Some error messages from my mailserver

postfix/trivial-rewrite[21090]: warning: mysql query failed: MySQL server has gone away
postfix/trivial-rewrite[21090]: fatal: mysql:/etc/postfix/mysql_virtual_alias_maps.cf(0,lock|fold_fix): table lookup problem
postfix/master[31960]: warning: process /usr/libexec/postfix/trivial-rewrite pid 21090 exit status 1

Spesification :

Slackware 12.0 + postfix + mysql 5.0.x + apache 2.2.x + php

what i've to do :

1. googling

2. check my.cnf

3. change wait_timeout = 60 (work for me, recomended : default falue)

4. restart mysql

5. done.

Reference : 

http://dev.mysql.com/doc/refman/5.1/en/gone-away.html