MySQL 什么是mysql默认的wait_timeout和interactive_timeout
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What is the default mysql wait_timeout and interactive_timeout
提问by user2693017
I changed these timeouts globally with:
我通过以下方式全局更改了这些超时：
SET GLOBAL wait_timeout=30; SET GLOBAL interactive_timeout=30
and noticed that I have another application running which got problems with these "low" timeouts. So I would like to undo this and only apply it to the specific database.
并注意到我正在运行另一个应用程序，该应用程序遇到了这些“低”超时的问题。所以我想撤消这个，只将它应用于特定的数据库。
采纳答案by Ilia Rostovtsev
Referring to the MySQL Manualthe default values for wait_timeoutand for interactive_timeoutare - 28800.
参考MySQL 手册，wait_timeout和 for的默认值interactive_timeout是 - 28800。
On thread startup, the session wait_timeout value is initialized from the global wait_timeoutvalue or from the global interactive_timeoutvalue, depending on the type of client (as defined by the CLIENT_INTERACTIVE connect option to mysql_real_connect()). See also interactive_timeout.
在线程启动时，会话wait_timeout 值从全局wait_timeout值或全局interactive_timeout值初始化 ，这取决于客户端的类型（由mysql_real_connect() 的CLIENT_INTERACTIVE 连接选项定义）。另见interactive_timeout。
回答by gus
I have the same problem in 5.5.43. I was having the "has gone away" error message for some long queries beyond about 2 minutes. So I tried these 3:
我在5.5.43. 对于一些超过大约 2 分钟的长时间查询，我收到了“已消失”错误消息。所以我尝试了这三个：
(1) SHOW VARIABLES LIKE 'wait_%';
(1) SHOW VARIABLES LIKE 'wait_%';
(2) SHOW global VARIABLES LIKE 'wait_%';and
(2)SHOW global VARIABLES LIKE 'wait_%';和
(3) SHOW session VARIABLES LIKE 'wait_%';.
(3) SHOW session VARIABLES LIKE 'wait_%';.
All showed wait_timeout to be 28800. Then I added wait_timeout = 31536000to /etc/my.cnf. Then my long query was able to complete. And from the 3 ways of showing variables above, only (2) the one with "global" showed a change from 28800 to 31536000. The other 2 were unaffected. Since my long-query was definitely less than 10 minutes long, does this mean that the unit of time used here was millisecondsrather than seconds?
都显示 wait_timeout 为28800。然后我添加wait_timeout = 31536000到/etc/my.cnf. 然后我的长查询就可以完成了。而从上面的3种显示变量的方式来看，只有（2）有“global”的那个显示了从28800到31536000的变化，其他2种不受影响。由于我的长查询肯定少于 10 分钟，这是否意味着这里使用的时间单位是毫秒而不是秒？
