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MySQL的wait_timeout_MySQL

程序员文章站 2022-06-01 19:10:04
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没有修改过MySQL的配置,缺省情况下,wait_timeout的初始值是28800

wait_timeout过大有弊端,其体现就是MySQL里大量的SLEEP进程无法及时释放,拖累系统性能,不过也不能把这个指设置的过小,否则你可能会遭遇到“MySQL has gone away”之类的问题

mysql> set global wait_timeout=20;

mysql> show global variables like 'wait_timeout';
+----------------------------+-------+
| Variable_name | Value |
+----------------------------+-------+
| wait_timeout |20 |
+----------------------------+-------+


今天发现很多sleep的进程,mysql给出的原因为3个:


1 The client program did not call mysql_close() before exiting.

2 The client had been sleeping more than wait_timeout or interactive_timeout seconds without issuing any requests to the server.

3 The client program ended abruptly in the middle of a data transfer