MySQL错误 ERROR 2002 (HY000): Can't connect to local MySQL server through socket 的解决办法

原因分析：

1、没有 /var/lib/mysql/mysql.sock 的目录权限

添加权限 chown -r mysql:mysql /var/lib/mysql/

2、没有/var/lib/mysql/mysql.sock文件

通过 find / -name mysql.sock

在 /tmp//mysql.sock

用 ln -s 命令建立连接

或者修改 /etc/my.cnf配置文件，下边有，然后重启

#查看mysql实例的状态
[root@szdb mysqldata]# netstat -ntlp  | grep 3306
tcp        0      0 :::3306                     :::*                        listen      13001/mysqld
#查看my.cnf关于socket的配置
[root@szdb mysqldata]# more /etc/my.cnf |grep sock
socket = /tmp/mysql.sock
#由上可知my.cnf中定义的为/tmp目录下，而错误提示为/data/mysqldata/目录下
#也就是说mysqld已经声称了正确的sock文件，但客户端连接还是从初始目录去找sock文件
#下面查看后台日志，有个error，是关于满查询日志的，是由于目录不存在而产生的错误，与当前故障无关
[root@szdb mysqldata]# more szdb.err
             ............
2014-10-11 13:17:21 13001 [note] innodb: 5.6.12 started; log sequence number 1625997
/app/soft/mysql/bin/mysqld: file '/log/mysql_logs/slowquery.log' not found (errcode: 2 - no such file or directory)
2014-10-11 13:17:21 13001 [error] could not use /log/mysql_logs/slowquery.log for logging (error 2). turning logging off for the who
le duration of the mysql server process. to turn it on again: fix the cause, shutdown the mysql server and restart it.
2014-10-11 13:17:21 13001 [note] server hostname (bind-address): '*'; port: 3306
2014-10-11 13:17:21 13001 [note] ipv6 is available.
2014-10-11 13:17:21 13001 [note]   - '::' resolves to '::';
2014-10-11 13:17:21 13001 [note] server socket created on ip: '::'.
2014-10-11 13:17:21 13001 [note] event scheduler: loaded 0 events
2014-10-11 13:17:21 13001 [note] /app/soft/mysql/bin/mysqld: ready for connections.
version: '5.6.12-log'  socket: '/tmp/mysql.sock'  port: 3306  source distribution
3、解决故障
通过配置my.cnf mysql选项socket文件位置解决
复制代码 代码如下:
#先停止mysql服务器
[root@szdb mysqldata]# service mysqld stop
shutting down mysql.[  ok  ]
#修改my.cnf，如下
[root@szdb mysqldata]# vi /etc/my.cnf
[mysql]
no-auto-rehash
socket = /tmp/mysql.sock  #添加该行
[mysql.server]
user=mysql#添加
basedir=/usr/local/mysql#添加
#if there is not currently a section called [client], add one at the bottom of the file and copy the socket= line under the [mysqld] section such as:
[client]#添加
socket=/var/lib/mysql/mysql.sock#添加
#重启mysql服务器
[root@szdb mysqldata]# service mysqld start
starting mysql..[  ok  ]
#再次连接正常
[root@szdb mysqldata]# mysql -uroot -p
enter password: 
mysql> show variables like 'version';
+---------------+------------+
| variable_name | value      |
+---------------+------------+
| version       | 5.6.12-log |
+---------------+------------+
为socket文件建立链接方式
复制代码 代码如下:
[root@szdb mysqldata]# ln -s /tmp/mysql.sock /data/mysqldata/mysql.sock 
ln: creating symbolic link `/data/mysqldata/mysql.sock' to `/tmp/mysql.sock': file exists
[root@szdb mysqldata]# rm mysql.sock    #上面提示文件存在，所以删除之前的mysql.sock文件
[root@szdb mysqldata]# ln -s /tmp/mysql.sock /data/mysqldata/mysql.sock
[root@szdb mysqldata]# ls -hltr mysql.sock
lrwxrwxrwx 1 root root 15 oct 11 14:00 mysql.sock -> /tmp/mysql.sock
[root@szdb mysqldata]# mysql -uroot -p
enter password: 
mysql> show variables like 'socket';
+---------------+-----------------+
| variable_name | value           |
+---------------+-----------------+
| socket        | /tmp/mysql.sock |
+---------------+-----------------+