br />
;<br />
; 在INI文件中的表达式只能使用逻辑运算和圆括号:<br />
; |        逻辑或<br />
; &amp;       逻辑与<br />
; ~       逻辑非<br />
; !        取反<br />
;<br />
; 逻辑标志可以使用1,On,True或者Yes来打开.<br />
; 也可以使用0, Off, False 或者 No来关闭.<br />
;<br />
; 在等号后面不写任何内容代表了一个空字符串<br />
; 或者使用 None 关键词:<br />
;<br />
;  foo =         ; 将foo设置成一个空字串<br />
;  foo = none    ; 将foo设置成一个空字串<br />
;  foo = &#8220;none&#8221;  ; 将foo设置成字串 &#8216;none&#8217;<br />
;<br />
; 如果你在值中使用了常量, 并且这个常量属于一个动态加载的扩展模块<br />
; (不论是PHP扩展还是Zend扩展),<br />
; 那你只能在加载这些扩展 *之后* 使用这些常量.<br />
;<br />
;<br />
;;;;;;;;;;;;;;;;;;;<br />
; 关于这个文件  ;<br />
;;;;;;;;;;;;;;;;;;;<br />
; 在php.ini-dist 文件中所有的值都相当于内建的默认值<br />
; (就是如果没有使用php.ini, 或者如果你删除了这些行,<br />
; 就和内建的默认值一样).<br />
;;;;;;;;;;;;;;;;;;;;<br />
; 语言选项 ;<br />
;;;;;;;;;;;;;;;;;;;;</p>
<p>; 打开在Apache下的PHP脚本语言引擎<br />
engine = On</p>
<p>; 打开Zend Engine兼容模式(PHP 4.x)<br />
zend.ze1_compatibility_mode = Off</p>
<p>; 允许 &lt;? 标签.  否则,只有 &lt;?php 和 &lt;script&gt; 标签被认为是PHP脚本.<br />
; 注意: 尽可能避免在开发可重新发布的程序或者库的时候使用简略标签,或者在不受你控制的服务器下发布,<br />
; 因为简略标签可能不被目标服务器支持.为了可移植性, 可重新发布的代码, 请不要使用简略标签<br />
short_open_tag = On</p>
<p>; 使用ASP风格 &lt;% %&gt; 标签.<br />
asp_tags = Off</p>
<p>; 浮点数中数值的有效位数(浮点数精度).<br />
precision    =  12</p>
<p>; 强制2000年兼容 (可能引起不兼容浏览器的问题)<br />
y2k_compliance = On</p>
<p>; 输出缓冲允许在你发送了body内容之后发送header(包括 cookies)<br />
; 代价是稍稍减缓了PHP输出层<br />
; 你可以在运行时调用 output buffering 函数来打开此功能<br />
; 你也可以将此指令设置为On来对所有文件打开输出缓冲<br />
; 如果你想将这个缓冲区限制到特定大小 &#8211; 你可以使用最大的字节数来代替&#8217;On&#8217;,来作为这个指令的参数 (例如 output_buffering=4096).<br />
output_buffering = Off</p>
<p>; 你可以将所有你脚本输出的内容重定向到指定函数. <br />
; 例如, 如果你设置 output_handler 到 &#8220;mb_output_handler&#8221;,<br />
; 字符编码会被转换成为指定的编码..<br />
; 设置任何的输出处理句柄会自动打开输出缓冲.<br />
; 注意: 如果想编写可移植脚本就不要依赖此INI配置<br />
;       取而代之的是, 明确的使用 ob_start() 来设置输出处理句柄.<br />
;       使用此ini指令可能引起问题,除非你很清楚的理解脚本正在做什么.<br />
; 注意: 你不能同时使用 &#8220;mb_output_handler&#8221; 和 &#8220;ob_iconv_handler&#8221;<br />
;       并且你不能同时使用 &#8220;ob_gzhandler&#8221; 和 &#8220;zlib.output_compression&#8221;.<br />
; 注意: 如果使用zlib.output_handler指令开启zlib输出压缩, 该指令必须为空.<br />
;output_handler =</p>
<p>; 使用zlib库对输出进行压缩<br />
; 对此选项的有效值是 &#8216;off&#8217;, &#8216;on&#8217;, 或者字节数 (用来压缩的缓冲大小 , 默认是 4KB)<br />
; 注意: 结果的chunk大小可能由于压缩对象的大小而不同.<br />
;       PHP输出块的大小一般压缩之后每个大小时几百个字节.<br />
;       如果你希望藉由一个大块的堆大小来获取更好的性能, 需要额外的打开 output_buffering 选项.<br />
; 注意: 你必须使用 zlib.output_handler 来替代标准的<br />
;       output_handler, 否则输出可能会有问题.<br />
zlib.output_compression = Off<br />
;zlib.output_compression_level = -1</p>
<p>; 这里激活 zlib.output_compression 之后,你无法再指定额外的输出处理.<br />
; 这个设置和 output_handler 一样,但是处理顺序不同.<br />
;zlib.output_handler =</p>
<p>; 立即刷新告知 PHP 让输出层在每次输出块之后立刻自动刷新.<br />
; 这和每次调用print()或者echo()函数以及任何一种HTML块后调用flush()一样.<br />
; 打开此选项会严重导致性能下降,一般只有用于调试情况下才建议打开.<br />
implicit_flush = Off</p>
<p>; 如果反序列器找到一个可以作为示例的未定义类.未序列化的回调函数会被调用(使用未定义的类名作为参数),<br />
; 如果特定的函数未被定义或者如果此函数没有包含/实现丢失的类,则会发生一个警告.<br />
; 如果只有你真想要实现类似的回调函数,才设定此入口.<br />
unserialize_callback_func=</p>
<p>; 当浮点和双精度被序列化后,浮点号后由 serialize_precision 指定存储精确度的有效位数.<br />
; 默认值是当浮点数被反序列解码后,数值仍旧相同.<br />
serialize_precision = 100</p>
<p>; 是否打开强制通过引用传递参数给函数<br />
; 此方法被反对并且很有可能在未来版本的PHP/Zend中不再被支持.<br />
; 被孤立的指定的方法是参数应该在函数被声明的时候按照引用传入.<br />
; 你被鼓励来尝试上述方法并关闭此选项来确保你脚本在今后的新版本中仍旧可以正常工作 ( 每次你使用此特性的时候会受到一个警告<br />
; 并且参数会传值而不是传引用).<br />
allow_call_time_pass_reference = On</p>
<p>;<br />
; 安全模式<br />
;<br />
safe_mode = Off</p>
<p>; 默认情况下,安全模式在打开文件时,使用UID来比对检测.<br />
; 如果你只想使用GID做宽松的比对,<br />
; 打开 safe_mode_gid.<br />
safe_mode_gid = Off</p>
<p>; 当 safe_mode 被打开, 此目录下包含的文件和子文件夹的UID/GID 检测会被绕过.<br />
; (目录必须在 include_path 中存在或者必须在包含时使用全路径)<br />
safe_mode_include_dir =</p>
<p>; 当 safe_mode 被打开, 只有在 safe_mode_exec_dir 中定义的可执行文件能够通过exec函数组打开执行.<br />
safe_mode_exec_dir =</p>
<p>; 设定某些的环境变量可能成为潜在的安全隐患.<br />
; 此指令包含一个逗号分隔的前导列表.<br />
; 在安全模式中, 用户可能只能改变符合这里所给出前导字符的变量.<br />
; 默认情况下,用户只能改变以PHP_开头的变量(例如. PHP_FOO=BAR).<br />
;<br />
; 注意:  如果此指令为空, PHP会允许用户修改任何环境变量!<br />
safe_mode_allowed_env_vars = PHP_</p>
<p>; 此指令包含了一个用逗号分隔的环境变量列表, 用户无法通过 putenv() 函数来修改列表中的环境变量.<br />
; 这些变量即便已经在 safe_mode_allowed_env_vars 所设定的列表中,也会被被保护不允许修改.<br />
safe_mode_protected_env_vars = LD_LIBRARY_PATH</p>
<p>; 如果设置了open_basedir, 将会限制文件操作只能是此指令下的目录和子目录.<br />
; 此指令对于每目录或者每虚拟主机配置文件最有意义. 此指令* 不会 *受安全模式开或者关的影响.<br />
;open_basedir =</p>
<p>; 此指令允许你为了安全原因关闭指定的函数.<br />
; 它接受以逗号分隔的函数名的列表.<br />
; 此指令* 不会 *受安全模式开或者关的影响.<br />
disable_functions =</p>
<p>; 此指令允许你由于安全原因关闭指定的类.<br />
; 它接受以逗号分隔的类名的列表.<br />
; 此指令* 不会 *受安全模式开或者关的影响.<br />
disable_classes =</p>
<p>; 语法高亮模式的色彩. 任何在 &lt;span style=&#8221;color: ???????&#8221;&gt; 中可接受的值都可以使用.<br />
;highlight.string  = #DD0000<br />
;highlight.comment = #FF9900<br />
;highlight.keyword = #007700<br />
;highlight.bg      = #FFFFFF<br />
;highlight.default = #0000BB<br />
;highlight.html    = #000000</p>
<p>; 如果打开, 即便用户放弃了的请求也会被执行完成.<br />
; 在执行可能被用户打断或者浏览器超时所中断的请求时打开此选项.<br />
; ignore_user_abort = On</p>
<p>; 指定PHP使用的实际路径的缓冲. 对于PHP打开很多文件来处理很多文件操作的系统上,应该增加此值.<br />
; realpath_cache_size=16k</p>
<p>; 对于给定文件或者目录的缓冲真实路径信息的缓冲保留秒数. 对于很少修改文件的系统可以考虑增加此值.<br />
; realpath_cache_ttl=120</p>
<p>;<br />
; 其他<br />
;<br />
; 考虑到PHP可能被其所安装的服务器上暴露的事实(例如. 被web服务器作为头部信息的签名).<br />
; 任何情况下这虽然不是安全威胁, 仍有可能暴露在你的服务器上是否正在使用PHP.<br />
expose_php = On<br />
;;;;;;;;;;;;;;;;;;;<br />
; 资源限制 ;<br />
;;;;;;;;;;;;;;;;;;;</p>
<p>; 每个脚本最大执行秒数<br />
max_execution_time = 30<br />
; 每个脚本用来分析请求数据的最大时间<br />
max_input_time = 60<br />
; 最大输入变量的嵌套级别<br />
;max_input_nesting_level = 64<br />
; 每个脚本能够使用的最大内存数量 (128MB)<br />
memory_limit = 128M<br />
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;<br />
; 错误处理和记录 ;<br />
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;</p>
<p>; 错误报告时一个位. 对每一个数值取或可以得到最终的报告级别<br />
; E_ALL             &#8211; 所有错误和警告 (不包含 E_STRICT)<br />
; E_ERROR           &#8211; 致命的运行时错误<br />
; E_RECOVERABLE_ERROR  &#8211; 几乎致命的运行时错误<br />
; E_WARNING         &#8211; 运行时警告 (非致命错误)<br />
; E_PARSE           &#8211; 编译时语法错误<br />
; E_NOTICE          &#8211; 运行时提醒 (这些警告常常由你代码中的bug导致, 但是也有可能是有意的行为 (例如, 使用一个未初始化的变量并依赖于其会被自动初始化成为一个空字符串的事实)<br />
; E_STRICT          &#8211; 运行时提醒, 打开后PHP会给出针对你代码的最易移植和最好向后兼容性的建议<br />
; E_CORE_ERROR      &#8211; PHP初始化启动时的致命错误<br />
; E_CORE_WARNING    &#8211; 在PHP初始化时发生的警告 (非致命错误)<br />
; E_COMPILE_ERROR   &#8211; 致命的编译时错误<br />
; E_COMPILE_WARNING &#8211; 编译时警告 (非致命)<br />
; E_USER_ERROR      &#8211; 用户产生的错误信息<br />
; E_USER_WARNING    &#8211; 用户产生的警告信息<br />
; E_USER_NOTICE     &#8211; 用户产生的提示信息<br />
;<br />
;例子:<br />
;<br />
;   &#8211; 显示所有错误, 除了提示以及代码标准警告以外<br />
;<br />
;error_reporting = E_ALL &amp; ~E_NOTICE<br />
;<br />
;   &#8211; 显示所有错误,除了提示以外<br />
;<br />
;error_reporting = E_ALL &amp; ~E_NOTICE | E_STRICT<br />
;<br />
;   &#8211; 只显示错误<br />
;<br />
;error_reporting = E_COMPILE_ERROR|E_RECOVERABLE_ERROR|E_ERROR|E_CORE_ERROR<br />
;<br />
;   &#8211; 显示出了提示以及代码标准警告之外的错误<br />
;<br />
error_reporting  =  E_ALL &amp; ~E_NOTICE</p>
<p>; 打印输出错误 (作为输出的一部分).  对于生产环境的网站来说,<br />
; 强烈建议你关闭此选项, 使用错误日志来替代 (详情参考下面内容). <br />
; 在一个生产环境下的web站点打开display_errors可能泄漏安全信息给最终用户, 例如web服务器的文件路径,你数据库的结构或者其他信息.<br />
;<br />
; display_errors可用的值:<br />
;<br />
; Off        &#8211; 不显示任何错误信息<br />
; stderr     &#8211; 将错误信息输出到STDERR (只有 CGI/CLI 格式下有效!)<br />
;<br />
;display_errors = &#8220;stderr&#8221;<br />
;<br />
; stdout (On) &#8211; 输出错误信息到STDOUT上<br />
;<br />
display_errors = On</p>
<p>; 即使 display_errors 打开后,PHP启动序列中发生的错误也不会显示.<br />
; 强烈建议你保持 display_startup_errors 关闭状态, 除非在排错<br />
display_startup_errors = Off</p>
<p>; 将错误输入到日志文件 (服务器指定的log,stderr或者error_log (以下指定))<br />
; 和上面提到的一样, 强烈建议你在生产环境的web站点下使用错误日志来代替错误显示.<br />
log_errors = Off</p>
<p>; 设定log_errors的最大长度. 在 error_log 关于源的信息也计算在内.<br />
; 默认是1024, 设置为0可以不限制任何最大长度.<br />
log_errors_max_len = 1024</p>
<p>; 不要记录重复的信息.必须出现在同样文件的相同行之中的才被认为是重复信息,除非 ignore_repeated_source 被设为 true.<br />
ignore_repeated_errors = Off</p>
<p>; 当忽略重复消息时忽略消息的来源. 当此设置打开后,不再记录来自不同文件或者不同行的相同消息.<br />
ignore_repeated_source = Off</p>
<p>; 如果此选项被设置为 Off, 那么内存泄漏不会被显示 (不论在stdout还是在日志中).<br />
; 此项仅在debug编译模式下有效, 并且错误报告需要包含 E_WARNING<br />
report_memleaks = On</p>
<p>;report_zend_debug = 0</p>
<p>; 在$php_errormsg中保存最后一次错误/警告消息 (逻辑值).<br />
track_errors = Off</p>
<p>; 关闭在错误信息中所包含的HTML标签.<br />
; 注意: 永远不要再生产环境中使用此特性.<br />
;html_errors = Off</p>
<p>; 如果html_errors 设置为On, 则PHP产生可点击的错误信息,点击后会跳转到描述此错误或者引起此错误的函数具体信息的页面.<br />
; 你可以从 <a href="http://www.php.net/docs.php">http://www.php.net/docs.php</a> 下载一份PHP手册的副本<br />
; 并且将 docref_root指向你放置本地拷贝的以&#8217;/'开头的.<br />
; 你同时必须指定文件文件的包含点的扩展名.<br />
; 注意: 永远不要再生产环境中使用此特性.<br />
;docref_root = &#8220;/phpmanual/&#8221;<br />
;docref_ext = .html</p>
<p>; 在输出的错误信息前加上的字符串.<br />
;error_prepend_string = &#8220;&lt;font color=#ff0000&gt;&#8221;</p>
<p>; 在输出的错误信息之后加上的字符串.<br />
;error_append_string = &#8220;&lt;/font&gt;&#8221;</p>
<p>; 将错误记录到指定文件.<br />
;error_log = filename</p>
<p>; 将错误记录到 syslog (NT系统上的Event Log在Windows 95下不可用).<br />
;error_log = syslog<br />
;;;;;;;;;;;;;;;;;<br />
; 文件处理 ;<br />
;;;;;;;;;;;;;;;;;<br />
;<br />
; 注意 &#8211; track_vars 在PHP 4.0.3 中总是打开的</p>
<p>; 在PHP产生的URL中用来分隔参数的符号.<br />
; 默认是 &#8220;&amp;&#8221;.<br />
;arg_separator.output = &#8220;&amp;amp;&#8221;</p>
<p>; PHP用来将URL分割输入到变量中的分隔符.<br />
; 默认是 &#8220;&amp;&#8221;.<br />
; 注意: 所有包含在指令内的字符都会被认为是分隔符!<br />
;arg_separator.input = &#8220;;&amp;&#8221;</p>
<p>; 此指令描述了PHP注册GET, POST, Cookie, 环境 和 内置变量的顺序  (各自使用G, P, C, E 和 S , 一般使用 EGPCS 或 GPC).  注册使用从左往右的顺序, 新的值会覆盖旧的值.<br />
variables_order = &#8220;EGPCS&#8221;</p>
<p>; 是否将EGPCS变量注册成为全局变量.<br />
; 如果你不希望由于用户数据而导致你脚本的全局变量变得凌乱,你需要关闭此选项<br />
; 这个一般随着 track_vars 打开 &#8211; 在这种情况下你能够通过$HTTP_*_VARS[]存取所有的GPC变量.<br />
;<br />
; 你应该努力写好脚本这样就不必打开register_globals<br />
; 如果代码不是经过详细的斟酌,那将变量作为全局使用可能很容易导致潜在的安全漏洞.<br />
register_globals = Off</p>
<p>; 是否注册老形式的输入数组, HTTP_GET_VARS 和相关数组<br />
; 如果你不使用他们,建议为了提高性能关闭他们.<br />
register_long_arrays = On</p>
<p>; 此指令让PHP确认是否申明 argv&amp;argc 变量 (这些变量会包含GET信息).<br />
; 如果你不使用这些变量,为了提升性能应该关闭此选项.<br />
register_argc_argv = On</p>
<p>; 当打开此项, SERVER 和 ENV 变量将在第一次被使用时而不是脚本一开始时创建(运行时)<br />
; 如果这些变量在脚本中没有被使用过, 打开此项会增加一点性能.<br />
; 为了使此指令有效,PHP指令 register_globals, register_long_arrays,<br />
; 以及 register_argc_argv 必须被关闭.<br />
auto_globals_jit = On</p>
<p>; PHP可以接受的最大的POST数据大小.<br />
post_max_size = 8M</p>
<p>; Magic quotes<br />
;</p>
<p>; 针对GET/POST/Cookie数据打开Magic quotes.<br />
magic_quotes_gpc = On</p>
<p>; 针对实时产生的数据打开Magic quotes, 例如从SQL获取的数据, 从exec()返回的数据等等.<br />
magic_quotes_runtime = Off</p>
<p>; 使用 Sybase 风格的 magic quotes (使用&#8221;来引导&#8217;替代\&#8217;).<br />
magic_quotes_sybase = Off</p>
<p>; 在任何PHP文档之前或之后自动增加文件.<br />
auto_prepend_file =<br />
auto_append_file =</p>
<p>; 和 4.0b4一样, PHP 总是使用默认在头 Content-type: 的编码输出字符.<br />
; 将其设置为空可以禁用发送字符集.<br />
;<br />
; PHP内建默认为text/html<br />
default_mimetype = &#8220;text/html&#8221;<br />
;default_charset = &#8220;iso-8859-1&#8243;</p>
<p>; 总是填充 $HTTP_RAW_POST_DATA 变量.<br />
;always_populate_raw_post_data = On<br />
;;;;;;;;;;;;;;;;;;;;;;;;;<br />
; 路径和目录 ;<br />
;;;;;;;;;;;;;;;;;;;;;;;;;</p>
<p>; UNIX: &#8220;/path1:/path2&#8243;<br />
;include_path = &#8220;.:/php/includes&#8221;<br />
;<br />
; Windows: &#8220;\path1;\path2&#8243;<br />
;include_path = &#8220;.;c:\php\includes&#8221;</p>
<p>; PHP页面的根路径, 只有非空时有效.<br />
; 如果PHP没有使用FORCE_REDIRECT来编译, 如果你将php作为CGI运行在任何web服务器下(除了IIS)的话,你必须设置doc_root<br />
; 针对安全问题查看文档.  一种替代方案是使用下面的cgi.force_redirect<br />
doc_root =</p>
<p>; PHP使用/~username打开脚本的目录,非空时才有效.<br />
user_dir =</p>
<p>; 可加载的扩展(模块)的目录位置.<br />
extension_dir = &#8220;./&#8221;</p>
<p>; 是否启用 dl() 函数.  dl() 函数无法正常的在多线程服务下运行, 例如IIS或者Zeus, 并在在这些服务软件下会自动禁用.<br />
enable_dl = On</p>
<p>; 在绝大多数web服务器下,cgi.force_redirect 对于提供安全执行PHP作为CGI来说是很有必要的.<br />
; 没有配置的情况下,PHP会默认打开此项.<br />
; 你可以在这里关闭此项并且自己承担风险<br />
; **你可以在IIS安全的关闭此项,事实上,你必须关闭此项.**<br />
; cgi.force_redirect = 1</p>
<p>; 如果 cgi.nph 被打开,就会强制CGI在每个请求时发送Status: 200.<br />
; cgi.nph = 1</p>
<p>; 如果cgi.force_redirect被打开,并且你没有在Apache或者Netscape(iPlanet) web服务器下运行,<br />
; 你也许需要设置一个环境变量名让PHP来查找让其可以获取后继续执行. 设置此变量可能引起安全问题, 在设置之前请先了解可能引起的后果.<br />
; cgi.redirect_status_env = ;</p>
<p>; cgi.fix_pathinfo 为CGI提供 *真实* PATH_INFO/PATH_TRANSLATED 支持. <br />
; PHP的预处理行为是设置 PATH_TRANSLATED 到 SCRIPT_FILENAME, 并且不去猜测 PATH_INFO 是什么.<br />
; 想获取关于 PATH_INFO 更多的信息, 查看 cgi 规范. <br />
; 将此值设置为1会引起PHP CGI修正它的路径来符合规范.<br />
; 设置为0会引起PHP类似前面的行为. 默认是1. 你应该修正你的脚本来使用 SCRIPT_FILENAME 而不是 PATH_TRANSLATED.<br />
; cgi.fix_pathinfo=0</p>
<p>; 在IIS下的FastCGI (在基于 WINNT 的操作系统下) 支持莫让呼叫客户端的安全令牌的能力.<br />
; 这使得IIS能够定义其下运行的安全上下文.<br />
; 在Apache下的mod_fastcgi 目前不支持此特性 (03/17/2002)<br />
; 如果运行在IIS下设置为1. 默认是0.<br />
; fastcgi.impersonate = 1;</p>
<p>; 关闭通过 FastCGI 连接的日志<br />
; fastcgi.logging = 0</p>
<p>; cgi.rfc2616_headers 配置选项告知 PHP 当发送HTTP响应代码时使用什么类型的头<br />
; 如果设置为0,PHP发送被Apache支持的 Status: 头信息.<br />
; 当设置为1, PHP会发送 RFC2616 兼容的头信息.<br />
; 默认为0.<br />
; cgi.rfc2616_headers = 0<br />
;;;;;;;;;;;;;;;;<br />
; 文件上传 ;<br />
;;;;;;;;;;;;;;;;</p>
<p>; 是否允许HTTP文件上传.<br />
file_uploads = On</p>
<p>; 对于HTTP上传文件的临时文件目录 (如果没有指定则会使用系统默认).<br />
;upload_tmp_dir =</p>
<p>; 允许上传的最大文件大小.<br />
upload_max_filesize = 2M<br />
;;;;;;;;;;;;;;;;;;<br />
; Fopen 包装 ;<br />
;;;;;;;;;;;;;;;;;;</p>
<p>; 是否允许将URL作为文件 (例如 http:// 或者 ftp://) .<br />
allow_url_fopen = On</p>
<p>; 是否允许 include/require 将URL作为文件 (例如 http:// 或者 ftp://) .<br />
allow_url_include = Off</p>
<p>; 定义匿名ftp密码 (你的电子邮件地址)<br />
;from=&#8221;<a href="mailto:john@doe.com">john@doe.com</a>&#8221;</p>
<p>; 定义 User-Agent 字符串<br />
; user_agent=&#8221;PHP&#8221;</p>
<p>; 定义基于流的socket接口的超时时间 (秒)<br />
default_socket_timeout = 60</p>
<p>; 如果你的脚本必须处理从 Macintosh 系统来的文件,<br />
; 或者你运行在一台Mac并且需要从unix或者win32系统上处理文件,<br />
; 设置此标志会引起PHP自动检测这些文件的EOL字符,这样fgets() 和 file() 就可以不用管文件的来源而直接处理了.<br />
; auto_detect_line_endings = Off<br />
;;;;;;;;;;;;;;;;;;;;;;<br />
; 动态扩展 ;<br />
;;;;;;;;;;;;;;;;;;;;;;<br />
;<br />
; 如果你希望扩展自动加载, 使用下列语法:<br />
;<br />
;   extension=modulename.extension<br />
;<br />
; 例如,在Windows系统上:<br />
;<br />
;   extension=msql.dll<br />
;<br />
; &#8230; 或者在 UNIX 下:<br />
;<br />
;   extension=msql.so<br />
;<br />
; 注意: 这里应该只是模块的名字;<br />
; 这里不需要模块的目录信息.<br />
; 使用上面的 extension_dir 指令来指定扩展的位置.<br />
; Windows Extensions<br />
; 注意:已经内建了ODBC支持,所以不需要针对ODBC的dll.<br />
; 注意:许多DLL文件位于 extensions/ (PHP 4) 或者 ext/ (PHP 5)目录中,和分割的PECL DLL下载在一起 (PHP 5).<br />
; 确定设置了正确的 extension_dir 指令.</p>
<p>;extension=php_bz2.dll<br />
;extension=php_curl.dll<br />
;extension=php_dba.dll<br />
;extension=php_dbase.dll<br />
;extension=php_exif.dll<br />
;extension=php_fdf.dll<br />
;extension=php_gd2.dll<br />
;extension=php_gettext.dll<br />
;extension=php_gmp.dll<br />
;extension=php_ifx.dll<br />
;extension=php_imap.dll<br />
;extension=php_interbase.dll<br />
;extension=php_ldap.dll<br />
;extension=php_mbstring.dll<br />
;extension=php_mcrypt.dll<br />
;extension=php_mhash.dll<br />
;extension=php_mime_magic.dll<br />
;extension=php_ming.dll<br />
;extension=php_msql.dll<br />
;extension=php_mssql.dll<br />
;extension=php_mysql.dll<br />
;extension=php_mysqli.dll<br />
;extension=php_oci8.dll<br />
;extension=php_openssl.dll<br />
;extension=php_pdo.dll<br />
;extension=php_pdo_firebird.dll<br />
;extension=php_pdo_mssql.dll<br />
;extension=php_pdo_mysql.dll<br />
;extension=php_pdo_oci.dll<br />
;extension=php_pdo_oci8.dll<br />
;extension=php_pdo_odbc.dll<br />
;extension=php_pdo_pgsql.dll<br />
;extension=php_pdo_sqlite.dll<br />
;extension=php_pgsql.dll<br />
;extension=php_pspell.dll<br />
;extension=php_shmop.dll<br />
;extension=php_snmp.dll<br />
;extension=php_soap.dll<br />
;extension=php_sockets.dll<br />
;extension=php_sqlite.dll<br />
;extension=php_sybase_ct.dll<br />
;extension=php_tidy.dll<br />
;extension=php_xmlrpc.dll<br />
;extension=php_xsl.dll<br />
;extension=php_zip.dll</p>
<p>;;;;;;;;;;;;;;;;;;;<br />
; 模块设置 ;<br />
;;;;;;;;;;;;;;;;;;;</p>
<p>[Date]<br />
; 定义date函数使用的默认时区<br />
;date.timezone =</p>
<p>;date.default_latitude = 31.7667<br />
;date.default_longitude = 35.2333</p>
<p>;date.sunrise_zenith = 90.583333<br />
;date.sunset_zenith = 90.583333</p>
<p>[filter]<br />
;filter.default = unsafe_raw<br />
;filter.default_flags =</p>
<p>[iconv]<br />
;iconv.input_encoding = ISO-8859-1<br />
;iconv.internal_encoding = ISO-8859-1<br />
;iconv.output_encoding = ISO-8859-1</p>
<p>[sqlite]<br />
;sqlite.assoc_case = 0</p>
<p>[xmlrpc]<br />
;xmlrpc_error_number = 0<br />
;xmlrpc_errors = 0</p>
<p>[Pcre]<br />
;PCRE 库反响追踪限制.<br />
;pcre.backtrack_limit=100000</p>
<p>;PCRE 库递归限制.<br />
;请注意如果你设置此项到一个很高的值, 你可能耗尽所有的可用的进程堆并且最终弄宕PHP(由于到达了操作系统强制的堆大小的限制).<br />
;pcre.recursion_limit=100000</p>
<p>[Syslog]<br />
; 是否定义不同的syslog变量 (例如. $LOG_PID,<br />
; $LOG_CRON, 等等.).  关闭此选项对性能有益.<br />
; 在运行时, 你可以调用 define_syslog_variables() 函数来定义这些变量.<br />
define_syslog_variables  = Off</p>
<p>[mail function]<br />
; 针对Win32.<br />
SMTP = localhost<br />
smtp_port = 25</p>
<p>; 针对Win32.<br />
;sendmail_from = <a href="mailto:me@example.com">me@example.com</a></p>
<p>; 针对Unix.  可以支持参数 (默认: &#8220;sendmail -t -i&#8221;).<br />
;sendmail_path =</p>
<p>; 强制额外的指定的参数被作为扩展参数传送给sendmail执行文件.<br />
; 这些参数总是替代mail()函数的第五个参数值, 甚至是在安全模式内.<br />
;mail.force_extra_parameters =</p>
<p>[SQL]<br />
sql.safe_mode = Off</p>
<p>[ODBC]<br />
;odbc.default_db    =  目前无效<br />
;odbc.default_user  =  目前无效<br />
;odbc.default_pw    =  目前无效</p>
<p>; 允许或阻止持久连接.<br />
odbc.allow_persistent = On</p>
<p>; 在重用前检查连接是否可用.<br />
odbc.check_persistent = On</p>
<p>; 持久连接的最大数目.  -1 意味着没有限制.<br />
odbc.max_persistent = -1</p>
<p>; 最大连接数 (持久 + 非持久).  -1 意味着没有限制.<br />
odbc.max_links = -1</p>
<p>; 长字段处理.  返回变量的字节数.  0 意味着略过.<br />
odbc.defaultlrl = 4096</p>
<p>; 二进制数据处理. 0 意味着略过, 1按照实际返回, 2 转换到字符.<br />
; 查看 odbc_binmode 和 odbc_longreadlen 的文档来获取针对 uodbc.defaultlrl 和 uodbc.defaultbinmode的解释<br />
odbc.defaultbinmode = 1</p>
<p>[MySQL]<br />
; 允许或阻止持久连接.<br />
mysql.allow_persistent = On</p>
<p>; 持久连接的最大数目.  -1 意味着没有限制.<br />
mysql.max_persistent = -1</p>
<p>; 最大连接数 (持久 + 非持久).  -1 意味着没有限制.<br />
mysql.max_links = -1</p>
<p>; mysql_connect()默认的端口号.  如果没有设置, mysql_connect() 会使用 $MYSQL_TCP_PORT<br />
; 或者 位于/etc/services的 mysql-tcp 入口或者编译时定义的MYSQL_PORT 值(按照此顺序查找).<br />
; Win32 只会查找MYSQL_PORT值.<br />
mysql.default_port =</p>
<p>; 对于本地MySQL连接的默认socket名称. 如果为空, 则使用MySQL内建默认值.<br />
mysql.default_socket =</p>
<p>; mysql_connect() 的默认host值(在安全模式中不会生效).<br />
mysql.default_host =</p>
<p>; mysql_connect() 的默认user值(在安全模式中不会生效).<br />
mysql.default_user =</p>
<p>; mysql_connect() 的默认password值(在安全模式中不会生效).<br />
; 注意在此文件中保存密码一般来说是 *糟糕* 的主义.<br />
; *任何* 使用PHP的用户可以执行 &#8216;echo get_cfg_var(&#8220;mysql.default_password&#8221;)<br />
; 并且获取到此密码! 而且理所当然, 任何有对此文件读权限的用户都可以获取到此密码.<br />
mysql.default_password =</p>
<p>; 连接超时的最大时间 (秒) , -1 意味着没有限制.<br />
mysql.connect_timeout = 60</p>
<p>; 追踪模式. 当 trace_mode 被打开 (=On), table/index 扫描的警告和SQL错误会被显示出来.<br />
mysql.trace_mode = Off</p>
<p>[MySQLi]</p>
<p>; 最大连接数.  -1 意味着没有限制.<br />
mysqli.max_links = -1</p>
<p>; mysqli_connect()默认的端口号.  如果没有设置, mysql_connect() 会使用 $MYSQL_TCP_PORT<br />
; 或者 位于/etc/services的 mysql-tcp 入口或者编译时定义的MYSQL_PORT 值(按照此顺序查找).<br />
; Win32 只会查找MYSQL_PORT值.<br />
mysqli.default_port = 3306</p>
<p>; 对于本地MySQL连接的默认socket名称. 如果为空, 则使用MySQL内建默认值.<br />
mysqli.default_socket =</p>
<p>; mysqli_connect() 的默认host值(在安全模式中不会生效).<br />
mysqli.default_host =</p>
<p>; mysqli_connect() 的默认user值(在安全模式中不会生效).<br />
mysqli.default_user =</p>
<p>; mysqli_connect() 的默认password值(在安全模式中不会生效).<br />
; 注意在此文件中保存密码一般来说是 *糟糕* 的主义.<br />
; *任何* 使用PHP的用户可以执行 &#8216;echo get_cfg_var(&#8220;mysqli.default_password&#8221;)<br />
; 并且获取到此密码! 而且理所当然, 任何有对此文件读权限的用户都可以获取到此密码.<br />
mysqli.default_pw =</p>
<p>; 允许或阻止持久连接.<br />
mysqli.reconnect = Off</p>
<p>[mSQL]<br />
; 允许或阻止持久连接.<br />
msql.allow_persistent = On</p>
<p>; 持久连接的最大数目.  -1 意味着没有限制.<br />
msql.max_persistent = -1</p>
<p>; 最大连接数 (持久 + 非持久).  -1 意味着没有限制.<br />
msql.max_links = -1</p>
<p>[OCI8]<br />
; 打开使用外部认证的授权连接 (OCI_SYSOPER, OCI_SYSDBA)<br />
;oci8.privileged_connect = Off</p>
<p>; 连接: 每个进程的持久OCI8连接的最大数, -1 意味着没有限制.<br />
;oci8.max_persistent = -1</p>
<p>; 连接: 一个进程允许保持一个空闲持久连接的最大秒数.<br />
; -1意味着空闲持久连接会永远被保持.<br />
;oci8.persistent_timeout = -1</p>
<p>; 连接: 当oci_pconnect() 检测一个连接是否有效时每次发起ping之间必须通过的秒数.<br />
; 当设置为0后, 每个oci_pconnect() 会发起一个ping. Using -1 完全关闭ping.<br />
;oci8.ping_interval = 60</p>
<p>; 调优: 此选项打开声明缓冲(statement cache), 并且指定缓冲多少声明. 使用0关闭声明缓冲.<br />
;oci8.statement_cache_size = 20</p>
<p>; 调优: 打开声明预取(statement prefetch) 并且设置自动在声明执行后被取到行的数量.<br />
;oci8.default_prefetch = 10</p>
<p>; 兼容性: 设置为On 意味着 oci_close() 不会关闭 oci_connect() 和 oci_new_connect() 的连接.<br />
;oci8.old_oci_close_semantics = Off</p>
<p>[PostgresSQL]<br />
; 允许或阻止持久连接.<br />
pgsql.allow_persistent = On</p>
<p>; 总是在 pg_pconnect() 时检测断开的持久连接.<br />
; 自动重置特性会引起一点开销.<br />
pgsql.auto_reset_persistent = Off</p>
<p>; 持久连接的最大数目.  -1 意味着没有限制.<br />
pgsql.max_persistent = -1</p>
<p>; 最大连接数 (持久 + 非持久).  -1 意味着没有限制.<br />
pgsql.max_links = -1</p>
<p>; 是否忽略 PostgreSQL 后端通告消息.<br />
; 通告消息记录会需要一点开销.<br />
pgsql.ignore_notice = 0</p>
<p>; 是否记录 PostgreSQL 后端通告消息.<br />
; 除非 pgsql.ignore_notice=0, 否则模块无法记录通告消息<br />
pgsql.log_notice = 0</p>
<p>[Sybase]<br />
; 允许或阻止持久连接.<br />
sybase.allow_persistent = On</p>
<p>; 持久连接的最大数目.  -1 意味着没有限制.<br />
sybase.max_persistent = -1</p>
<p>; 最大连接数 (持久 + 非持久).  -1 意味着没有限制.<br />
sybase.max_links = -1</p>
<p>;sybase.interface_file = &#8220;/usr/sybase/interfaces&#8221;</p>
<p>; 显示出的消息最小严重程度.<br />
sybase.min_error_severity = 10</p>
<p>; 显示出的消息最小严重程度.<br />
sybase.min_message_severity = 10</p>
<p>; 兼容老版本PHP 3.0的模式.<br />
; 如果设为 on, 会引起 PHP 自动绑定结果记录的类型到Sybase的类型,而不是将他们全部按照字符串处理.<br />
; 此兼容模式可能不会永久存在, 所以最好尝试在你代码中需要的地方作出必要的修改, 然后关闭此选项.<br />
sybase.compatability_mode = Off</p>
<p>[Sybase-CT]<br />
; 允许或阻止持久连接.<br />
sybct.allow_persistent = On</p>
<p>; 持久连接的最大数目.  -1 意味着没有限制.<br />
sybct.max_persistent = -1</p>
<p>; 最大连接数 (持久 + 非持久).  -1 意味着没有限制.<br />
sybct.max_links = -1</p>
<p>; 显示出的错误最小严重程度.<br />
sybct.min_server_severity = 10</p>
<p>; 显示出的消息最小严重程度.<br />
sybct.min_client_severity = 10</p>
<p>[bcmath]<br />
; 所有bcmath函数的小数位数<br />
bcmath.scale = 0</p>
<p>[browscap]<br />
;browscap = extra/browscap.ini</p>
<p>[Informix]<br />
; 对于 ifx_connect() 的默认host (不会在安全模式被应用).<br />
ifx.default_host =</p>
<p>; 对于 ifx_connect() 的默认user (不会在安全模式被应用).<br />
ifx.default_user =</p>
<p>; 对于 ifx_connect() 的默认password (不会在安全模式被应用).<br />
ifx.default_password =</p>
<p>; 允许或阻止持久连接.<br />
ifx.allow_persistent = On</p>
<p>; 持久连接的最大数目.  -1 意味着没有限制.<br />
ifx.max_persistent = -1</p>
<p>; 最大连接数 (持久 + 非持久).  -1 意味着没有限制.<br />
ifx.max_links = -1</p>
<p>; 如果设为 on, select 声明返回 text 段的内容而不是它的id.<br />
ifx.textasvarchar = 0</p>
<p>; 如果设为 on, select 声明返回 byte 段的内容而不是它的id.<br />
ifx.byteasvarchar = 0</p>
<p>; 固定长度字符列的尾部空格会被截去.  可能对 Informix SE 用户有帮助.<br />
ifx.charasvarchar = 0</p>
<p>; 如果设为 on, text 和 byte 段会被dump到一个文件而不是在内存中保留它们.<br />
ifx.blobinfile = 0</p>
<p>; NULL会被作为一个空字符串返回, 除非被设为1. 如果设为1, NULL会被作为字符串&#8217;NULL&#8217;返回.<br />
ifx.nullformat = 0</p>
<p>[Session]<br />
; 用来存储/获取数据的处理方法.<br />
session.save_handler = files</p>
<p>; 传送到save_handler的参数.  在使用文件的情况下, 这里是数据文件被保存的路径.<br />
; 注意: Windows 用户必须改变此值来使用PHP的会话函数.<br />
;<br />
; 和在 4.0.1一样, 你可以定义如下路径:<br />
;<br />
;     session.save_path = &#8220;N;/path&#8221;<br />
;<br />
; 这里的 N 是一个整数.  使用此参数会在目录内建立一个N层深度的子目录用来保存session文件,<br />
; 而不是将所有session文件保存在同一个/path目录内. <br />
; 这对你或当你的操作系统在一个目录内保存太多文件时出现问题很有帮助.<br />
; 并且对于处理大量session的服务器提供更高的效率.<br />
;<br />
; 注意 1: PHP不会自动创建目录结构. 你可以使用在ext/session目录内的脚本来创建目录结构.<br />
; 注意 2: 如果你选择使用子目录来保存session,请检查下面关于垃圾回收的配置段<br />
;<br />
; 文件存储模块默认使用600模式来创建文件,在使用中你可以改变此选项<br />
;<br />
;     session.save_path = &#8220;N;MODE;/path&#8221;<br />
;<br />
; 这里的MODE由8进制来表示. 注意这里不会覆盖进程的umask.<br />
;session.save_path = &#8220;/tmp&#8221;</p>
<p>; 是否使用cookie.<br />
session.use_cookies = 1</p>
<p>;session.cookie_secure =</p>
<p>; 这个选项允许管理员去保护那些在URL中传送session id的用户免于被攻击<br />
; 默认是 0.<br />
; session.use_only_cookies = 1</p>
<p>; session的名称 (作为cookie名称来使用).<br />
session.name = PHPSESSID</p>
<p>; 在请求开始的时候初始化session.<br />
session.auto_start = 0</p>
<p>; cookie的生存秒数,或者如果为0就直到浏览器重启.<br />
session.cookie_lifetime = 0</p>
<p>; cookie有效的路径.<br />
session.cookie_path = /</p>
<p>; cookie有效的域名.<br />
session.cookie_domain =</p>
<p>; 是否将httpOnly标志增加到cookie上, 增加后则cookie无法被浏览器的脚本语言(例如JavaScript)存取.<br />
session.cookie_httponly =</p>
<p>; 用于序列化数据的处理器. php是标准的PHP序列化器.<br />
session.serialize_handler = php</p>
<p>; 定义&#8217;垃圾回收&#8217;进程在每次session初始化时开始的比例.<br />
; 比例由 gc_probability/gc_divisor来得出,<br />
; 例如. 1/100 意味着在每次请求时有1%的机会启动&#8217;垃圾回收&#8217;进程.</p>
<p>session.gc_probability = 1<br />
session.gc_divisor     = 100</p>
<p>; 在经过以下秒数之后, 存储的数据会被认为是&#8217;垃圾&#8217;并且被垃圾回收进程清理掉.<br />
session.gc_maxlifetime = 1440</p>
<p>; 注意: 如果你使用子目录选项来保存session文件<br />
;       (查看在上面的session.save_path), 那么垃圾回收就 *不会* 自动发生.<br />
;       你需要通过一个shell脚本,cron或者其他方法来自行处理垃圾回收.<br />
;       例如, 下面的脚本相当于将session.gc_maxlifetime设置为 1440 (1440 秒 = 24 分钟):<br />
;          cd /path/to/sessions; find -cmin +24 | xargs rm</p>
<p>; PHP 4.2 和更早版本有一个未公开的 特性/bug , 此特性允许你在全局初始化一个session变量,即便 register_globals 已经被关闭.<br />
; 如果此特性被使用,PHP 4.3 和更早版本会警告你.<br />
; 你可以关闭此特性并且隔离此警告. 这时候,如果打开bug_compat_42,那此警告只是被显示出来.</p>
<p>session.bug_compat_42 = 1<br />
session.bug_compat_warn = 1</p>
<p>; 检查HTTP Referer来防止带有id的外部URL.<br />
; HTTP_REFERER 必须包含从session来的这个字段才会被认为是合法的.<br />
session.referer_check =</p>
<p>; 从此文件读取多少字节.<br />
session.entropy_length = 0</p>
<p>; 在这里指定创建session id.<br />
session.entropy_file =</p>
<p>;session.entropy_length = 16</p>
<p>;session.entropy_file = /dev/urandom</p>
<p>; 设置为 {nocache,private,public,} 来决定HTTP缓冲的类型<br />
; 留空则防止发送 anti-caching 头.<br />
session.cache_limiter = nocache</p>
<p>; 文档在n分钟之后过期.<br />
session.cache_expire = 180</p>
<p>; trans sid 支持默认关闭.<br />
; 使用 trans sid 可能让你的用户承担安全风险.<br />
; 使用此项必须小心.<br />
; &#8211; 用户也许通过email/irc/其他途径发送包含有效的session ID的URL给其他人.<br />
; &#8211; 包含有效session ID的URL可能被存放在容易被公共存取的电脑上.<br />
; &#8211; 用户可能通过在浏览器历史记录或者收藏夹里面的包含相同的session ID的URL来访问你的站点.<br />
session.use_trans_sid = 0</p>
<p>; 选择hash方法<br />
; 0: MD5   (128 bits)<br />
; 1: SHA-1 (160 bits)<br />
session.hash_function = 0</p>
<p>; 当转换二进制hash数据到可读形式时,每个字符保存时有几位.<br />
;<br />
; 4 bits: 0-9, a-f<br />
; 5 bits: 0-9, a-v<br />
; 6 bits: 0-9, a-z, A-Z, &#8220;-&#8221;, &#8220;,&#8221;<br />
session.hash_bits_per_character = 4</p>
<p>; URL rewriter会在已经定义的一组HTML标签内查找URL.<br />
; form/fieldset 是特殊字符; 如果你在这里包含他们, rewriter会增加一个包含信息的隐藏&lt;input&gt;字段否则就是在URL中附加信息.<br />
; 如果你你想遵守XHTML, 删除form的入口.<br />
; 注意 所有合法的入口都需要一个&#8221;=&#8221;符号, 甚至是没有任何值的.<br />
url_rewriter.tags = &#8220;a=href,area=href,frame=src,input=src,form=,fieldset=&#8221;</p>
<p>[MSSQL]<br />
; 允许或阻止持久连接.<br />
mssql.allow_persistent = On</p>
<p>; 持久连接的最大数目.  -1 意味着没有限制.<br />
mssql.max_persistent = -1</p>
<p>; 最大连接数 (持久 + 非持久).  -1 意味着没有限制.<br />
mssql.max_links = -1</p>
<p>; 显示出的错误最小严重程度.<br />
mssql.min_error_severity = 10</p>
<p>; 显示出的消息最小严重程度.<br />
mssql.min_message_severity = 10</p>
<p>; PHP 3.0 老版本的兼容模式.<br />
mssql.compatability_mode = Off</p>
<p>; 连接超时<br />
;mssql.connect_timeout = 5</p>
<p>; 查询超时<br />
;mssql.timeout = 60</p>
<p>; 有效范围 0 &#8211; 2147483647.  默认 = 4096.<br />
;mssql.textlimit = 4096</p>
<p>; 有效范围 0 &#8211; 2147483647.  默认 = 4096.<br />
;mssql.textsize = 4096</p>
<p>; 每批记录的数量限制.  0 = 所有记录在一批内.<br />
;mssql.batchsize = 0</p>
<p>; 指定 datetime 和 datetim4 栏如何返回<br />
; On =&gt; 返回数据转换到SQL服务器设置的格式<br />
; Off =&gt; 使用 YYYY-MM-DD hh:mm:ss 返回<br />
;mssql.datetimeconvert = On</p>
<p>; 当连接到服务器时使用NT验证<br />
mssql.secure_connection = Off</p>
<p>; 指定最大进程数. -1 = 库默认<br />
; msdlib 默认 25<br />
; FreeTDS 默认 4096<br />
;mssql.max_procs = -1</p>
<p>; 指定客户端字符集.<br />
; 如果为空或者没有指定,客户端字符集将会使用freetds.conf的配置<br />
; 只有和FreeTDS编译时会被使用<br />
;mssql.charset = &#8220;ISO-8859-1&#8243;</p>
<p>[Assertion]<br />
; 断言(expr); 默认打开.<br />
;assert.active = On</p>
<p>; 对于每个失败断言发起一个PHP警告.<br />
;assert.warning = On</p>
<p>; 默认不要保释.<br />
;assert.bail = Off</p>
<p>; 如果断言失败则调用用户自定义函数.<br />
;assert.callback = 0</p>
<p>; 使用当前 error_reporting() Eval一个表达式.  如果你想要在eval()附近error_reporting(0) ,那设置为true.<br />
;assert.quiet_eval = 0</p>
<p>[COM]<br />
; 包含GUID,IID或者TypeLibs的文件的文件名的文件的路径<br />
;com.typelib_file =<br />
; 允许 Distributed-COM 调用<br />
;com.allow_dcom = true<br />
; 自动注册位于com_load()函数的组件typlib的常量<br />
;com.autoregister_typelib = true<br />
; 注册常量大小写敏感<br />
;com.autoregister_casesensitive = false<br />
; 当有重复常量注册时显示警告<br />
;com.autoregister_verbose = true</p>
<p>[mbstring]<br />
; 内部字符表示的语言.<br />
;mbstring.language = Japanese</p>
<p>; 内部/脚本编码.<br />
; 部分编码无法作为内部编码使用.<br />
; (例如. SJIS, BIG5, ISO-2022-*)<br />
;mbstring.internal_encoding = EUC-JP</p>
<p>; http 输入编码.<br />
;mbstring.http_input = auto</p>
<p>; http 输出编码. mb_output_handler 必须作为函数被注册为输出缓冲<br />
;mbstring.http_output = SJIS</p>
<p>; 按照mbstring.internal_encoding的设置打开自动编码转换<br />
; 当设置为On时,输入字符被转换为内部编码.<br />
; 注意: 不要针对可移植库/应用使用自动编码转换.<br />
;mbstring.encoding_translation = Off</p>
<p>; 自动编码检测序列<br />
; 自动意味着<br />
;mbstring.detect_order = auto</p>
<p>; 当无法将字符从一种转换到另一种时使用的置换符号<br />
;mbstring.substitute_character = none;</p>
<p>; 使用mbstring函数 覆盖(替换) 单字节函数.<br />
; mail(), ereg(), 等等都会被 mb_send_mail(), mb_ereg() 等等覆盖,<br />
; 可以取的值是 0,1,2,4 或者他们的组合.<br />
; 例如, 7 就是覆盖所有函数.<br />
; 0: 不覆盖<br />
; 1: 覆盖 mail() 函数<br />
; 2: 覆盖 str*() 函数<br />
; 4: 覆盖 ereg*() 函数<br />
;mbstring.func_overload = 0</p>
<p>[FrontBase]<br />
;fbsql.allow_persistent = On<br />
;fbsql.autocommit = On<br />
;fbsql.show_timestamp_decimals = Off<br />
;fbsql.default_database =<br />
;fbsql.default_database_password =<br />
;fbsql.default_host =<br />
;fbsql.default_password =<br />
;fbsql.default_user = &#8220;_SYSTEM&#8221;<br />
;fbsql.generate_warnings = Off<br />
;fbsql.max_connections = 128<br />
;fbsql.max_links = 128<br />
;fbsql.max_persistent = -1<br />
;fbsql.max_results = 128</p>
<p>[gd]<br />
; 告知jpeg解码器libjpeg警告并且尝试创建一个gd图像. 此警告会被作为一个通告显示<br />
; 默认为关闭<br />
;gd.jpeg_ignore_warning = 0</p>
<p>[exif]<br />
; Exif UNICODE 用户注释会被作为UCS-2BE/UCS-2LE 和 JIS 来进行 JIS处理.<br />
; 当 mbstring.internal_encoding 设置为空,如果有 mbstring 支持,则会自动转换到给出的对应编码设置的编码.<br />
; 对于解码设置你可以在motorola和intel字符序列上进行选择. 解码设置不能设置为空.<br />
;exif.encode_unicode = ISO-8859-15<br />
;exif.decode_unicode_motorola = UCS-2BE<br />
;exif.decode_unicode_intel    = UCS-2LE<br />
;exif.encode_jis =<br />
;exif.decode_jis_motorola = JIS<br />
;exif.decode_jis_intel    = JIS</p>
<p>[Tidy]<br />
; 当调用tidy时,默认指向tidy配置文件的路径<br />
;tidy.default_config = /usr/local/lib/php/default.tcfg</p>
<p>; tidy是否自动清除和修复输出?<br />
; 警告: 不要在你产生非html内容时使用此项,例如产生动态图片时<br />
tidy.clean_output = Off</p>
<p>[soap]<br />
; 打开或关闭WSDL缓冲特性.<br />
soap.wsdl_cache_enabled=1<br />
; 设置SOAP扩展存放缓冲文件的目录.<br />
soap.wsdl_cache_dir=&#8221;/tmp&#8221;<br />
; (存活时间) 设置当缓冲文件被用来替换原有缓冲文件的秒数.<br />
soap.wsdl_cache_ttl=86400</p>
<p>; Local Variables:<br />
; tab-width: 4<br />
; End:</p>
<p>原文：<a href="http://www.phpv.net/html/1680.html">http://www.phpv.net/html/1680.html</a></p>
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		</item>
		<item>
		<title>如何在repair filesystem下面修改文件</title>
		<link>http://226617.cn/archives/487.htm</link>
		<comments>http://226617.cn/archives/487.htm#comments</comments>
		<pubDate>Thu, 26 Mar 2009 15:04:51 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[linux相关]]></category>
		<category><![CDATA[linux]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=487</guid>
		<description><![CDATA[今天在把一台cdn重新安装成64位系统，vm上划了台新机器就把挂在老的机器上的存储lun删除后挂在新的机器上，结果下午准备把老的cdn拿出来测试下squid3.0 结果起到一半由于fstab还有挂载存储lun... ]]></description>
			<content:encoded><![CDATA[<p>今天在把一台cdn重新安装成64位系统，vm上划了台新机器就把挂在老的机器上的存储lun删除后挂在新的机器上，结果下午准备把老的cdn拿出来测试下squid3.0 结果起到一半由于fstab还有挂载存储lun的信息，只能进repair filesystem，打算fstab里面删除挂载存储lun的信息又发现整个文件系统是只读挂载，晕，网上搜了搜，用#mount -o remount / 重新挂载根分区搞定了。</p>
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		</item>
		<item>
		<title>没事不要瞎折腾</title>
		<link>http://226617.cn/archives/483.htm</link>
		<comments>http://226617.cn/archives/483.htm#comments</comments>
		<pubDate>Wed, 25 Mar 2009 15:28:42 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[只谈心情]]></category>
		<category><![CDATA[ips]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=483</guid>
		<description><![CDATA[最近由于打算正式启用电信的cdn服务器，由于电信过来走得是内网专线，直接接的交换机，这样cdn过来的动态请求也是直接走内网了，所以打算把出口改造下把内网专线和移动出口的线路先汇... ]]></description>
			<content:encoded><![CDATA[<p>最近由于打算正式启用电信的cdn服务器，由于电信过来走得是内网专线，直接接的交换机，这样cdn过来的动态请求也是直接走内网了，所以打算把出口改造下把内网专线和移动出口的线路先汇聚到一台3750然后接入到ips。环顾了一下所有相连交换机的连接状况，确保没有问题后，下午开始开工了，本来只要把线拔一下换个地方接接就行了，结果一拔拔出问题来了。原来移动出口是接在ips第三口的，我把线拔下来后接上3750过来的线发现灯不亮，我以为那里搞错了环了就把原来的线接回去还是不亮，晕啊。重启一边ips，发现重启过程中bypass启动后竟然通了，以为好了，没想到启动完第三口又灭了，于是就把ips到内部交换机的第四口的线拔过来试试发现好的，又把3750过来的线接到第四口发现也好的，这时候网络也全通了。感觉是ips问题，打400电话，客服说没碰到过这种情况，建议把ips和后面交换机关了插头拔了等5分钟再开，@%#￥……#&#038;。无奈没办法，只能试试，全部断电，上电，结果问题依然照旧，实在没办法只能把ips的3和4个交换下接上，中途测试了下把1口的线接到3口也不亮。客服说这问题他们要研究下才能给答复。</p>
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		</item>
		<item>
		<title>Plesk for Linux 安装Zend Optimizer</title>
		<link>http://226617.cn/archives/479.htm</link>
		<comments>http://226617.cn/archives/479.htm#comments</comments>
		<pubDate>Wed, 18 Mar 2009 09:10:15 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[linux相关]]></category>
		<category><![CDATA[php相关]]></category>
		<category><![CDATA[php]]></category>
		<category><![CDATA[Plesk]]></category>
		<category><![CDATA[Zend Optimizer]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=479</guid>
		<description><![CDATA[今天在给一台linux 的plesk安装Zend Optimizer，全部默认安装，结果restart apache后php文件没法访问。查看apache的出错日志里面提示PHP Fatal error: [ionCube Loader] The Loader must appear as the first entry in the php.ini f... ]]></description>
			<content:encoded><![CDATA[<p>今天在给一台linux 的plesk安装Zend Optimizer，全部默认安装，结果restart apache后php文件没法访问。查看apache的出错日志里面提示PHP Fatal error: [ionCube Loader] The Loader must appear as the first entry in the php.ini file in Unknown on line 0<br />
后来仔细看了看plesk的php，发现用的是centos自带的php，就找到目录里面看发现是和plesk使用的Ioncube冲突。只要解决下先后加载顺序就行把php.ini里面的：</p>

<div class="wp_syntax"><table><tr><td class="line_numbers"><pre>1
2
3
4
5
6
</pre></td><td class="code"><pre class="ini" style="font-family:monospace;"><span style="color: #000066; font-weight:bold;"><span style="">&#91;</span>Zend<span style="">&#93;</span></span>
zend_extension_manager.optimizer<span style="color: #000066; font-weight:bold;">=</span><span style="color: #660066;">/usr/local/Zend/lib/Optimizer-3.3.0</span>
zend_extension_manager.optimizer_ts<span style="color: #000066; font-weight:bold;">=</span><span style="color: #660066;">/usr/local/Zend/lib/Optimizer_TS-3.3.0</span>
zend_optimizer.version<span style="color: #000066; font-weight:bold;">=</span><span style="color: #660066;">3.3.0</span>
<span style="color: #000099;">zend_extension</span><span style="color: #000066; font-weight:bold;">=</span><span style="color: #660066;">/usr/local/Zend/lib/ZendExtensionManager.so</span>
<span style="color: #000099;">zend_extension_ts</span><span style="color: #000066; font-weight:bold;">=</span><span style="color: #660066;">/usr/local/Zend/lib/ZendExtensionManager_TS.so</span></pre></td></tr></table></div>

<p>剪切然后修改etc/php.d/ioncube-loader.ini 添加到</p>

<div class="wp_syntax"><table><tr><td class="line_numbers"><pre>1
</pre></td><td class="code"><pre class="ini" style="font-family:monospace;"><span style="color: #000099;">zend_extension</span><span style="color: #000066; font-weight:bold;">=</span><span style="color: #660066;">/usr/lib/php/modules//php_ioncube_loader_lin_5.1.so</span></pre></td></tr></table></div>

<p>后面就ok了</p>
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		</item>
		<item>
		<title>nginx gzip无法静态输出http</title>
		<link>http://226617.cn/archives/477.htm</link>
		<comments>http://226617.cn/archives/477.htm#comments</comments>
		<pubDate>Wed, 18 Mar 2009 01:11:27 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[nginx相关]]></category>
		<category><![CDATA[nginx]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=477</guid>
		<description><![CDATA[最近在做nginx+squid2.6，发现静态文件nginx只要gzip后就http header就没有Content-Length，都是Transfer-Encoding chunked，使用gzip_static又必须每个文件预先压缩个gz。 而翻了翻squid手册说squid2.6输出gzip必须满足... ]]></description>
			<content:encoded><![CDATA[<p>最近在做nginx+squid2.6，发现静态文件nginx只要gzip后就http header就没有Content-Length，都是Transfer-Encoding chunked，使用gzip_static又必须每个文件预先压缩个gz。<br />
而翻了翻squid手册说squid2.6输出gzip必须满足2点，1就是有Content-Length，2必须有vary信息。<br />
网上搜了搜一时无法解决</p>
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		</item>
		<item>
		<title>linux ulimit参数介绍</title>
		<link>http://226617.cn/archives/475.htm</link>
		<comments>http://226617.cn/archives/475.htm#comments</comments>
		<pubDate>Thu, 12 Mar 2009 13:53:38 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[linux相关]]></category>
		<category><![CDATA[linux]]></category>
		<category><![CDATA[ulimit]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=475</guid>
		<description><![CDATA[在*NIX将TCP/IP也作为文件来访问，而一般系统默认的访问文件数是1024。如果是在运营级别服务器上面就需要调整系统的最大访问文件数来提高网络并发性能。 调整方法就是ulimit命令，比如ulimit -... ]]></description>
			<content:encoded><![CDATA[<p>在*NIX将TCP/IP也作为文件来访问，而一般系统默认的访问文件数是1024。如果是在运营级别服务器上面就需要调整系统的最大访问文件数来提高网络并发性能。<br />
调整方法就是ulimit命令，比如ulimit -SHn 65535</p>
<p>ulimit 参数介绍:<br />
-H 设置硬件资源限制.<br />
-S 设置软件资源限制.<br />
-a 显示当前所有的资源限制.<br />
-c size:设置core文件的最大值.单位:blocks<br />
-d size:设置数据段的最大值.单位:kbytes<br />
-f size:设置创建文件的最大值.单位:blocks<br />
-l size:设置在内存中锁定进程的最大值.单位:kbytes<br />
-m size:设置可以使用的常驻内存的最大值.单位:kbytes<br />
-n size:设置内核可以同时打开的文件描述符的最大值.单位:n<br />
-p size:设置管道缓冲区的最大值.单位:kbytes<br />
-s size:设置堆栈的最大值.单位:kbytes<br />
-t size:设置CPU使用时间的最大上限.单位:seconds<br />
-v size:设置虚拟内存的最大值.单位:kbytes</p>
<p>一般可以设置 ulimit -SHn 65535<br />
请注意，该命令只在当前shell环境下有效，而且只能由root权限来设置，一般可以放在需要启动服务的命令脚本里，另外，如果你是用root登录来启动服务的话，防止忘记这条命令，一般可以设置在~/.root 下的 .bash_profile 文件或者/etc/rc.local文件中，不建议在/etc/profile 中设置，因为该命令只有root用户有权限将数字增加到超过系统默认的上限（比如 -n 打开文件数 1024 )。</p>
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		</item>
		<item>
		<title>VMware VirtualCenter 2.5升级u4出错</title>
		<link>http://226617.cn/archives/472.htm</link>
		<comments>http://226617.cn/archives/472.htm#comments</comments>
		<pubDate>Thu, 12 Mar 2009 07:24:16 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[vmware相关]]></category>
		<category><![CDATA[VC]]></category>
		<category><![CDATA[VirtualCenter]]></category>
		<category><![CDATA[vmware]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=472</guid>
		<description><![CDATA[今天再把VMware VirtualCenter 2.5从u3升级到u4，备份数据库，升级，升级数据库一切正常。启动重建ha正常，顺便就把机器重启了边，结果重启后发现vc服务起不来了。想找日志看，结果找个日志找了... ]]></description>
			<content:encoded><![CDATA[<p>今天再把VMware VirtualCenter 2.5从u3升级到u4，备份数据库，升级，升级数据库一切正常。启动重建ha正常，顺便就把机器重启了边，结果重启后发现vc服务起不来了。想找日志看，结果找个日志找了半天竟然放在C:\Documents and Settings\All Users\Application Data\VMware\VMware VirtualCenter\Logs<br />
找最后修改的那个日志打开一看</p>

<div class="wp_syntax"><table><tr><td class="line_numbers"><pre>1
2
3
</pre></td><td class="code"><pre class="log" style="font-family:monospace;">[2009-03-12 13:42:01.046 'App' 3064 error] [VpxdReverseProxy] Failed to create https proxy: Resource is already in use: Listen socket: :443
[2009-03-12 13:42:01.046 'App' 3064 error] Failed to intialize VMware VirtualCenter. Shutting down...
[2009-03-12 13:42:01.046 'App' 3064 info] Forcing shutdown of VMware VirtualCenter now</pre></td></tr></table></div>

<p>原来端口给占用了，找出CurrPorts一看原来是上次装的发报警邮件的mailserver自带了个80和443。找到mailserver设置关掉了http和https模块重启机器一切正常。</p>
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		</item>
		<item>
		<title>把博客升级到了2.7.1</title>
		<link>http://226617.cn/archives/470.htm</link>
		<comments>http://226617.cn/archives/470.htm#comments</comments>
		<pubDate>Wed, 11 Mar 2009 13:32:39 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[只谈心情]]></category>
		<category><![CDATA[wordpress]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=470</guid>
		<description><![CDATA[出来好久了一直没升级，自动升级功能由于下载超过php超时时间一直没成功。所以今天抽空手工升级了下。还是用的国内中文团队的增强中文版本http://code.google.com/p/wpcn/downloads/list 升级后竟然... ]]></description>
			<content:encoded><![CDATA[<p>出来好久了一直没升级，自动升级功能由于下载超过php超时时间一直没成功。所以今天抽空手工升级了下。还是用的国内中文团队的增强中文版本http://code.google.com/p/wpcn/downloads/list</p>
<p>升级后竟然白屏，看了php出错日志发现是插件问题删除了admin-area-appearance-tweaks插件就ok了，也不知道是什么插件。<br />
启用了2.7.1增强版自带的几个插件，后台字体舒服多了。</p>
<p>顺便整理下服务器上的插件和主题。感觉现在主题不怎么好看，还得找个顺眼的去</p>
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		</item>
		<item>
		<title>nginx配置文件中的rewrite参数中-f -d -e的使用误解</title>
		<link>http://226617.cn/archives/462.htm</link>
		<comments>http://226617.cn/archives/462.htm#comments</comments>
		<pubDate>Sun, 08 Mar 2009 15:21:54 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[nginx相关]]></category>
		<category><![CDATA[nginx]]></category>
		<category><![CDATA[rewrite]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=462</guid>
		<description><![CDATA[今天在写一个rewrite的时候总是不对，当中用到了文件不存在的判断，如下： 1 2 3 4 if (!-f $request_filename){ rewrite ^(.*)$ http://site.com$1 permanent; break; } 重温这几个参数的含义 -f和!-f用来判断是否存在... ]]></description>
			<content:encoded><![CDATA[<p>今天在写一个rewrite的时候总是不对，当中用到了文件不存在的判断，如下：</p>

<div class="wp_syntax"><table><tr><td class="line_numbers"><pre>1
2
3
4
</pre></td><td class="code"><pre class="nginx" style="font-family:monospace;">if (!-f $request_filename){
     rewrite ^(.*)$ http://site.com$1 permanent;
     break;
}</pre></td></tr></table></div>

<p>重温这几个参数的含义<br />
-f和!-f用来判断是否存在文件<br />
-d和!-d用来判断是否存在目录<br />
-e和!-e用来判断是否存在文件或目录</p>
<p>安装我原来的理解是如果需要判断请求的目录是否存在就用d，比如/dira/<br />
需要判断请求的目录是否存在就用f，比如/dira/filea<br />
如果文件或者目录之一有不存在的话就用e</p>
<p>原来我以为/dira/filea 假如dira和filea都不存在的话随便用那个参数都能匹配<br />
今天经过实际使用发现我完全搞错了，如果真正请求遇到上面这个目录和文件都不存在的话 !-f 和 !-d 是没法匹配的，只能用 !-e 。<br />
正确的解释是<br />
-e和!-e用来判断是否存在文件<span style="color: #ff0000;">和</span>目录</p>
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		</item>
		<item>
		<title>使用iptables防止ssh暴力猜解</title>
		<link>http://226617.cn/archives/460.htm</link>
		<comments>http://226617.cn/archives/460.htm#comments</comments>
		<pubDate>Sat, 07 Mar 2009 14:24:40 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[linux相关]]></category>
		<category><![CDATA[iptables]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=460</guid>
		<description><![CDATA[基于端口，使用iptables的connlimit模块 iptables -I INPUT -p tcp –syn –dport 22 -m connlimit –connlimit-above 2 -j REJECT 一条指令即可以搞掂， –connlimit-above 2表示只允许一个客户开启二个会话,与sshd_config 设置... ]]></description>
			<content:encoded><![CDATA[<p>基于端口，使用iptables的connlimit模块</p>
<p>iptables -I INPUT -p tcp –syn –dport 22 -m connlimit –connlimit-above 2 -j REJECT</p>
<p>一条指令即可以搞掂， –connlimit-above 2表示只允许一个客户开启二个会话,与sshd_config 设置的区别，sshd_config只能设定一个用户最多尝试几次密码</p>
<p>同样也可以设定web服务访问设限</p>
<p>iptables -I INPUT -p tcp –syn –dport 80 -m connlimit –connlimit-above 30 -j REJECT<br />
这样即可</p>
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		</item>
		<item>
		<title>CENTOS 5下双网卡实现网络的高性能HP和高可用HA</title>
		<link>http://226617.cn/archives/458.htm</link>
		<comments>http://226617.cn/archives/458.htm#comments</comments>
		<pubDate>Sat, 07 Mar 2009 14:23:54 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[linux相关]]></category>
		<category><![CDATA[linux]]></category>
		<category><![CDATA[网络]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=458</guid>
		<description><![CDATA[高性能HP和高可用HA网络介面设定都是一样的 cat /etc/sysconfig/network-scripts/ifcfg-bond0 DEVICE=bond0 IPADDR=192.168.10.104 NETMASK=255.255.255.0 ONBOOT=yes BOOTPROTO=none USERCTL=no cat /etc/sysconfig/network-scripts/ifcfg-eth0 DEVICE=e... ]]></description>
			<content:encoded><![CDATA[<p>高性能HP和高可用HA网络介面设定都是一样的<br />
cat /etc/sysconfig/network-scripts/ifcfg-bond0<br />
DEVICE=bond0<br />
IPADDR=192.168.10.104<br />
NETMASK=255.255.255.0<br />
ONBOOT=yes<br />
BOOTPROTO=none<br />
USERCTL=no</p>
<p>cat /etc/sysconfig/network-scripts/ifcfg-eth0<br />
DEVICE=eth0<br />
USERCTL=no<br />
ONBOOT=yes<br />
MASTER=bond0<br />
SLAVE=yes<br />
BOOTPROTO=none</p>
<p>cat /etc/sysconfig/network-scripts/ifcfg-eth1<br />
DEVICE=eth1<br />
USERCTL=no<br />
ONBOOT=yes<br />
MASTER=bond0<br />
SLAVE=yes<br />
BOOTPROTO=none</p>
<p>区别设定文件/etc/modprobe.conf中的mode的值<br />
mode的值表示工作模式，他共有0，1，2，3四种模式，常用的为0，1两种。需根据交换机可提供的工作模式选择。<br />
mode=0表示load balancing (round-robin)为负载均衡方式，两块网卡都工作。<br />
mode=1表示fault-tolerance (active-backup)提供冗余功能，工作方式是主备的工作方式，也就是说默认情况下只有一块网卡工作，另一块做备份。<br />
1.实现网络高性能HP则在/etc/modprobe.conf加入以下二行<br />
alias bond0 bonding<br />
options bond0 miimon=100 mode=0<br />
2.实现网络高可用HA则在/etc/modprobe.conf加入以下二行<br />
alias bond0 bonding<br />
options bond0 miimon=100 mode=1</p>
<p>设好配置文件后，执行如下二条指令即可，无需重启系统<br />
ldconfig<br />
/etc/init.d/network restart</p>
<p>查看 ifconfig -a<br />
bond0     Link encap:Ethernet  HWaddr 00:E0:4C:B1:0F:5A<br />
inet addr:192.168.10.104  Bcast:192.168.10.255  Mask:255.255.255.0<br />
UP BROADCAST RUNNING MASTER MULTICAST  MTU:1500  Metric:1<br />
RX packets:4805 errors:0 dropped:0 overruns:0 frame:0<br />
TX packets:2030 errors:0 dropped:0 overruns:0 carrier:0<br />
collisions:0 txqueuelen:0<br />
RX bytes:414775 (405.0 KiB)  TX bytes:420723 (410.8 KiB)</p>
<p>eth0      Link encap:Ethernet  HWaddr 00:E0:4C:B1:0F:5A<br />
UP BROADCAST RUNNING SLAVE MULTICAST  MTU:1500  Metric:1<br />
RX packets:2105 errors:0 dropped:0 overruns:0 frame:0<br />
TX packets:1194 errors:0 dropped:0 overruns:0 carrier:0<br />
collisions:0 txqueuelen:1000<br />
RX bytes:182497 (178.2 KiB)  TX bytes:240559 (234.9 KiB)<br />
Interrupt:5 Base address:0×8000</p>
<p>eth1      Link encap:Ethernet  HWaddr 00:E0:4C:B1:0F:5A<br />
UP BROADCAST RUNNING SLAVE MULTICAST  MTU:1500  Metric:1<br />
RX packets:2706 errors:0 dropped:0 overruns:0 frame:0<br />
TX packets:848 errors:0 dropped:0 overruns:0 carrier:0<br />
collisions:0 txqueuelen:1000<br />
RX bytes:232638 (227.1 KiB)  TX bytes:182028 (177.7 KiB)<br />
Interrupt:9 Base address:0×6000</p>
<p>lo        Link encap:Local Loopback<br />
inet addr:127.0.0.1  Mask:255.0.0.0<br />
UP LOOPBACK RUNNING  MTU:16436  Metric:1<br />
RX packets:1078 errors:0 dropped:0 overruns:0 frame:0<br />
TX packets:1078 errors:0 dropped:0 overruns:0 carrier:0<br />
collisions:0 txqueuelen:0<br />
RX bytes:1487408 (1.4 MiB)  TX bytes:1487408 (1.4 MiB)</p>
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		</item>
		<item>
		<title>人体器官24小时工作表</title>
		<link>http://226617.cn/archives/455.htm</link>
		<comments>http://226617.cn/archives/455.htm#comments</comments>
		<pubDate>Sat, 07 Mar 2009 14:22:04 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[只谈心情]]></category>
		<category><![CDATA[健康]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=455</guid>
		<description><![CDATA[身体是革命的本钱，熬夜不要熬太久 　　1∶00 人体进入浅睡阶段，易醒。此时头脑较清楚，熬夜者想睡反而睡不着。 　　2∶00 绝大多数器官处于一天中工作最慢的状态，肝脏却在紧张工作，... ]]></description>
			<content:encoded><![CDATA[<p>身体是革命的本钱，熬夜不要熬太久</p>
<p>　　1∶00 人体进入浅睡阶段，易醒。此时头脑较清楚，熬夜者想睡反而睡不着。</p>
<p>　　2∶00 绝大多数器官处于一天中工作最慢的状态，肝脏却在紧张工作，生血气为人体排毒。</p>
<p>　　3∶00 进入深度睡眠阶段，肌肉完全放松。</p>
<p>　　4∶00 “黎明前的黑暗”时刻，老年人最易发生意外。血压处于一天中最低值，糖尿病病人易出现低血糖，心脑血管患者易发生心梗等。</p>
<p>　　5∶00 阳气逐渐升华，精神状态饱满。</p>
<p>　　6∶00 血压开始升高，心跳逐渐加快。高血压患者得吃降压药了。</p>
<p>　　7∶00 人体免疫力最强。吃完早饭，营养逐渐被人体吸收。</p>
<p>　　8∶00 各项生理激素分泌旺盛，开始进入工作状态。</p>
<p>　　9∶00 适合打针、手术、做体检等。此时人体气血活跃，大脑皮层兴奋，痛感降低。</p>
<p>　　10∶00 工作效率最高。10∶00-11∶00属于人体的第一个黄金时段。心脏充分发挥其功能，精力充沛，不会感到疲劳。</p>
<p>　　12∶00 紧张工作一上午后，需要休息。12∶00-13∶00是最佳”子午觉”时间。不宜疲劳作战，最好躺着休息半小时至一小时。</p>
<p>　　14∶00 反应迟钝。易有昏昏欲睡之感，人体应激能力降低。</p>
<p>　　15∶00 午饭营养吸收后逐渐被输送到全身，工作能力开始恢复。15∶00-17∶00为人体第二个黄金时段。最适宜开会、公关、接待重要客人。</p>
<p>　　16∶00 血糖开始升高，有虚火者此时表现明显。阳虚、肺结核等患者的脸部最红。</p>
<p>　　17∶00 工作效率达到午后时间的最高值，也适宜进行体育锻炼。</p>
<p>　　18∶00 人体敏感度下降，痛觉随之再度降低。</p>
<p>　　19∶00 最易发生争吵。此时是人体血压波动的晚高峰，人们的情绪最不稳定。</p>
<p>　　20∶00 人体进入第三个黄金阶段。记忆力最强，大脑反应异常迅速。20∶00-21∶00适合做作业、阅读、创作、锻炼等。</p>
<p>　　22∶00 适合梳洗。呼吸开始减慢，体温逐渐下降。最好在十点半泡脚后上床，能很快入睡。</p>
<p>　　23∶00 阳气微弱，人体功能下降，开始逐渐进入深度睡眠，一天的疲劳开始缓解。</p>
<p>　　24∶00 气血处于一天中的最低值，除了休息，不宜进行任何活动。</p>
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		<item>
		<title>vmware workstation 非正常关机后无法打开虚拟机的问题解决</title>
		<link>http://226617.cn/archives/453.htm</link>
		<comments>http://226617.cn/archives/453.htm#comments</comments>
		<pubDate>Sat, 07 Mar 2009 13:11:28 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[vmware相关]]></category>
		<category><![CDATA[vmware]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=453</guid>
		<description><![CDATA[运行着vm的时候如果host忽然关机或者重启的话，再打开虚拟机会提示 the virtual machine is in use by an application on your host computer 解决方法进入虚拟机目录删除.lck文件和目... ]]></description>
			<content:encoded><![CDATA[<p>运行着vm的时候如果host忽然关机或者重启的话，再打开虚拟机会提示<br />
the virtual machine is in use by an application on your host computer<br />
解决方法进入虚拟机目录删除.lck文件和目录</p>
]]></content:encoded>
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		</item>
		<item>
		<title>linux下面启动network，startup eth0假死[没解决]</title>
		<link>http://226617.cn/archives/451.htm</link>
		<comments>http://226617.cn/archives/451.htm#comments</comments>
		<pubDate>Thu, 05 Mar 2009 01:30:57 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[linux相关]]></category>
		<category><![CDATA[eth0]]></category>
		<category><![CDATA[linux]]></category>
		<category><![CDATA[网络]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=451</guid>
		<description><![CDATA[昨天帮忙去给看了一台无法启动的linux主机，电话里说是启动网卡的时候显示eth0 什么错误之类的。 到哪里一看，是台联想万全的服务器，发现是启动到startup eth0提示ifcfg-eth0第x行:wq语法错误，... ]]></description>
			<content:encoded><![CDATA[<p>昨天帮忙去给看了一台无法启动的linux主机，电话里说是启动网卡的时候显示eth0 什么错误之类的。<br />
到哪里一看，是台联想万全的服务器，发现是启动到startup eth0提示ifcfg-eth0第x行:wq语法错误，然后就不动了，只能重启用逐个启动跳过了network进系统一看原来在ifcfg-eth0编辑退出的时候把:wq给写在里面了，汗。。。一直没重启所以没出问题。<br />
改完重启，仍然发现在启动到startup eth0卡死，然后继续跳过network进系统手工启动发现eth0启动后显示出一堆类似网卡工作参数的内容后就没反应了。这时候切换到tty2测试网络没问题。说明网络已经工作正常了，只是启动的脚本假死。ps了一下发现最后有个awk的进程，感觉应该和网卡启动脚本有关，于是kill几次后tty1里面启动脚本显示ok了。在restart一下没问题，但是在尝试重启的时候还是这样，后来时间也晚了，也没地方查资料，感觉好像是awk的问题，所以把network改成了手动启动，放到了rc.local最后面，这样启动卡死至少所有服务和网络都正常了，能够远程ssh连上去操作和重启。</p>
<p>这问题蛮奇怪的，因为说之前是正常的，我看看网卡似乎也是用的内核自带的驱动，莫非问题出在awk上面？</p>
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		<item>
		<title>Windows Vista常见问题及解决技巧</title>
		<link>http://226617.cn/archives/445.htm</link>
		<comments>http://226617.cn/archives/445.htm#comments</comments>
		<pubDate>Mon, 02 Mar 2009 01:18:24 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[windows相关]]></category>
		<category><![CDATA[vista]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=445</guid>
		<description><![CDATA[1.如何关闭UAC？ 控制面板→用户帐户→打开或关闭用户账户控制→取消使用用户账户控制（UAC）帮助保护您的计算机。 2.如何关闭系统备份与还原？ 控制面板→备份和还原中心→创建还原点或... ]]></description>
			<content:encoded><![CDATA[<p><strong>1.如何关闭UAC？</strong><br />
控制面板→用户帐户→打开或关闭用户账户控制→取消使用用户账户控制（UAC）帮助保护您的计算机。</p>
<p><strong>2.如何关闭系统备份与还原？</strong><br />
控制面板→备份和还原中心→创建还原点或更该设置→系统保护→自动还原点→取消已经选中的磁盘上的还原点。</p>
<p><strong>3.为什么在某个固定的时间会出现狂读硬盘的现象？<br />
</strong>这是因为Vista自动执行磁盘碎片整理计划的缘故，关闭的方法是通过开始菜单→附件→系统工具→磁盘碎片整理程序→取消“按计划运行（推荐）”</p>
<p><strong>4.如何关闭计算机进入休眠状态？</strong><br />
桌面右键→个性化→屏幕保护程序→更改电源设置→更改计算机的睡眠时间→使计算机进入睡眠状态设为从不。</p>
<p><strong>5.开始菜单电源按钮默认设定为“休眠”，如何更改为“关机”？</strong><br />
控制面版→电源选项→选中的“首选计划”→更改计划设置→更改高级电源设置，在弹出的设置窗口中找到“电源按钮和盖子”→“开始”菜单电源按钮→设置→关机，确定即可完成设置。</p>
<p><strong>6.每次开机时在安全中心都会提示，如何关闭这个提示信息？</strong><br />
控制面板→安全中心→更改安全中心通知我的方法→选择不通知我，但显示图标。</p>
<p><strong>7.如何在非传统开始菜单中显示运行命令？<br />
</strong>任务栏和开始菜单属性→开始菜单→自定义→选中“运行命令”。</p>
<p><strong>8.如何取消每次开机的默认共享？</strong><br />
使用Vista优化大师，或者将下列内容导入注册表，重启即可(前提是要关闭UAC)。<br />
Windows Registry Editor Version 5.00<br />
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Lanmanserver\Parameters]<br />
AutoShareWks=dword:00000000<br />
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Lsa]<br />
restrictanonymous=dword:00000001</p>
<p><strong>9.如何实现自动登陆？</strong><br />
开始→运行→输入“rundll32 netplwiz.dll,UsersRunDll”命令打开帐户窗口，先选中要自动登陆的账户，去选“要使用本机，用户必须输入用户名密码”复选框，输入该帐户的 密码即可(前提是要关闭UAC),，使用Vista之家出品的Vista优化大师更简单实现。</p>
<p><strong>10.如何更改媒体文件使用WMP以外的播放器播放？</strong><br />
选中媒体文件→右键菜单→打开方式→选择默认程序→选择播放程序→选中“始终使用选择的程序打开这种文件”。</p>
<p><strong>11.为何我无法实现局域网互访？</strong><br />
从以下几个方面入手：<br />
本地连接→右键属性→取消Internet协议版本6，缩短验证时间。<br />
检查机器工作组名称是否一致。<br />
检查机器IP是否在同一网段，如192.168.1.X。<br />
将网络和共享中心→网络连接→自定义→位置类型设置为专用，降低保护。</p>
<p><strong>12.开启ICF后局域网内机器如何实现互访？<br />
</strong>Windows防火墙取消阻止所有传入连接，并在“例外”中选中“文件和打印机共享”。</p>
<p><strong>13.如何实现用管理员(Administrator) 账户登陆？</strong><br />
计算机→管理→本地用户和组→用户→Administrator账户→属性→取消账户已禁用选项，当前使用账户→属性→选中账户已禁用选项。</p>
<p><strong>14.打开控制面板报错“Windows资源管理器已经停止工作”，要如何修复？</strong><br />
硬件驱动冲突，可能和声卡驱动有关，尝试重新安装声卡驱动。</p>
<p><strong>15.如何快速复制文件、文件夹路径？</strong><br />
按 Shift 键，右键需要复制路径的文件、文件夹或快捷方式等，在弹出菜单里面有一项复制为路径(A)，点击后可复制该文件、文件夹路径。</p>
<p><strong>16.如何察看系统许可信息？<br />
</strong>运行slmgr.vbs -dlv。</p>
<p><strong>17.文件反向选择的快捷键是什么？</strong><br />
ALT＋E弹出菜单后按I。</p>
<p><strong>18.如何更改桌面上的图标的大小？</strong><br />
Ctrl＋鼠标滚轮或者桌面右键→查看→经典图标。</p>
<p><strong>19.如何使用3D方式切换程序？<br />
</strong>在开启Aero外观的情况下，使用Win（视窗键）＋Tab可以使用3D方式切换程序，Win（视窗键）＋Ctrl＋Tab可以使程序3D窗口暂时停留在桌面上。</p>
<p><strong>20.如何设置IE浏览器代理？</strong><br />
打开IE工具栏的Internet选项→连接→拨号和虚拟专用网络设置中选中您的拨号连接→设置，在“设置 ”页面中，选中“对此连接使用代理服务器”然后在“地址”栏中填上代理服务器地址和端口，单击“确定”。</p>
<p><strong>21.如何查看某个进程的PID值？</strong><br />
任务管理器→查看→选择列中可以进行选择。</p>
<p><strong>22.如何实现退出系统时清除最近打开的文档的历史？</strong><br />
运行gpedit.msc，用户配置→管理模板→『开始』菜单和任务栏→退出系统时清除最近打开文档的历史，设为已启用就可以了。</p>
<p><strong>23.截图花屏</strong><br />
很多时候你会发现，Vista本身显示没问题，但无论是用Print Screen键，还是其他截图工具，所得的图中会有一部分花屏，有时是一条，有时是一块。这主要是Vista自带的显卡驱动程序不完善所造成的，解决方法是下载并安装最新版的显卡驱动，一般都能迎刃而解。</p>
<p><strong>24.找回消失的“运行”对话框</strong><br />
在默认情况下，Vista的开始菜单的底部是没有那个熟悉的“运行”命令的，这会给某些较高级的操作带来不便。我们可以通过下面的两种办法来调出“运行”对话框。<br />
(1) 通过“Win+R”组合键，即可打开“运行”对话框，这一招我们在第四个问题里已经用过。<br />
(2) 在开始菜单上点右键，选“属性”，进入开始菜单属性设置界面，单击底部的“自定义”按钮，在下面的列表框中找到“显示运行”并勾选，然后点“确认”退出，即可发现“运行”命令又重新出现在开始菜单的底部了。</p>
<p><strong>25.无法引导</strong><br />
无法引导是比较常见也比较严重的故障，以前在XP下，这种故障都是需要用户手动修复的。而在Vista下，你只需要通过光盘启动机器进入故障恢复控制台，然后输入fixboot命令，Vista便会自动检测启动故障，并自动利用BCDMD命令进行修复。这对普通用户是极大的帮助，值得称道。</p>
<p><strong>26.Vista下为什么QQ总是掉线？</strong><br />
Vista下QQ总是掉线，但是很快又恢复正常，这是由于 Vista 下网卡默认是工作在节能模式下的，若是您想让它继续节能，可以不用理会这个现象，因为他并不影响QQ的正常使用，若是需要处理，直接在设备管理器 →网络适配器→属性→电源管理中去掉“允许计算机关闭此设备以节约电源”前的勾即可！</p>
<p><strong>27.我在自动更新的时候为什么自动退出了？<br />
</strong>在自动更新过程中，自动更新需要下载并安装最新的升级程序，这个过程自动更新会关闭并重新启动，只要稍等片刻就会恢复正常。</p>
<p><strong>28.如何关闭休眠功能？<br />
</strong>开始－运行－powercfg -h off</p>
]]></content:encoded>
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		</item>
		<item>
		<title>如何修改xp登录时的桌面背景</title>
		<link>http://226617.cn/archives/443.htm</link>
		<comments>http://226617.cn/archives/443.htm#comments</comments>
		<pubDate>Mon, 02 Mar 2009 01:16:58 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[windows相关]]></category>
		<category><![CDATA[xp]]></category>
		<category><![CDATA[背景]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=443</guid>
		<description><![CDATA[我电脑最近忽然在登录的时候出现了桌面背景图片，奇怪的是我从来没有设置过背景图片。网上搜了搜，用注册表编辑器找到HKEY_USERS\.DEFAULT\Control Panel\Desktop子键分支，把Wallpaper清空，再把Wallpa... ]]></description>
			<content:encoded><![CDATA[<p>我电脑最近忽然在登录的时候出现了桌面背景图片，奇怪的是我从来没有设置过背景图片。网上搜了搜，用注册表编辑器找到HKEY_USERS\.DEFAULT\Control Panel\Desktop子键分支，把Wallpaper清空，再把Wallpaper内容路径的图片删除就搞定了。</p>
]]></content:encoded>
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		</item>
		<item>
		<title>关于mysql的字符集架构</title>
		<link>http://226617.cn/archives/441.htm</link>
		<comments>http://226617.cn/archives/441.htm#comments</comments>
		<pubDate>Tue, 24 Feb 2009 01:11:07 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[mysql相关]]></category>
		<category><![CDATA[mysql]]></category>
		<category><![CDATA[字符集]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=441</guid>
		<description><![CDATA[看了http://item.feedsky.com/~feedsky/phpv/~1232318/176981487/1235221/1/item.html 的这篇文章，整理了下觉得这些对我很有帮助，记录一下 MySQL的字符集处理是这样的： 1）发送请求 客户端(character_set_client）=》... ]]></description>
			<content:encoded><![CDATA[<p>看了http://item.feedsky.com/~feedsky/phpv/~1232318/176981487/1235221/1/item.html<br />
的这篇文章，整理了下觉得这些对我很有帮助，记录一下 </p>
<p>MySQL的字符集处理是这样的：</p>
<p>1）发送请求<br />
客户端(character_set_client）=》数据库连接(character_set_connection)=》存储(table,column)<br />
2）返回请求<br />
存储(table,column)=》数据库连接(character_set_connection )=》客户端(character_set_results)</p>
<p>在每一个非初始节点，都会做一次从上一个结点到当前节点的字符集转换操作。举个例子，有如下环境：<br />
* character_set_connection utf-8<br />
* character_set_results gbk<br />
* character_set_client gb2312<br />
* 有表A，字段字符集全部为BIG5</p>
<p>发送请求的时候，首先数据从gbk转换为utf-8，再转换为BIG5，然后再存储。<br />
返回请求的时候，首先数据从BIG5转换为utf-8，再转换为gb2312，然后再发送给客户端。</p>
<p>如果完全不需要对数据进行排序，like或者全文检索，那么请停止使用char，varchar，text之类的吧。 binary，varbinary，BLOB才是正确的选择。binary之类的在存储，取出的时候都不会进行字符集转换，而在排序时候，只根据二进制内 容排序，所以在效率上高出char，varchar，text很多</p>
<p>另外提一下PHP里的设置字符集。大家请不要再使用mysql_query(”set names utf8″)这样的语句了。mysql_set_charset()才 是最完整的字符集设置方式。后者比前者多一个设置，就是把struct MySQL的charset成员也设置了。这个成员变量在escape的时候起着很重要的作用，特别是对于GBK这种运行把“\”作为字符一部分的编码格式。如果你只使用mysql_query(”set names XXX”)，那么在某些字符集，会有重大的安全漏洞，导致mysql_real_escape_string变得和addslashes一样不安全。</p>
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		<item>
		<title>php动态方式加载gd编译方法</title>
		<link>http://226617.cn/archives/428.htm</link>
		<comments>http://226617.cn/archives/428.htm#comments</comments>
		<pubDate>Wed, 18 Feb 2009 15:58:11 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[linux相关]]></category>
		<category><![CDATA[php相关]]></category>
		<category><![CDATA[gd]]></category>
		<category><![CDATA[php]]></category>
		<category><![CDATA[动态加载]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=428</guid>
		<description><![CDATA[首先安装好gd 假设gd是安装在/usr/local/gd2，php是安装在/usr/local/php-cgi的话 cd /usr/local/src/php-5.2.8/ext/gd/ /usr/local/php-cgi/bin/phpize ./configure &#8211;with-gd=/usr/local/gd2 &#8211;with-php-config=/usr/local/php-cgi/bin/php-c... ]]></description>
			<content:encoded><![CDATA[<p>首先安装好gd<br />
假设gd是安装在/usr/local/gd2，php是安装在/usr/local/php-cgi的话</p>
<p>cd /usr/local/src/php-5.2.8/ext/gd/<br />
/usr/local/php-cgi/bin/phpize<br />
./configure &#8211;with-gd=/usr/local/gd2 &#8211;with-php-config=/usr/local/php-cgi/bin/php-config<br />
make &#038;&#038; make install</p>
<p>然后再修改php.ini文件<br />
　　手工修改：查找/usr/local/php-cgi/etc/php.ini中的extension_dir = &#8220;./&#8221;<br />
　　修改为extension_dir = &#8220;/usr/local/php-cgi/lib/php/extensions/no-debug-non-zts-20060613/&#8221;<br />
　　并在此行后增加以下几行，然后保存：<br />
　　extension = &#8220;gd2.so&#8221;</p>
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		</item>
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		<title>x64位系统下php iconv函数输出空白问题</title>
		<link>http://226617.cn/archives/425.htm</link>
		<comments>http://226617.cn/archives/425.htm#comments</comments>
		<pubDate>Wed, 18 Feb 2009 15:47:00 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[linux相关]]></category>
		<category><![CDATA[php相关]]></category>
		<category><![CDATA[iconv]]></category>
		<category><![CDATA[php]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=425</guid>
		<description><![CDATA[接着昨天那个iconv问题继续研究，发现iconv函数数据输出为空。经过分析基本判断为gd库和iconv的冲突问题只要php编译中加入gd库支持就会导致这一情况，但是在x86系统里面缺完全没有这个问题，... ]]></description>
			<content:encoded><![CDATA[<p>接着昨天那个iconv问题继续研究，发现iconv函数数据输出为空。经过分析基本判断为gd库和iconv的冲突问题只要php编译中加入gd库支持就会导致这一情况，但是在x86系统里面缺完全没有这个问题，看来只是x64的问题。解决方法是把gd或者iconv作为作为动态模块加载，总之避免gd和iconv同时使用静态方式编译就行。ps：后来我发现我有一台x64的机器都是静态编译的但是就偏偏没有这个问题真是奇怪了。看来这问题还是有一定前提的</p>
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		</item>
		<item>
		<title>discuz论坛wap浏览无中文解决方法</title>
		<link>http://226617.cn/archives/422.htm</link>
		<comments>http://226617.cn/archives/422.htm#comments</comments>
		<pubDate>Tue, 17 Feb 2009 15:31:18 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[php相关]]></category>
		<category><![CDATA[软件相关]]></category>
		<category><![CDATA[discuz]]></category>
		<category><![CDATA[wap]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=422</guid>
		<description><![CDATA[一个兄弟网站的discuz论坛换了台新的服务器，从apache换到了nginx结果发现换了之后wap访问论坛出来的页面没有任何中文字（英文还是存在的）。我在看了之后一开始以为是wap程序php取数据库编码... ]]></description>
			<content:encoded><![CDATA[<p>一个兄弟网站的discuz论坛换了台新的服务器，从apache换到了nginx结果发现换了之后wap访问论坛出来的页面没有任何中文字（英文还是存在的）。我在看了之后一开始以为是wap程序php取数据库编码的问题。后来做了几次修改尝试后发现并非数据库输出内容无中文，而且经过和我们的对比发现连普通的静态内容的中文也都是没有的，一下子就想到问题出在了php上面，于是安装wap下面原来的index.php输出方式手写了一个临时php调试，发现php输出都没问题，有乱码出现，看来问题出在编码转换上面。于是自己看了下discuz的编码转码的库文件chinese.class.php，发现这台新服务器是启用iconv函数的，里面检测到了iconv然后使用iconv函数进行编码转换，忽然想到可能是系统iconv函数库的问题。于是找的了判断iconv的代码：</p>

<div class="wp_syntax"><table><tr><td class="line_numbers"><pre>1
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</pre></td><td class="code"><pre class="php" style="font-family:monospace;"><span style="color: #b1b100;">if</span><span style="color: #009900;">&#40;</span><span style="color: #990000;">function_exists</span><span style="color: #009900;">&#40;</span><span style="color: #0000ff;">'iconv'</span><span style="color: #009900;">&#41;</span> <span style="color: #339933;">&amp;&amp;</span> <span style="color: #000088;">$this</span><span style="color: #339933;">-&gt;</span><span style="color: #004000;">config</span><span style="color: #009900;">&#91;</span><span style="color: #0000ff;">'TargetLang'</span><span style="color: #009900;">&#93;</span> <span style="color: #339933;">!=</span> <span style="color: #0000ff;">'BIG5'</span> <span style="color: #339933;">&amp;&amp;</span> <span style="color: #339933;">!</span><span style="color: #000088;">$ForceTable</span><span style="color: #009900;">&#41;</span> <span style="color: #009900;">&#123;</span>
   <span style="color: #000088;">$this</span><span style="color: #339933;">-&gt;</span><span style="color: #004000;">iconv_enabled</span> <span style="color: #339933;">=</span> <span style="color: #009900; font-weight: bold;">true</span><span style="color: #339933;">;</span>
<span style="color: #009900;">&#125;</span> <span style="color: #b1b100;">else</span> <span style="color: #009900;">&#123;</span>
   <span style="color: #000088;">$this</span><span style="color: #339933;">-&gt;</span><span style="color: #004000;">iconv_enabled</span> <span style="color: #339933;">=</span> <span style="color: #009900; font-weight: bold;">false</span><span style="color: #339933;">;</span>
   <span style="color: #000088;">$this</span><span style="color: #339933;">-&gt;</span><span style="color: #004000;">OpenTable</span><span style="color: #009900;">&#40;</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">;</span>
<span style="color: #009900;">&#125;</span>
<span style="color: #339933;">......</span></pre></td></tr></table></div>

<p>修改了这段代码绕过了iconv检测，强制设为不存在iconv的方式处理编码转换。</p>

<div class="wp_syntax"><table><tr><td class="line_numbers"><pre>1
2
</pre></td><td class="code"><pre class="php" style="font-family:monospace;">   <span style="color: #000088;">$this</span><span style="color: #339933;">-&gt;</span><span style="color: #004000;">iconv_enabled</span> <span style="color: #339933;">=</span> <span style="color: #009900; font-weight: bold;">false</span><span style="color: #339933;">;</span>
   <span style="color: #000088;">$this</span><span style="color: #339933;">-&gt;</span><span style="color: #004000;">OpenTable</span><span style="color: #009900;">&#40;</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">;</span></pre></td></tr></table></div>

<p>然后测试果然中文又回来了。</p>
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		<title>PsTools系统命令行增强工具命令参数详解</title>
		<link>http://226617.cn/archives/416.htm</link>
		<comments>http://226617.cn/archives/416.htm#comments</comments>
		<pubDate>Thu, 05 Feb 2009 14:11:14 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[windows相关]]></category>
		<category><![CDATA[软件相关]]></category>
		<category><![CDATA[PsTools]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=416</guid>
		<description><![CDATA[PsTools是微软收购的Sysinternals小组的一个命令行的win系统命令行管理工具目前最新版本是2.44 下载pstools，由于某些原因无法进行图形远程管理服务器的时候，PsTools就能大显身手了。 PsTools 套件中... ]]></description>
			<content:encoded><![CDATA[<p>PsTools是微软收购的Sysinternals小组的一个命令行的win系统命令行管理工具目前最新版本是2.44 <a href='http://226617.cn/wp-content/uploads/2009/02/pstools.zip'>下载pstools</a>，由于某些原因无法进行图形远程管理服务器的时候，PsTools就能大显身手了。</p>
<p>PsTools 套件中包含以下工具：<br />
PsExec &#8211; 远程执行进程<br />
PsFile &#8211; 显示远程打开的文件<br />
PsGetSid &#8211; 显示计算机或用户的 SID<br />
PsInfo &#8211; 列出有关系统的信息<br />
PsKill &#8211; 按名称或进程 ID 终止进程<br />
PsList &#8211; 列出有关进程的详细信息<br />
PsLoggedOn &#8211; 查看在本地通过资源共享（包含所有资源）登录的用户<br />
PsLogList &#8211; 转储事件日志记录<br />
PsPasswd － 更改帐户密码<br />
PsService &#8211; 查看和控制服务<br />
PsShutdown &#8211; 关闭并重新启动（可选）计算机<br />
PsSuspend &#8211; 暂停进程<br />
PsUptime &#8211; 向您显示系统自上次重新启动以来的运行时间（PsUptime 的功能已集成到 PsInfo 中）</p>
<p>使用方法:<br />
将所有工具复制到windows目录下CMD命令界面键入工具名称,然后输入命令行参数即可。不想复制到windows目录的朋友，就要<br />
键入工具所在的完整的路径,然后输入命令行参数。要显示完整的用法信息，请指定“-”命令行选项。</p>
<p>工具命令参数详解：</p>
<p>1、psexec<br />
psexec是一个远程执行工具，你可以像使用telnet一样使用它。</p>
<p>它的使用格式为：</p>
<p>psexec \远程机器ip [-u username [-p password]] [-c [-f]] [-i][-d] program [arguments]<br />
它的参数有：<br />
-u后面跟用户名 -p后面是跟密码的,如果建立ipc连接后这两个参数则不需要。（如果没有-p参数，则输入命令后会要求你输入密码）<br />
-c &lt; [路径]文件名&gt;:拷贝文件到远程机器并运行（注意：运行结束后文件会自动删除）<br />
-d 不等待程序执行完就返回，（比如要让远程机器运行tftp服务端的时候使用，不然psexec命令会一直等待tftp程序结束才会返回）<br />
-i 在远程机器上运行一个名为psexesvc进程，(到底什么用弄不明白）<br />
假设我在远程机器ip有一个账号，账号名是：abc 密码是：123<br />
比如想要用telnet一样在远程系统上执行命令可以打：<br />
psexec \远程机器ip -u abc -p 123 cmd<br />
如果想要远程机器执行本地c:srm.exe文件可以打：<br />
psexec \远程机器ip -u abc -p 123 -c c:srm.exe<br />
如果想要让远程机器执行本地上tftp服务端，(假设tftp服务端在本地c:tftp32.exe)，可以打：<br />
psexec \远程机器ip -u abc -p 123 -c c:tftp32.exe -d<br />
（后面例子不再重复-u和-p的用法）</p>
<p>2、psservice<br />
psservice是一个服务管理程序。</p>
<p>它的使用格式为：</p>
<p>psservice [\远程机器ip [-u username] [-p password]]<br />
它的参数只有：<br />
-u 后面跟用户名 -p后面是跟密码的,如果建立ipc连接后这两个参数则不需要。（如果没有-p参数，则输入命令后会要求你输入密码）<br />
它的command有：<br />
query [服务名]:显示某一服务的状态，如不填服务名则显示所有服务的状态。<br />
config &lt; 服务名&gt;：显示某一服务的配置。<br />
start &lt; 服务名&gt;：启动某一服务。<br />
stop &lt; 服务名&gt;：停止某一服务。<br />
testart &lt; 服务名&gt;：停止某一服务并重新启动它。<br />
pause &lt; 服务名&gt;：暂停某一服务。<br />
cont &lt; 服务名&gt;：恢复暂停的服务。<br />
depend &lt; 服务名&gt;：显示某一服务依存关系。<br />
find &lt; 服务名&gt;：在网络种搜寻指定的服务。<br />
比如你想查看在远程机器上的telnet服务的状态可以打：<br />
psservice \远程机器ip query tlntsvr （tlntsvr为telnet服务的服务名）<br />
比如你查看远程机器上的telnet服务的配置可以打：<br />
psservice \远程机器ip config tlntsvr<br />
比如你想启动远程机器上的telnet服务可以打：<br />
psservice \远程机器ip start tlntsvr<br />
其他用法以此类推。</p>
<p>3、pssuspend<br />
pssuspend是一个暂时停止进程的软件</p>
<p>它的使用格式为：</p>
<p>pssuspend [-r] [\远程机器ip [-u username] [-p password]]<br />
它有三个参数：<br />
-u：后面跟用户名 -p：后面是跟密码的,如果建立ipc连接后这两个参数则不需要。（如果没有-p参数，则输入命令后会要求你输入密码）<br />
-r:恢复进程。<br />
比如要暂时停止一个pid号为999,名称为srm.exe的进程可以打：<br />
pssuspend \远程机器ip 999 或 pssuspend \远程机器ip srm<br />
如果想要恢复它就可以打pssuspend -r \远程机器ip 999 或 pssuspend -r \远程机器ip srm</p>
<p>4、psinfo<br />
psinfo是一个搜集机器软硬件信息的工具，它可以获得操作系统信息，硬件信息和软件信息。</p>
<p>它的使用格式为：</p>
<p>psinfo [-h] [-s] [-d] [-c] [\远程机器ip [-u username [-p password]]]<br />
它的参数有：<br />
-u：后面跟用户名 -p：后面是跟密码的,如果建立ipc连接后这两个参数则不需要。（如果没有-p参数，则输入命令后会要求你输入密码）<br />
-h：是显示它安装了哪些补丁包<br />
-s：是显示它装了哪些软件<br />
-d：是显示磁盘信息。<br />
比如我只想看远程机器的软硬件信息和只用打:<br />
psinfo \远程机器ip<br />
假如我还想看看它装了哪些补丁包可以打<br />
psinfo -h \远程机器ip<br />
假如我还想看看它磁盘信息可以打：<br />
psinfo -d \远程机器ip<br />
如果我想看它装了哪些软件可以打：<br />
psinfo -s \远程机器ip<br />
简单吧.</p>
<p>5、pslist<br />
pslist是一个查看进程的程序。</p>
<p>它的使用格式为：</p>
<p>pslist [-d] [-m] [-x][-t][-s [n] [-r n] [\远程机器ip [-u username] [-p password]] [name | pid]<br />
它的参数有：<br />
-u：后面跟用户名 -p：后面是跟密码的,如果建立ipc连接后这两个参数则不需要。（如果没有-p参数，则输入命令后会要求你输入密码）<br />
-s：是使用任务管理器模式实时查看进程，可以按ESC键退出。<br />
-r &lt; 秒数&gt;：是和-s连用的一个参数，它用来指定任务管理器模式是的刷新间隔。（默认的刷新间隔为1秒）<br />
-d：示各个进程的cpu使用信息。<br />
-m：显示各个进程的存储器使用信息。<br />
-x：非常详细显示进程的所有信息。<br />
-t：以树型方式显示进程。<br />
比如要查看远程机器ip上的进程的cpu使用信息可以打:<br />
pslist -d \远程机器ip<br />
比如要查看一个pid号为999,名称为srm.exe进程的存储器使用信息可以打：<br />
pslist -m \远程机器ip 999 或 pslist -m \远程机器ip srm<br />
比如要以任务管理器模式实时查看61.12.23.4上进程情况，并且刷新间隔为3秒可以打：<br />
pslist -s -n 3 \远程机器ip</p>
<p>6、psuptime<br />
psuptime是一个了解远程机器运行了多久的命令。</p>
<p>使用它只需要打：psuptime \远程机器ip</p>
<p>7、psshutdown<br />
psshutdown是一个远程关机命令。</p>
<p>它的使用格式为：</p>
<p>psshutdown [[-s | -r | -k [-t nn][-m "消息"][-f]] -a | -l | -o] [\远程机器ip]<br />
它的参数有：<br />
-a：取消以前执行的关机指令。<br />
-t：离关机还有多少秒。（默认是20秒）<br />
-s：关闭机器。<br />
-m：是要显示的信息。<br />
-f：是关机是不保存运行的程序。<br />
-r：表示重启。<br />
-l：表示锁定电脑。<br />
-o：表示注销用户。<br />
比如我想让远程机器30秒后关闭并显示(要关机了，请保存文件)则打：<br />
psshutdown -t 30 -s -m &#8220;要关机了，请保存文件&#8221; \远程机器ip<br />
如果是要重起的话打：<br />
psshutdown -t 30 -m &#8220;要关机了，请保存文件&#8221; -r \远程机器ip<br />
如果要取消刚才的指令可以打：<br />
psshutdown -a \远程机器ip<br />
其他参数以此类推。</p>
<p>8、psfile<br />
psfile是一个显示机器上的会话和有什么文件被网络中的用户的打开的命令。</p>
<p>它的使用格式为：</p>
<p>psfile [\远程机器ip [-u Username [-p Password]]] [[Id | path] [-c]]<br />
它的参数有:<br />
-u 后面跟用户名 -p后面是跟密码的,如果建立ipc连接后这两个参数则不需要。（如果没有-p参数，则输入命令后会要求你输入密码）<br />
-c：关闭会话或文件<br />
比如我想看看远程机器上的会话和被远程用户打开的文件可以打：<br />
psfile \远程机器ip<br />
接着就会显示<br />
[33] C:WINNT<br />
User: ADMINISTRATOR<br />
Locks: 0<br />
Access: Read<br />
[63] PIPEsrvsvc<br />
User: ADMINISTRATOR<br />
Locks: 0<br />
Access: Read Write<br />
接着我想关闭id为33，路径为c:winnt的这个会话可以打<br />
psfile \远程机器ip 33 -c 或 psfile \远程机器ip c:winnt -c</p>
<p>9、psloggedon</p>
<p>psloggedon是一个显示目前谁登陆的机器的命令。</p>
<p>它的参数只有:</p>
<p>-l只显示本地登陆用户而不显示其它的网络登陆用户<br />
-x不显示登陆时间<br />
比如说要显示远程机器现在登陆的用户可以打：<br />
psloggedon \远程机器ip</p>
<p>10、psgetsid<br />
psgetsid是一个远程获取账号sid信息的工具。</p>
<p>它的使用格式为：</p>
<p>psgetsid [\远程机器ip [-u username [-p password]]] [account]<br />
它的参数有<br />
-u 后面跟用户名 -p后面是跟密码的,如果建立ipc连接后这两个参数则不需要。（如果没有-p参数，则输入命令后会要求你输入密码）<br />
比如要看远程机器上账号名为abc的sid信息可以打：<br />
psgetsid \远程机器ip abc</p>
<p>11、pskill</p>
<p>pskill是一个杀除进程的程序。<br />
它的使用格式为：</p>
<p>pskill [\远程机器ip [-u username] [-p password]] 比如要杀除一个pid号为999,名称为srm.exe的进程可以打：<br />
pskill \远程机器ip 999 或 pskill \远程机器ip srm</p>
<p>12、psloglist<br />
psloglist</p>
<p>psloglist是一个查看系统事件记录的程序。</p>
<p>它的使用格式为：<br />
psloglist [\远程机器ip [-u username [-p password]]] [-s [-t delimiter]] [-n # | -d #] [-c][-x][-r][-a mm/dd/yy][-b mm/dd/yy][-f filter] [-l event log file]<br />
它的参数有：<br />
-u 后面跟用户名 -p后面是跟密码的,如果建立ipc连接后这两个参数则不需要。<br />
-c:显示事件之后清理事件记录<br />
-l &lt; 事件记录文件名&gt;:用于查看事件记录文件<br />
-n ：只显示最近的n条系统事件记录。<br />
-d ：只显示n天以前的系统事件记录<br />
-a mm/dd/yy:显示mm/dd/yy以后的系统事件记录<br />
-b mm/dd/yy:显示mm/dd/yy以前的系统事件记录<br />
-f &lt; 事件类型&gt;：只显示指定的事件类型的系统事件记录。<br />
-x：显示事件数据代码<br />
-r：从旧到新排列（如不加则默认是从新到旧排列）<br />
-s:以一个事件为一行的格式显示，中间默认以逗号格开各个信息。<br />
-t &lt; 字符&gt;:这个参数和-s连用，以来改变-s中默认的逗号。<br />
如果我想看远程机器的系统事件记录只用打：<br />
psloglist \远程机器ip 123<br />
比如我想看最近的10条error类型的记录可以打：<br />
psloglist \远程机器ip -n 10 -f error</p>
<p>显示格式：</p>
<p>每个服务的属性按照以下格式显示。</p>
<p>&gt;服务名<br />
服务显示名<br />
[类型] [启动方式] [时间戳]<br />
服务程序全路径<br />
服务Dll全路径（共享进程的服务才有此项）</p>
<p>注：时间戳表示服务属性最后一次被改变的时间。用本程序改的除外。</p>
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		<title>nokia e50刷机升级中途弹出找到新硬件问题解决</title>
		<link>http://226617.cn/archives/414.htm</link>
		<comments>http://226617.cn/archives/414.htm#comments</comments>
		<pubDate>Mon, 19 Jan 2009 15:00:17 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[软件相关]]></category>
		<category><![CDATA[nokia]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=414</guid>
		<description><![CDATA[最近我的e50感觉速度越来越慢，所以想重装下顺便升级。网上下载了最新的PC Suite 7.1 和nsu准备升级，试了n边每次都是升级到开始更新一会就弹出找到新硬件然后就提示刷新失败。后来折腾来折... ]]></description>
			<content:encoded><![CDATA[<p>最近我的e50感觉速度越来越慢，所以想重装下顺便升级。网上下载了最新的PC Suite 7.1 和nsu准备升级，试了n边每次都是升级到开始更新一会就弹出找到新硬件然后就提示刷新失败。后来折腾来折腾去，数据线驱动给我搞坏了，目录也给我删了，于是又去单独下载了个数据线驱动也没细看搞完竟然刷机成功了。在仔细对比一看原来我新下载的单独的数据线驱动是6.83的。晕感情新的7.1的驱动反而到有问题了</p>
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		<item>
		<title>Cisco IOS HTTP Server多个跨站脚本漏洞</title>
		<link>http://226617.cn/archives/411.htm</link>
		<comments>http://226617.cn/archives/411.htm#comments</comments>
		<pubDate>Fri, 16 Jan 2009 15:46:29 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[硬件相关]]></category>
		<category><![CDATA[cisco]]></category>
		<category><![CDATA[漏洞]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=411</guid>
		<description><![CDATA[用cisco的当心了赶紧检查下吧 发布日期：2009-01-14 更新日期：2009-01-15 受影响系统： Cisco IOS 12.4 Cisco IOS 12.3 Cisco IOS 12.2 Cisco IOS 12.1 Cisco IOS 12.0 描述： &#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8... ]]></description>
			<content:encoded><![CDATA[<p>用cisco的当心了赶紧检查下吧</p>
<p>发布日期：2009-01-14<br />
更新日期：2009-01-15</p>
<p>受影响系统：<br />
Cisco IOS 12.4<br />
Cisco IOS 12.3<br />
Cisco IOS 12.2<br />
Cisco IOS 12.1<br />
Cisco IOS 12.0<br />
描述：<br />
&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8211;<br />
BUGTRAQ  ID: 33260<br />
CVE(CAN) ID: CVE-2008-3821</p>
<p>Cisco IOS是思科网络设备所使用的互联网操作系统。</p>
<p>如果Cisco IOS中启用了HTTP Server的话，攻击者就可以通过向服务器端二进制程序/脚本提交无效参数执行跨站脚本攻击。这类攻击可能导致替换目标管理界面，或将保密信息重新定向到非授权的第三方，例如，可以通过XMLHttpRequest对象修改/level/15/exec/-/show/run/CR URL所返回的数据。此外攻击者还可以通过跨站请求伪造攻击执行管理操作，例如注入指向/level/15/configure/-/enable/secret/newpass的img标签会将enable口令更改为newpass。</p>
<p>< *来源：Adrian Pastor （m123303@richmond.ac.uk）<br />
        Richard J. Brain</p>
<p>  链接：http://marc.info/?l=bugtraq&#038;m=123195734420830&#038;w=2</p>
<p>http://marc.info/?l=bugtraq&#038;m=123195579017761&#038;w=2</p>
<p>http://secunia.com/advisories/33461/</p>
<p>*></p>
<p>测试方法：<br />
&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8211;</p>
<p>警 告</p>
<p>以下程序(方法)可能带有攻击性，仅供安全研究与教学之用。使用者风险自负！</p>
<p>http://192.168.100.1/ping?<script>alert("Running+code+within+the_context+of+"%2bdocument.domain)</script></p>
<p>建议：<br />
&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8211;<br />
临时解决方法：</p>
<p>如果您不能立刻安装补丁或者升级，NSFOCUS建议您采取以下措施以降低威胁：</p>
<p>* 如果设备上无需HTTP server，以配置模式使用以下命令禁用：</p>
<p>    no ip http server<br />
    no ip http secure-server</p>
<p>* 如果需要HTTP server，控制可访问HTTP server的主机，对HTTP server应用访问控制列表：</p>
<p>    ip http access-class {access-list-number | access-list-name}</p>
<p>以下示例仅允许可信任的主机访问Cisco IOS HTTP server：</p>
<p>    ip access-list standard 20<br />
    permit 192.168.1.0 0.0.0.255<br />
    remark &#8220;Above is a trusted subnet&#8221;<br />
    remark &#8220;Add further trusted subnets or hosts below&#8221;</p>
<p>    ! (Note: all other access implicitly denied)<br />
    ! (Apply the access-list to the http server)</p>
<p>    ip http access-class 20</p>
<p>厂商补丁：</p>
<p>Cisco<br />
&#8212;&#8211;<br />
目前厂商还没有提供补丁或者升级程序，我们建议使用此软件的用户随时关注厂商的主页以获取最新版本：</p>
<p>http://www.cisco.com/warp/public/707/advisory.html</p>
]]></content:encoded>
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		</item>
		<item>
		<title>MySQL配置文件my.cnf中文版</title>
		<link>http://226617.cn/archives/409.htm</link>
		<comments>http://226617.cn/archives/409.htm#comments</comments>
		<pubDate>Fri, 16 Jan 2009 05:07:22 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[mysql相关]]></category>
		<category><![CDATA[mysql]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=409</guid>
		<description><![CDATA[从 hi!admin 抄来的一份配置.注释得非常好. #BEGIN CONFIG INFO #DESCR: 4GB RAM, 只使用InnoDB, ACID, 少量的连接, 队列负载大 #TYPE: SYSTEM #END CONFIG INFO # # 此mysql配置文件例子针对4G内存 # 主要使用INNODB #处理复... ]]></description>
			<content:encoded><![CDATA[<p>从 hi!admin 抄来的一份配置.注释得非常好.</p>
<p>#BEGIN CONFIG INFO<br />
#DESCR: 4GB RAM, 只使用InnoDB, ACID, 少量的连接, 队列负载大<br />
#TYPE: SYSTEM<br />
#END CONFIG INFO</p>
<p>#<br />
# 此mysql配置文件例子针对4G内存<br />
# 主要使用INNODB<br />
#处理复杂队列并且连接数量较少的mysql服务器<br />
#<br />
# 将此文件复制到/etc/my.cnf 作为全局设置,<br />
# mysql-data-dir/my.cnf 作为服务器指定设置<br />
# (@localstatedir@ for this installation) 或者放入<br />
# ~/.my.cnf 作为用户设置.<br />
#<br />
# 在此配置文件中, 你可以使用所有程序支持的长选项.<br />
# 如果想获悉程序支持的所有选项<br />
# 请在程序后加上&#8221;&#8211;help&#8221;参数运行程序.<br />
#<br />
# 关于独立选项更多的细节信息可以在手册内找到<br />
#</p>
<p>#<br />
# 以下选项会被MySQL客户端应用读取.<br />
# 注意只有MySQL附带的客户端应用程序保证可以读取这段内容.<br />
# 如果你想你自己的MySQL应用程序获取这些值<br />
# 需要在MySQL客户端库初始化的时候指定这些选项</p>
<p>#<br />
[client]<br />
#password	= [your_password]<br />
port	 = @MYSQL_TCP_PORT@<br />
socket	 = @MYSQL_UNIX_ADDR@</p>
<p># *** 应用定制选项 ***</p>
<p>#<br />
#  MySQL 服务端<br />
#<br />
[mysqld]</p>
<p># 一般配置选项<br />
port	 = @MYSQL_TCP_PORT@<br />
socket	 = @MYSQL_UNIX_ADDR@</p>
<p># back_log 是操作系统在监听队列中所能保持的连接数,<br />
# 队列保存了在MySQL连接管理器线程处理之前的连接.<br />
# 如果你有非常高的连接率并且出现&#8221;connection refused&#8221; 报错,<br />
# 你就应该增加此处的值.<br />
# 检查你的操作系统文档来获取这个变量的最大值.<br />
# 如果将back_log设定到比你操作系统限制更高的值,将会没有效果<br />
back_log = 50</p>
<p># 不在TCP/IP端口上进行监听.<br />
# 如果所有的进程都是在同一台服务器连接到本地的mysqld,<br />
# 这样设置将是增强安全的方法<br />
# 所有mysqld的连接都是通过Unix sockets 或者命名管道进行的.<br />
# 注意在windows下如果没有打开命名管道选项而只是用此项<br />
# (通过 &#8220;enable-named-pipe&#8221; 选项) 将会导致mysql服务没有任何作用!<br />
#skip-networking</p>
<p># MySQL 服务所允许的同时会话数的上限<br />
# 其中一个连接将被SUPER权限保留作为管理员登录.<br />
# 即便已经达到了连接数的上限.<br />
max_connections = 100</p>
<p># 每个客户端连接最大的错误允许数量,如果达到了此限制.<br />
# 这个客户端将会被MySQL服务阻止直到执行了&#8221;FLUSH HOSTS&#8221; 或者服务重启<br />
# 非法的密码以及其他在链接时的错误会增加此值.<br />
# 查看 &#8220;Aborted_connects&#8221; 状态来获取全局计数器.<br />
max_connect_errors = 10</p>
<p># 所有线程所打开表的数量.<br />
# 增加此值就增加了mysqld所需要的文件描述符的数量<br />
# 这样你需要确认在[mysqld_safe]中 &#8220;open-files-limit&#8221; 变量设置打开文件数量允许至少4096<br />
table_cache = 2048</p>
<p># 允许外部文件级别的锁. 打开文件锁会对性能造成负面影响<br />
# 所以只有在你在同样的文件上运行多个数据库实例时才使用此选项(注意仍会有其他约束!)<br />
# 或者你在文件层面上使用了其他一些软件依赖来锁定MyISAM表<br />
#external-locking</p>
<p># 服务所能处理的请求包的最大大小以及服务所能处理的最大的请求大小(当与大的BLOB字段一起工作时相当必要)<br />
# 每个连接独立的大小.大小动态增加<br />
max_allowed_packet = 16M</p>
<p># 在一个事务中binlog为了记录SQL状态所持有的cache大小<br />
# 如果你经常使用大的,多声明的事务,你可以增加此值来获取更大的性能.<br />
# 所有从事务来的状态都将被缓冲在binlog缓冲中然后在提交后一次性写入到binlog中<br />
# 如果事务比此值大, 会使用磁盘上的临时文件来替代.<br />
# 此缓冲在每个连接的事务第一次更新状态时被创建<br />
binlog_cache_size = 1M</p>
<p># 独立的内存表所允许的最大容量.<br />
# 此选项为了防止意外创建一个超大的内存表导致永尽所有的内存资源.<br />
max_heap_table_size = 64M</p>
<p># 排序缓冲被用来处理类似ORDER BY以及GROUP BY队列所引起的排序<br />
# 如果排序后的数据无法放入排序缓冲,<br />
# 一个用来替代的基于磁盘的合并分类会被使用<br />
# 查看 &#8220;Sort_merge_passes&#8221; 状态变量.<br />
# 在排序发生时由每个线程分配<br />
sort_buffer_size = 8M</p>
<p># 此缓冲被使用来优化全联合(full JOINs 不带索引的联合).<br />
# 类似的联合在极大多数情况下有非常糟糕的性能表现,<br />
# 但是将此值设大能够减轻性能影响.<br />
# 通过 &#8220;Select_full_join&#8221; 状态变量查看全联合的数量<br />
# 当全联合发生时,在每个线程中分配<br />
join_buffer_size = 8M</p>
<p># 我们在cache中保留多少线程用于重用<br />
# 当一个客户端断开连接后,如果cache中的线程还少于thread_cache_size,<br />
# 则客户端线程被放入cache中.<br />
# 这可以在你需要大量新连接的时候极大的减少线程创建的开销<br />
# (一般来说如果你有好的线程模型的话,这不会有明显的性能提升.)<br />
thread_cache_size = 8</p>
<p># 此允许应用程序给予线程系统一个提示在同一时间给予渴望被运行的线程的数量.<br />
# 此值只对于支持 thread_concurrency() 函数的系统有意义( 例如Sun Solaris).<br />
# 你可可以尝试使用 [CPU数量]*(2..4) 来作为thread_concurrency的值<br />
thread_concurrency = 8</p>
<p># 查询缓冲常被用来缓冲 SELECT 的结果并且在下一次同样查询的时候不再执行直接返回结果.<br />
# 打开查询缓冲可以极大的提高服务器速度, 如果你有大量的相同的查询并且很少修改表.<br />
# 查看 &#8220;Qcache_lowmem_prunes&#8221; 状态变量来检查是否当前值对于你的负载来说是否足够高.<br />
# 注意: 在你表经常变化的情况下或者如果你的查询原文每次都不同,<br />
# 查询缓冲也许引起性能下降而不是性能提升.<br />
query_cache_size = 64M</p>
<p># 只有小于此设定值的结果才会被缓冲<br />
# 此设置用来保护查询缓冲,防止一个极大的结果集将其他所有的查询结果都覆盖.<br />
query_cache_limit = 2M</p>
<p># 被全文检索索引的最小的字长.<br />
# 你也许希望减少它,如果你需要搜索更短字的时候.<br />
# 注意在你修改此值之后,<br />
# 你需要重建你的 FULLTEXT 索引<br />
ft_min_word_len = 4</p>
<p># 如果你的系统支持 memlock() 函数,你也许希望打开此选项用以让运行中的mysql在在内存高度紧张的时候,数据在内存中保持锁定并且防止可能被swapping out<br />
# 此选项对于性能有益<br />
#memlock</p>
<p># 当创建新表时作为默认使用的表类型,<br />
# 如果在创建表示没有特别执行表类型,将会使用此值<br />
default_table_type = MYISAM</p>
<p># 线程使用的堆大小. 此容量的内存在每次连接时被预留.<br />
# MySQL 本身常不会需要超过64K的内存<br />
# 如果你使用你自己的需要大量堆的UDF函数<br />
# 或者你的操作系统对于某些操作需要更多的堆,<br />
# 你也许需要将其设置的更高一点.<br />
thread_stack = 192K</p>
<p># 设定默认的事务隔离级别.可用的级别如下:<br />
# READ-UNCOMMITTED, READ-COMMITTED, REPEATABLE-READ, SERIALIZABLE<br />
transaction_isolation = REPEATABLE-READ</p>
<p># 内部(内存中)临时表的最大大小<br />
# 如果一个表增长到比此值更大,将会自动转换为基于磁盘的表.<br />
# 此限制是针对单个表的,而不是总和.<br />
tmp_table_size = 64M</p>
<p># 打开二进制日志功能.<br />
# 在复制(replication)配置中,作为MASTER主服务器必须打开此项<br />
# 如果你需要从你最后的备份中做基于时间点的恢复,你也同样需要二进制日志.<br />
log-bin=mysql-bin</p>
<p># 如果你在使用链式从服务器结构的复制模式 (A->B->C),<br />
# 你需要在服务器B上打开此项.<br />
# 此选项打开在从线程上重做过的更新的日志,<br />
# 并将其写入从服务器的二进制日志.<br />
#log_slave_updates</p>
<p># 打开全查询日志. 所有的由服务器接收到的查询 (甚至对于一个错误语法的查询)<br />
# 都会被记录下来. 这对于调试非常有用, 在生产环境中常常关闭此项.<br />
#log</p>
<p># 将警告打印输出到错误log文件.  如果你对于MySQL有任何问题<br />
# 你应该打开警告log并且仔细审查错误日志,查出可能的原因.<br />
#log_warnings</p>
<p># 记录慢速查询. 慢速查询是指消耗了比 &#8220;long_query_time&#8221; 定义的更多时间的查询.<br />
# 如果 log_long_format 被打开,那些没有使用索引的查询也会被记录.<br />
# 如果你经常增加新查询到已有的系统内的话. 一般来说这是一个好主意,<br />
log_slow_queries</p>
<p># 所有的使用了比这个时间(以秒为单位)更多的查询会被认为是慢速查询.<br />
# 不要在这里使用&#8221;1&#8243;, 否则会导致所有的查询,甚至非常快的查询页被记录下来(由于MySQL 目前时间的精确度只能达到秒的级别).<br />
long_query_time = 2</p>
<p># 在慢速日志中记录更多的信息.<br />
# 一般此项最好打开.<br />
# 打开此项会记录使得那些没有使用索引的查询也被作为到慢速查询附加到慢速日志里<br />
log_long_format</p>
<p># 此目录被MySQL用来保存临时文件.例如,<br />
# 它被用来处理基于磁盘的大型排序,和内部排序一样.<br />
# 以及简单的临时表.<br />
# 如果你不创建非常大的临时文件,将其放置到 swapfs/tmpfs 文件系统上也许比较好<br />
# 另一种选择是你也可以将其放置在独立的磁盘上.<br />
# 你可以使用&#8221;;&#8221;来放置多个路径<br />
# 他们会按照roud-robin方法被轮询使用.<br />
#tmpdir = /tmp</p>
<p># ***  复制有关的设置</p>
<p># 唯一的服务辨识号,数值位于 1 到 2^32-1之间.<br />
# 此值在master和slave上都需要设置.<br />
# 如果 &#8220;master-host&#8221; 没有被设置,则默认为1, 但是如果忽略此选项,MySQL不会作为master生效.<br />
server-id = 1</p>
<p># 复制的Slave (去掉master段的注释来使其生效)<br />
#<br />
# 为了配置此主机作为复制的slave服务器,你可以选择两种方法:<br />
#<br />
# 1) 使用 CHANGE MASTER TO 命令 (在我们的手册中有完整描述) -<br />
#    语法如下:<br />
#<br />
#    CHANGE MASTER TO MASTER_HOST=<host>, MASTER_PORT=
<port>,<br />
#    MASTER_USER=<user>, MASTER_PASSWORD=
<password> ;<br />
#<br />
#    你需要替换掉 <host>, <user>,
<password> 等被尖括号包围的字段以及使用master的端口号替换
<port> (默认3306).<br />
#<br />
#    例子:<br />
#<br />
#    CHANGE MASTER TO MASTER_HOST=&#8217;125.564.12.1&#8242;, MASTER_PORT=3306,<br />
#    MASTER_USER=&#8217;joe&#8217;, MASTER_PASSWORD=&#8217;secret&#8217;;<br />
#<br />
# 或者<br />
#<br />
# 2) 设置以下的变量. 不论如何, 在你选择这种方法的情况下, 然后第一次启动复制(甚至不成功的情况下,<br />
#     例如如果你输入错密码在master-password字段并且slave无法连接),<br />
#    slave会创建一个 master.info 文件,并且之后任何对于包含在此文件内的参数的变化都会被忽略<br />
#    并且由 master.info 文件内的内容覆盖, 除非你关闭slave服务, 删除 master.info 并且重启slave 服务.<br />
#    由于这个原因,你也许不想碰一下的配置(注释掉的) 并且使用 CHANGE MASTER TO (查看上面) 来代替<br />
#<br />
# 所需要的唯一id号位于 2 和 2^32 &#8211; 1之间<br />
# (并且和master不同)<br />
# 如果master-host被设置了.则默认值是2<br />
# 但是如果省略,则不会生效<br />
#server-id = 2<br />
#<br />
# 复制结构中的master &#8211; 必须<br />
#master-host = <hostname><br />
#<br />
# 当连接到master上时slave所用来认证的用户名 &#8211; 必须<br />
#master-user = <username><br />
#<br />
# 当连接到master上时slave所用来认证的密码 &#8211; 必须<br />
#master-password =
<password>
#<br />
# master监听的端口.<br />
# 可选 &#8211; 默认是3306<br />
#master-port =
<port>
<p># 使得slave只读.只有用户拥有SUPER权限和在上面的slave线程能够修改数据.<br />
# 你可以使用此项去保证没有应用程序会意外的修改slave而不是master上的数据<br />
#read_only</p>
<p>#*** MyISAM 相关选项</p>
<p># 关键词缓冲的大小, 一般用来缓冲MyISAM表的索引块.<br />
# 不要将其设置大于你可用内存的30%,<br />
# 因为一部分内存同样被OS用来缓冲行数据<br />
# 甚至在你并不使用MyISAM 表的情况下, 你也需要仍旧设置起 8-64M 内存由于它同样会被内部临时磁盘表使用.<br />
key_buffer_size = 32M</p>
<p># 用来做MyISAM表全表扫描的缓冲大小.<br />
# 当全表扫描需要时,在对应线程中分配.<br />
read_buffer_size = 2M</p>
<p># 当在排序之后,从一个已经排序好的序列中读取行时,行数据将从这个缓冲中读取来防止磁盘寻道.<br />
# 如果你增高此值,可以提高很多ORDER BY的性能.<br />
# 当需要时由每个线程分配<br />
read_rnd_buffer_size = 16M</p>
<p># MyISAM 使用特殊的类似树的cache来使得突发插入<br />
# (这些插入是,INSERT &#8230; SELECT, INSERT &#8230; VALUES (&#8230;), (&#8230;), &#8230;, 以及 LOAD DATA<br />
# INFILE) 更快. 此变量限制每个进程中缓冲树的字节数.<br />
# 设置为 0 会关闭此优化.<br />
# 为了最优化不要将此值设置大于 &#8220;key_buffer_size&#8221;.<br />
# 当突发插入被检测到时此缓冲将被分配.<br />
bulk_insert_buffer_size = 64M</p>
<p># 此缓冲当MySQL需要在 REPAIR, OPTIMIZE, ALTER 以及 LOAD DATA INFILE 到一个空表中引起重建索引时被分配.<br />
# 这在每个线程中被分配.所以在设置大值时需要小心.<br />
myisam_sort_buffer_size = 128M</p>
<p># MySQL重建索引时所允许的最大临时文件的大小 (当 REPAIR, ALTER TABLE 或者 LOAD DATA INFILE).<br />
# 如果文件大小比此值更大,索引会通过键值缓冲创建(更慢)<br />
myisam_max_sort_file_size = 10G</p>
<p># 如果被用来更快的索引创建索引所使用临时文件大于制定的值,那就使用键值缓冲方法.<br />
# 这主要用来强制在大表中长字串键去使用慢速的键值缓冲方法来创建索引.<br />
myisam_max_extra_sort_file_size = 10G</p>
<p># 如果一个表拥有超过一个索引, MyISAM 可以通过并行排序使用超过一个线程去修复他们.<br />
# 这对于拥有多个CPU以及大量内存情况的用户,是一个很好的选择.<br />
myisam_repair_threads = 1</p>
<p># 自动检查和修复没有适当关闭的 MyISAM 表.<br />
myisam_recover</p>
<p># 默认关闭 Federated<br />
skip-federated</p>
<p># *** BDB 相关选项 ***</p>
<p># 如果你运行的MySQL服务有BDB支持但是你不准备使用的时候使用此选项. 这会节省内存并且可能加速一些事.<br />
skip-bdb</p>
<p># *** INNODB 相关选项 ***</p>
<p># 如果你的MySQL服务包含InnoDB支持但是并不打算使用的话,<br />
# 使用此选项会节省内存以及磁盘空间,并且加速某些部分<br />
#skip-innodb</p>
<p># 附加的内存池被InnoDB用来保存 metadata 信息<br />
# 如果InnoDB为此目的需要更多的内存,它会开始从OS这里申请内存.<br />
# 由于这个操作在大多数现代操作系统上已经足够快, 你一般不需要修改此值.<br />
# SHOW INNODB STATUS 命令会显示当先使用的数量.<br />
innodb_additional_mem_pool_size = 16M</p>
<p># InnoDB使用一个缓冲池来保存索引和原始数据, 不像 MyISAM.<br />
# 这里你设置越大,你在存取表里面数据时所需要的磁盘I/O越少.<br />
# 在一个独立使用的数据库服务器上,你可以设置这个变量到服务器物理内存大小的80%<br />
# 不要设置过大,否则,由于物理内存的竞争可能导致操作系统的换页颠簸.<br />
# 注意在32位系统上你每个进程可能被限制在 2-3.5G 用户层面内存限制,<br />
# 所以不要设置的太高.<br />
innodb_buffer_pool_size = 2G</p>
<p># InnoDB 将数据保存在一个或者多个数据文件中成为表空间.<br />
# 如果你只有单个逻辑驱动保存你的数据,一个单个的自增文件就足够好了.<br />
# 其他情况下.每个设备一个文件一般都是个好的选择.<br />
# 你也可以配置InnoDB来使用裸盘分区 &#8211; 请参考手册来获取更多相关内容<br />
innodb_data_file_path = ibdata1:10M:autoextend</p>
<p># 设置此选项如果你希望InnoDB表空间文件被保存在其他分区.<br />
# 默认保存在MySQL的datadir中.<br />
#innodb_data_home_dir = <directory></p>
<p># 用来同步IO操作的IO线程的数量. This value is<br />
# 此值在Unix下被硬编码为4,但是在Windows磁盘I/O可能在一个大数值下表现的更好.<br />
innodb_file_io_threads = 4</p>
<p># 如果你发现InnoDB表空间损坏, 设置此值为一个非零值可能帮助你导出你的表.<br />
# 从1开始并且增加此值知道你能够成功的导出表.<br />
#innodb_force_recovery=1</p>
<p># 在InnoDb核心内的允许线程数量.<br />
# 最优值依赖于应用程序,硬件以及操作系统的调度方式.<br />
# 过高的值可能导致线程的互斥颠簸.<br />
innodb_thread_concurrency = 16</p>
<p># 如果设置为1 ,InnoDB会在每次提交后刷新(fsync)事务日志到磁盘上,<br />
# 这提供了完整的ACID行为.<br />
# 如果你愿意对事务安全折衷, 并且你正在运行一个小的食物, 你可以设置此值到0或者2来减少由事务日志引起的磁盘I/O<br />
# 0代表日志只大约每秒写入日志文件并且日志文件刷新到磁盘.<br />
# 2代表日志写入日志文件在每次提交后,但是日志文件只有大约每秒才会刷新到磁盘上.<br />
innodb_flush_log_at_trx_commit = 1</p>
<p># 加速InnoDB的关闭. 这会阻止InnoDB在关闭时做全清除以及插入缓冲合并.<br />
# 这可能极大增加关机时间, 但是取而代之的是InnoDB可能在下次启动时做这些操作.<br />
#innodb_fast_shutdown</p>
<p># 用来缓冲日志数据的缓冲区的大小.<br />
# 当此值快满时, InnoDB将必须刷新数据到磁盘上.<br />
# 由于基本上每秒都会刷新一次,所以没有必要将此值设置的太大(甚至对于长事务而言)</p>
<p>innodb_log_buffer_size = 8M</p>
<p># 在日志组中每个日志文件的大小.<br />
# 你应该设置日志文件总合大小到你缓冲池大小的25%~100%<br />
# 来避免在日志文件覆写上不必要的缓冲池刷新行为.<br />
# 不论如何, 请注意一个大的日志文件大小会增加恢复进程所需要的时间.<br />
innodb_log_file_size = 256M</p>
<p># 在日志组中的文件总数.<br />
# 通常来说2~3是比较好的.<br />
innodb_log_files_in_group = 3</p>
<p># InnoDB的日志文件所在位置. 默认是MySQL的datadir.<br />
# 你可以将其指定到一个独立的硬盘上或者一个RAID1卷上来提高其性能<br />
#innodb_log_group_home_dir</p>
<p># 在InnoDB缓冲池中最大允许的脏页面的比例.<br />
# 如果达到限额, InnoDB会开始刷新他们防止他们妨碍到干净数据页面.<br />
# 这是一个软限制,不被保证绝对执行.<br />
innodb_max_dirty_pages_pct = 90</p>
<p># InnoDB用来刷新日志的方法.<br />
# 表空间总是使用双重写入刷新方法<br />
# 默认值是 &#8220;fdatasync&#8221;, 另一个是 &#8220;O_DSYNC&#8221;.<br />
#innodb_flush_method=O_DSYNC</p>
<p># 在被回滚前,一个InnoDB的事务应该等待一个锁被批准多久.<br />
# InnoDB在其拥有的锁表中自动检测事务死锁并且回滚事务.<br />
# 如果你使用 LOCK TABLES 指令, 或者在同样事务中使用除了InnoDB以外的其他事务安全的存储引擎<br />
# 那么一个死锁可能发生而InnoDB无法注意到.<br />
# 这种情况下这个timeout值对于解决这种问题就非常有帮助.<br />
innodb_lock_wait_timeout = 120</p>
<p>[mysqldump]<br />
# 不要在将内存中的整个结果写入磁盘之前缓存. 在导出非常巨大的表时需要此项<br />
quick</p>
<p>max_allowed_packet = 16M</p>
<p>[mysql]<br />
no-auto-rehash</p>
<p># 仅仅允许使用键值的 UPDATEs 和 DELETEs .<br />
#safe-updates</p>
<p>[isamchk]<br />
key_buffer = 512M<br />
sort_buffer_size = 512M<br />
read_buffer = 8M<br />
write_buffer = 8M</p>
<p>[myisamchk]<br />
key_buffer = 512M<br />
sort_buffer_size = 512M<br />
read_buffer = 8M<br />
write_buffer = 8M</p>
<p>[mysqlhotcopy]<br />
interactive-timeout</p>
<p>[mysqld_safe]<br />
# 增加每个进程的可打开文件数量.<br />
# 警告: 确认你已经将全系统限制设定的足够高!<br />
# 打开大量表需要将此值设高<br />
open-files-limit = 8192<br />
</directory></port></password></username></hostname></port></password></user></host></password></user></port></host></p>
]]></content:encoded>
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		<item>
		<title>nginx多域名站点rewrite跳转不改变域名的方法：server_name_in_redirec用法</title>
		<link>http://226617.cn/archives/402.htm</link>
		<comments>http://226617.cn/archives/402.htm#comments</comments>
		<pubDate>Thu, 15 Jan 2009 14:21:08 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[nginx相关]]></category>
		<category><![CDATA[nginx]]></category>
		<category><![CDATA[rewrite]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=402</guid>
		<description><![CDATA[nginx中如果一个server节点有多个域名，并且在不是访问主域名的情况下如果进行rewrite跳转，会自动把域名转换成主域名。比如： 1 2 3 4 5 server { server_name www.my.com www.site.com; rewrite ^/$ /src/login.php re... ]]></description>
			<content:encoded><![CDATA[<p>nginx中如果一个server节点有多个域名，并且在不是访问主域名的情况下如果进行rewrite跳转，会自动把域名转换成主域名。比如：</p>

<div class="wp_syntax"><table><tr><td class="line_numbers"><pre>1
2
3
4
5
</pre></td><td class="code"><pre class="nginx" style="font-family:monospace;">server {
   server_name www.my.com www.site.com;
   rewrite ^/$ /src/login.php redirect;
   ......
}</pre></td></tr></table></div>

<p>这里如果访问www.site.com的话会自动跳转到www.my.com/src/login.php，而不是www.site.com/src/login.php。</p>
<p>解决方法：<br />
如果nginx版本在0.6.x及以上版本的话使用</p>

<div class="wp_syntax"><table><tr><td class="line_numbers"><pre>1
2
3
4
5
6
</pre></td><td class="code"><pre class="nginx" style="font-family:monospace;">server {
   server_name www.my.com www.site.com;
   server_name_in_redirect  off;
   rewrite ^/$ /src/login.php redirect;
   ......
}</pre></td></tr></table></div>

<p>老版本的话可以使用</p>

<div class="wp_syntax"><table><tr><td class="line_numbers"><pre>1
2
3
4
5
6
7
</pre></td><td class="code"><pre class="nginx" style="font-family:monospace;">server {
   server_name www.my.com www.site.com;
   location = / {
      rewrite ^ /src/login.php redirect;
   }
   ......
}</pre></td></tr></table></div>

<p>关键点：<br />
如果server_name_in_redirec为on，那么nginx将使用server_name中的第一个 server name来进行rewrite跳转。如果设置成off的话nginx将使用请求中Request Headers中的host来进行rewrite跳转。<br />
server_name_in_redirec 可以在配置文件中 http , server 和 location 区域级别中使用。</p>
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		</item>
		<item>
		<title>nginx支持泛域名支持的方法</title>
		<link>http://226617.cn/archives/399.htm</link>
		<comments>http://226617.cn/archives/399.htm#comments</comments>
		<pubDate>Thu, 15 Jan 2009 14:01:45 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[nginx相关]]></category>
		<category><![CDATA[nginx]]></category>
		<category><![CDATA[泛域名]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=399</guid>
		<description><![CDATA[要使用Nginx下的泛域名支持，必须在编译 Nginx的时候加上 &#8211;with-http_sub_module 然后使用 1 2 3 4 5 server { listen 80; server_name _; ..... ... ]]></description>
			<content:encoded><![CDATA[<p>要使用Nginx下的泛域名支持，必须在编译 Nginx的时候加上<br />
&#8211;with-http_sub_module</p>
<p>然后使用</p>

<div class="wp_syntax"><table><tr><td class="line_numbers"><pre>1
2
3
4
5
</pre></td><td class="code"><pre class="nginx" style="font-family:monospace;">server {
listen       80;
server_name  _;
.....
}</pre></td></tr></table></div>

]]></content:encoded>
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		</item>
		<item>
		<title>nginx配置文件中的rewrite参数</title>
		<link>http://226617.cn/archives/394.htm</link>
		<comments>http://226617.cn/archives/394.htm#comments</comments>
		<pubDate>Thu, 15 Jan 2009 08:22:16 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[nginx相关]]></category>
		<category><![CDATA[nginx]]></category>
		<category><![CDATA[rewrite]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=394</guid>
		<description><![CDATA[正则表达式匹配，其中： * ~ 为区分大小写匹配 * ~* 为不区分大小写匹配 * !~和!~*分别为区分大小写不匹配及不区分大小写不匹配 文件及目录匹配，其中： * -f和!-f用来判断是否存在文件 * -d和!-... ]]></description>
			<content:encoded><![CDATA[<p>正则表达式匹配，其中：<br />
* ~ 为区分大小写匹配<br />
* ~* 为不区分大小写匹配<br />
* !~和!~*分别为区分大小写不匹配及不区分大小写不匹配</p>
<p>文件及目录匹配，其中：<br />
* -f和!-f用来判断是否存在文件<br />
* -d和!-d用来判断是否存在目录<br />
* -e和!-e用来判断是否存在文件或目录<br />
* -x和!-x用来判断文件是否可执行</p>
<p>flag标记有：<br />
* last 相当于Apache里的[L]标记，表示完成rewrite<br />
* break 终止匹配, 不再匹配后面的规则<br />
* redirect 返回302临时重定向<br />
* permanent 返回301永久重定向</p>
<p>一些可用的全局变量有，可以用做条件判断(待补全)<br />
$args<br />
$content_length<br />
$content_type<br />
$document_root<br />
$document_uri<br />
$host<br />
$http_user_agent<br />
$http_cookie<br />
$limit_rate<br />
$request_body_file<br />
$request_method<br />
$remote_addr<br />
$remote_port<br />
$remote_user<br />
$request_filename<br />
$request_uri<br />
$query_string<br />
$scheme<br />
$server_protocol<br />
$server_addr<br />
$server_name<br />
$server_port<br />
$uri </p>
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		<title>nginx配置文件中的location中文详解</title>
		<link>http://226617.cn/archives/392.htm</link>
		<comments>http://226617.cn/archives/392.htm#comments</comments>
		<pubDate>Thu, 15 Jan 2009 03:46:15 +0000</pubDate>
		<dc:creator>龙飞</dc:creator>
				<category><![CDATA[nginx相关]]></category>
		<category><![CDATA[location]]></category>
		<category><![CDATA[nginx]]></category>

		<guid isPermaLink="false">http://226617.cn/?p=392</guid>
		<description><![CDATA[location 语法:location [=&#124;~&#124;~*&#124;^~] /uri/ { … } 默认:否 上下文:server 这个指令随URL不同而接受不同的结构。你可以配置使用常规字符串和正则表达式。如果使用正则表达式，你必须使用 ~* 前... ]]></description>
			<content:encoded><![CDATA[<p>location</p>
<p>语法:location [=|~|~*|^~] /uri/ { … }<br />
默认:否</p>
<p>上下文:server</p>
<p>这个指令随URL不同而接受不同的结构。你可以配置使用常规字符串和正则表达式。如果使用正则表达式，你必须使用 ~* 前缀选择不区分大小写的匹配或者 ~ 选择区分大小写的匹配。</p>
<p>确定 哪个location 指令匹配一个特定指令，常规字符串第一个测试。常规字符串匹配请求的开始部分并且区分大小写，最明确的匹配将会被使用（查看下文明白 nginx 怎么确定它）。然后正则表达式按照配置文件里的顺序测试。找到第一个比配的正则表达式将停止搜索。如果没有找到匹配的正则表达式，使用常规字符串的结果。</p>
<p>有两个方法修改这个行为。第一个方法是使用 “=”前缀，将只执行严格匹配。如果这个查询匹配，那么将停止搜索并立即处理这个请求。例子：如果经常发生”/”请求，那么使用 “location = /” 将加速处理这个请求。</p>
<p>第二个是使用 ^~ 前缀。如果把这个前缀用于一个常规字符串那么告诉nginx 如果路径匹配那么不测试正则表达式。</p>
<p>而且它重要在于 NGINX 做比较没有 URL 编码，所以如果你有一个 URL 链接’/images/%20/test’ , 那么使用 “images/ /test” 限定location。</p>
<p>总结，指令按下列顺序被接受:<br />
1. = 前缀的指令严格匹配这个查询。如果找到，停止搜索。<br />
2. 剩下的常规字符串，长的在前。如果这个匹配使用 ^~ 前缀，搜索停止。<br />
3. 正则表达式，按配置文件里的顺序。<br />
4. 如果第三步产生匹配，则使用这个结果。否则使用第二步的匹配结果。</p>
<p>例子：</p>
<p>location = / {<br />
# 只匹配 / 查询。<br />
[ configuration A ]<br />
}</p>
<p>location / {<br />
# 匹配任何查询，因为所有请求都已 / 开头。但是正则表达式规则和长的块规则将被优先和查询匹配。<br />
[ configuration B ]<br />
}</p>
<p>location ^~ /images/ {<br />
# 匹配任何已 /images/ 开头的任何查询并且停止搜索。任何正则表达式将不会被测试。<br />
[ configuration C ]<br />
}</p>
<p>location ~* \.(gif|jpg|jpeg)$ {<br />
# 匹配任何已 gif、jpg 或 jpeg 结尾的请求。然而所有 /images/ 目录的请求将使用 Configuration C。<br />
[ configuration D ]<br />
}</p>
<p>例子请求:</p>
<p>/ -> configuration A</p>
<p>/documents/document.html -> configuration B</p>
<p>/images/1.gif -> configuration C</p>
<p>/documents/1.jpg -> configuration D</p>
<p>注意：按任意顺序定义这4个配置结果将仍然一样。</p>
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