check the active connections on the mysql server... a lot of floods goin around lately causing the connections not to close... =\ that's most likely it.
if you have phpmyadmin installed, just click on process.
restarting mysql however will not fix the problem.
if you have to do it via commandline use,
SHOW PROCESSLIST;
http://dev.mysql.com/doc/mysql/en/show-processlist.html