Getting this error? Can't connect to local MySQL server through socket '/tmp/mysql.sock' (2)
Check if there is a mysql.sock file at /var/lib/mysql/mysql.sock (rather than in /tmp).
If so, change /etc/php.ini from:
mysql.default_socket = /var/lib/mysql/mysql.sock
And restart httpd.
TODO: This problem has cropped up on a 'previously working setup' (not one of mine). So I'm not sure why there is a change from /tmp to /var/lib/mysql. New version of mysql? New version of php?