Very high cpu usage/cpu time for mysqld

[Steve Field]

Hello,

I have a site running mysql as the db with Apache using Apache::Session::MySQL to create unique sessions, and DBI for queries to produce dyamic pages.

The site has been running fine on a dual Xeon box for over a year, with very little load on the server.

However, following a recent re-install of the OS (Redhat Enterprise 2.4.21-20.ELsmp), "top" reports 100% cpu usage, and a very high cpu time - 429:46 as of this post for the mysqld process, but nothing has changed apart from the re-install.

I can see no errors in the mysql log, and nothing untoward in the slow query log (a few queries which need to be optimies with times of 16), but mysqld is maxing out and causing the site to run very slowly.

I have checked the "processlist" and it currently shows 38 processes, most of which are in the state "sleep". Some of these processes have times > 100 & some as high as 400.

The site is not receieving any more hits than before the rebuild, so I am at a loss to explain this abnormal load.

Please help!

Thanks

Steve