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MySQL之服务器保持与MySQL的连接_MySQL

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Jun 01, 2016 pm 12:59 PM

server

<span style="font-family: Arial, Verdana, sans-serif;">服务器程序经常要访问数据库，并且服务器程序是长时间保持运行的，mysql有一个特点，当连接上数据库后不做任何操作，默认8小时候会自动关闭休眠的连接！一般情况下很难预料什么时候程序会执行数据库操作，如果连接被mysql断开了，会出现意想不到的问题，这在服务器程序中是一种灾难！保持服务器程序与Mysql的连接一种方式是修改默认的休眠时间，但这种方式治标不治本；另一种方式很显然就是定期的执行数据库操作来保持与mysql的连接。</span>

查看默认休眠时间的方式：

登录mysql后输入命令 show variables like '%timeout%' 会出现mysql中的关于休眠超时的一些变量

其中 wait_timeout 变量为28800，即28800秒，也就是默认的8小时；

查看连接状况，使用show processlist命令

Time字段指出了当前连接的时间，默认情况下，当长时间不做任何操作，Time字段值会随着时间增大，大于28800秒时就会关闭当前连接；相反，在这默认的8小时内，如果执行了数据库操作，就会从0开始计时。

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