MySQL error ERROR 2002 of HY000: Can 't to local server through socket

After installing MySQL and using the new configuration file, the MySQL server started successfully, but at the time of login, ERROR 2002 (HY000) appeared: Can 't connect local MySQL server socket, that is, it could not connect to the mysql server through socket and provided the location of the socket file. The following is a description of the problem and the solution.

1. Malfunction

[root@SZDB mysqldata]# mysql -uroot -p123456

Warning: Using a password on the command line interface can be insecure.

ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/data/mysqldata/mysql.sock' (111)

# Fault environment 

[root@SZDB mysqldata]# more /etc/issue

CentOS release 5.9 (Final)

Kernel \r on an \m

2. Fault analysis

# To view mysql State of the instance 

[root@SZDB mysqldata]# netstat -ntlp  | grep 3306

tcp        0      0 :::3306                     :::*                        LISTEN      13001/mysqld

# To view my.cnf about socket The configuration of the 

[root@SZDB mysqldata]# more /etc/my.cnf |grep sock

socket = /tmp/mysql.sock

# By a on the my.cnf Is defined in /tmp Directory, and the error message is /data/mysqldata/ directory 

# That is to say, mysqld It has been claimed to be correct sock File, but the client connection is still found from the original directory sock file 

# Let's look at the background log. There's one ERROR , is about a full query log, and is an error caused by a directory that does not exist, regardless of the current failure 

[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. Troubleshooting

a, by configuring my. cnf mysql option socket file location

# First stop mysql The server 

[root@SZDB mysqldata]# service mysqld stop

Shutting down MySQL.[  OK  ]

# Modify the my.cnf As shown in the following 

[root@SZDB mysqldata]# vi /etc/my.cnf

[mysql]

no-auto-rehash

socket = /tmp/mysql.sock  # Add the bank 

# restart mysql The server 

[root@SZDB mysqldata]# service mysqld start

Starting MySQL..[  OK  ]

# Reconnect normal 

[root@SZDB mysqldata]# mysql -uroot -p

Enter password: 

mysql> show variables like 'version';

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

| Variable_name | Value      |

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

| version       | 5.6.12-log |

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

b. Establish a link for socket file

[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    # The above indicates that the file exists, so delete the previous one mysql.sock file 

[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 |

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