A frequent error message received when using the mysql command line utility is: Can’t connect to local MySQL server through socket ‘/tmp/mysql.sock’ While this error message can be frustrating, the solution is simple.
When connecting to a MySQL server located on the local system, the mysql client connects thorugh a local file called a socket instead of connecting to the localhost loopback address 127.0.0.1. For the mysql client, the default location of this socket file is /tmp/mysql.sock. However, for a variety of reasons, many MySQL installations place this socket file somewhere else like /var/lib/mysql/mysql.sock.
While it is possible to make this work by specifying the socket file directly in the mysql client command
mysql –socket=/var/lib/mysql/mysql.sock …
it is painful to type this in every time. If you must do so this way (because you don’t have permissions to the file in the solution below), you could create an alias in your shell to make this work (like alias mysql=”mysql –socket=/var/lib/mysql/mysql.sock” depending on your shell).
To make your life easier, you can make a simple change to the MySQL configuration file /etc/my.cnf that will permanently set the socket file used by the mysql client. After making a backup copy of /etc/my.cnf, open it in your favorite editor. The file is divided into sections such as
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:
If there is already a [client] section in the my.cnf file, add or edit the socket line as appropriate. You won’t need to restart your server or any other processes. Subsequent uses of the mysql client will use the proper socket file.
Extrapolating this to my case, i moved the MySQL database to another hard-drive, so the client would still connect to the old .sock file, so i defined the CLIENT section in /etc/my.cnf.
Also, i had to change in php.ini the default mysql_connect socket, to point to the new location.
In case you’re using MailScanner, it has to be restarted as well, because it will still try to use the old mysql socket.