2019独角兽企业重金招聘Python工程师标准>>> 
下文描述了mysql的wait_timeout参数配置注意事项。简单的来讲要注意连接的程序用的是什么，是有状态的（如java,.net等）还是没状态的（如php,python等），有状态的wait_timeout连接时间要长（值范围60-259200），无状态的连接时间要短。mysql默认值是8小时。interactive_timeout（值范围10-86400）是用在shell交互时的超时时间。
其实很多性能优化的指导，都是如果无状态化。如缓存，静态化，轮循，分布式等，无状态很受欢迎。
Locate the timeout configuration and adjust it to fit your server.
wait_timeout = 28800
interactive_timeout = 28800
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The interactive timeout does not affect any web application connections. A high
interactive_timeoutbut a lowwait_timeoutis normal and is the best practice. -
Choose a reasonable
wait_timeoutvalue. Stateless PHP environments do well with a 60 second timeout or less. Stateful applications that use a connection pool (Java, .NET, etc.) will need to adjustwait_timeoutto match their connection pool settings. The default 8 hours (wait_timeout = 28800) works well with properly configured connection pools. -
Configure the
wait_timeoutto be slightly longer than the application connection pool’s expected connection lifetime. This is a good safety check. -
Consider changing the
wait_timeoutvalue online. This does not require a MySQL restart, and thewait_timeoutcan be adjusted in the running server without incurring downtime. You would issueset global wait_timeout=60and any new sessions created would inherit this value. Be sure to preserve the setting inmy.cnf. Any existing connections will need to hit the old value ofwait_timeoutif the application abandoned the connection. If you do have reporting jobs that will do longer local processing while in a transaction, you might consider having such jobs issueset session wait_timeout=3600upon connecting.