今天中午的时候突然接到报警,MySQL连接数暴增..本来设置的max_conntion=6000, 这个数值连接已经够用.接到报警速度连接服务器连接mysql总是报如下错误:

[mysql@localhost ~]$ mysql -u xxxxx -pxxxxxxxx

ERROR 1040 (HY000): Too many connections

本来打算kill杀掉重启搞定解决..但是生产库最好不要轻易重启.这里演示一种在线解决连接数满的方式..还记的神器gdb吗?没错就是它 ^_^

查看mysql后台进程

[mysql@localhost ~]$ ps -ef | grep mysql

root      1549  1281  0 16:21 ?        00:00:00 sshd: mysql [priv]

mysql     1551  1549  0 16:21 ?        00:00:00 sshd: mysql@pts/0

mysql     1552  1551  0 16:21 pts/0    00:00:00 -bash

mysql     1571  1552  0 16:21 pts/0    00:00:00 /bin/sh /usr/local/mysql/bin/mysqld_safe

mysql     1985  1571  0 16:21 pts/0    00:00:01 /usr/local/mysql/bin/mysqld --basedir=/usr/local/mysql --datadir=/mysql/data --plugin-dir=/usr/local/mysql/lib/plugin --log-error=/mysql/mysqld.log --pid-file=/mysql/mysqld.pid --socket=/tmp/mysql.sock

使用gdb修改内存中的max_connections值

[mysql@localhost ~]$ gdb -p 1985 -ex "set max_connections=10240" -batch

[New LWP 2190]

[New LWP 2094]

[New LWP 2070]

[New LWP 2039]

[New LWP 2009]

[New LWP 2007]

[New LWP 2006]

[New LWP 2005]

[New LWP 2004]

[New LWP 2003]

[New LWP 2002]

[New LWP 2001]

[New LWP 2000]

[New LWP 1999]

[New LWP 1998]

[New LWP 1996]

[New LWP 1995]

[New LWP 1994]

[New LWP 1993]

[New LWP 1992]

[New LWP 1991]

[New LWP 1990]

[New LWP 1989]

[New LWP 1988]

[New LWP 1987]

[Thread debugging using libthread_db enabled]

0x00007f5e26613343 in poll () from /lib64/libc.so.6

[mysql@localhost ~]$

现在尝试进mysql,查看max_connections值

[mysql@localhost ~]$ mysql -u xxxxx -pxxxxxxx

Welcome to the MySQL monitor.  Commands end with ; or \g.

Your MySQL connection id is 9

Server version: 5.6.15-log Source distribution

Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.

Oracle is a registered trademark of Oracle Corporation and/or its

affiliates. Other names may be trademarks of their respective

owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql> show variables like '%max_connections%';

+-----------------+-------+

| Variable_name   | Value |

+-----------------+-------+

| max_connections | 10240 |

+-----------------+-------+

1 row in set (0.00 sec)

OK.^_^终于能进去了.终于恢复正常了..迅速批量杀掉sleep进程..一般情况下报too many connection应该是程序那边出问题了.暂时解决方案扩大max_connections解决.原因等开发回来一起查吧.(坏的真不是时候,我的中午饭啊.......-_-可怜)

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