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怎样去查找并杀掉非法的MySQL查询
有时,相关数据库系统的复杂性可能被压倒.幸运地,这种复杂性是一种优势,与 MySQL工具一起管理查询. 在本教程中, 我将向你们展示 怎样去查找并杀掉任何非法的MySQL查询.
为了浏览当前正在运行的查询, 登陆到MySQL终端，然后运行‘show processlist’命令:
mysql> show processlist;
+--------+--------+-----------------+---------+---------+-------+-------+------------------+-----------+---------------+-----------+
| Id | User | Host | db | Command | Time | State | Info | Rows_sent | Rows_examined | Rows_read |
+--------+--------+-----------------+---------+---------+-------+-------+------------------+-----------+---------------+-----------+
| 78233 | root | 127.0.0.1:37527 | mysql | Sleep | 16474 | | NULL | 6 | 6 | 6 |
| 84546 | root | 127.0.0.1:48593 | mysql | Sleep | 13237 | | NULL | 2 | 2 | 2 |
| 107083 | root | 127.0.0.1:56451 | mysql | Sleep | 15488 | | NULL | 1 | 121 | 121 |
| 131455 | root | 127.0.0.1:48550 | NULL | Query | 0 | NULL | show processlist | 0 | 0 | 0 |
+--------+--------+-----------------+---------+---------+-------+-------+------------------+-----------+---------------+-----------+
4 rows in set (0.03 sec)
首先 你应该查看'Time'项, 这里记录了进程执行 "doing the thing it's doing" 操作的秒数. ‘command’项处于‘Sleep’ 状态的进程正在等待查询, 因此,它并没有消耗任何资源. 对于其他任何进程而言，‘Time’超过一定的秒数表明出现问题.
在这种情况下,只能通过运行‘show processlist’命令来查询.如果我们有一个糟糕的写查询，让我们来看看情况如何:
mysql> show processlist;
+--------+--------+-----------------+-----------+---------+-------+--------------+----------------------------------+-----------+---------------+-----------+
| Id | User | Host | db | Command | Time | State | Info | Rows_sent | Rows_examined | Rows_read |
+--------+--------+-----------------+-----------+---------+-------+--------------+----------------------------------+-----------+---------------+-----------+
| 78233 | root | 127.0.0.1:37527 | example | Sleep | 18046 | | NULL | 6 | 6 | 6 |
| 84546 | root | 127.0.0.1:48593 | example | Sleep | 14809 | | NULL | 2 | 2 | 2 |
| 107083 | root | 127.0.0.1:56451 | example | Sleep | 17060 | | NULL | 1 | 121 | 121 |
| 132033 | root | 127.0.0.1:54642 | example | Query | 27 | Sending data | select max(subtotal) from orders | 0 | 0 | 0 |
| 133933 | root | 127.0.0.1:48679 | NULL | Query | 0 | NULL | show processlist | 0 | 0 | 0 |
| 134122 | root | 127.0.0.1:49264 | example | Sleep | 0 | | NULL | 0 | 0 | 0 |
+--------+--------+-----------------+-----------+---------+-------+--------------+----------------------------------+-----------+---------------+-----------+
6 rows in set (0.00 sec)
啊哈！现在我们看到这里的查询几乎运行了30s. 如果我们不想让它继续运行，可以使用它的'Id'去执行kill命令:
mysql> kill 132033;
Query OK, 0 rows affected (0.00 sec)
mysql>
(注意 由于我们没有改变任何数据,MySQL总是报告0行被影响.)
明智的使用kill命令能够清除积压的查询.记住,但那不是一种永久的方法 - 如果这些查询来自你的应用,你需要去重写它们,或者将继续看到相同的问题.
另请参阅
关于不同‘Command’的MySQL文档:
via: http://xmodulo.com/2014/07/find-kill-misbehaving-mysql-queries.html
译者：hunanchenxingyu 校对：校对者ID