From 01a7a2009f435a9aafc5f4bff0c794af39356dcc Mon Sep 17 00:00:00 2001 From: DeadFire Date: Thu, 3 Jul 2014 14:39:54 +0800 Subject: [PATCH] =?UTF-8?q?20140703-2=20=E9=80=89=E9=A2=98=20=E6=8A=80?= =?UTF-8?q?=E6=9C=AF=E6=96=87=E7=AB=A0=E4=B8=80=E7=AF=87?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- ...find and kill misbehaving MySQL queries.md | 61 +++++++++++++++++++ 1 file changed, 61 insertions(+) create mode 100644 sources/tech/20140703 How to find and kill misbehaving MySQL queries.md diff --git a/sources/tech/20140703 How to find and kill misbehaving MySQL queries.md b/sources/tech/20140703 How to find and kill misbehaving MySQL queries.md new file mode 100644 index 0000000000..f4eebccfcd --- /dev/null +++ b/sources/tech/20140703 How to find and kill misbehaving MySQL queries.md @@ -0,0 +1,61 @@ +How to find and kill misbehaving MySQL queries +================================================================================ +Sometimes the complexity of a relational database system can be overwhelming. Fortunately, that complexity is an advantage, as with MySQL's tools for managing queries. In this tutorial, I will show you **how to find and kill any misbehaving MySQL queries**. + +To view the currently-running queries, log in to the MySQL console and run the 'show processlist' command: + + 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) + +The first column you should look at is 'Time', which is the number of seconds the process has been "doing the thing it's doing". A process whose command is 'Sleep' is waiting for a query to come in, so it's not consuming any resources. For any other process, however, a 'Time' of more than a few seconds indicates a problem. + +In this case, the only query running is our 'show processlist' command. Let's see what it looks like if we have a poorly-written query running: + + 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) + +Ah! Now we see there is a query that's been running for almost 30 seconds. If we don't want to let it run its course, we can kill it by passing its 'Id' to the kill command: + + mysql> kill 132033; + Query OK, 0 rows affected (0.00 sec) + mysql> + +(Note that MySQL will always report 0 rows affected, because we're not altering any data.) + +Judicious use of the kill command can clean up a backlog of queries. Remember, however, that it's not a permanent solution - if those queries came from your application, you need to rewrite them, or you'll continue to see the same issue reappear. + +### See Also ### + +MySQL's documentation on the different 'Command' values: + +- [https://dev.mysql.com/doc/refman/5.7/en/thread-commands.html][1] + +-------------------------------------------------------------------------------- + +via: http://xmodulo.com/2014/07/find-kill-misbehaving-mysql-queries.html + +译者：[译者ID](https://github.com/译者ID) 校对：[校对者ID](https://github.com/校对者ID) + +本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创翻译，[Linux中国](http://linux.cn/) 荣誉推出 + +[1]:https://dev.mysql.com/doc/refman/5.7/en/thread-commands.html \ No newline at end of file