[英]Slow MySQL Performance & Sleep queries
最近,我注意到在凌晨时分,我网站上的AJAX数据加载非常缓慢。 使用Chrome浏览器中的Web Developer功能,通常300-500ms等待和100-300ms接收的速度最多可以增加5秒! 该网站使用jQuery,Codeigniter / PHP和MySQL。
我向我的VPS的支持台咨询了一下,他们提到有太多睡眠查询。
There are many sleep queries for the database 'databasename'.
| 4341 | mysqluser | 204.197.252.106:48669 | databasename | Sleep | 19 | | |
| 4373 | mysqluser | 204.197.252.106:59966 | databasename | Sleep | 78 | | |
| 4387 | mysqluser | 204.197.252.106:34807 | databasename | Sleep | 46 | | |
| 4388 | mysqluser | 204.197.252.106:35099 | databasename | Sleep | 6 | | |
| 4390 | mysqluser | 204.197.252.106:35452 | databasename | Sleep | 26 | | |
| 4391 | mysqluser | 204.197.252.106:35589 | databasename | Sleep | 7 | | |
| 4392 | mysqluser | 204.197.252.106:35680 | databasename | Sleep | 19 | | |
| 4393 | mysqluser | 204.197.252.106:36264 | databasename | Sleep | 12 | | |
| 4394 | mysqluser | 204.197.252.106:36327 | databasename | Sleep | 11 | | |
这是早上速度下降的原因吗? 我如何找出导致减速的原因并消除它?
如果要终止睡眠连接,可以执行以下操作:以管理员身份登录Mysql:
mysql -uroot -ppassword;
并且比运行命令:
mysql> show processlist;
您将获得以下内容:
+----+-------------+--------------------+----------+---------+------+-------+------------------+
| Id | User | Host | db | Command | Time | State | Info |
+----+-------------+--------------------+----------+---------+------+-------+------------------+
| 49 | application | 192.168.44.1:51718 | XXXXXXXX | Sleep | 183 | | NULL ||
| 55 | application | 192.168.44.1:51769 | XXXXXXXX | Sleep | 148 | | NULL |
| 56 | application | 192.168.44.1:51770 | XXXXXXXX | Sleep | 148 | | NULL |
| 57 | application | 192.168.44.1:51771 | XXXXXXXX | Sleep | 148 | | NULL |
| 58 | application | 192.168.44.1:51968 | XXXXXXXX | Sleep | 11 | | NULL |
| 59 | root | localhost | NULL | Query | 0 | NULL | show processlist |
+----+-------------+--------------------+----------+---------+------+-------+------------------+
您将看到不同连接的完整详细信息。 现在,您可以按以下方式终止睡眠连接:
mysql> kill 52;
Query OK, 0 rows affected (0.00 sec)
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