MySQL Bugs: #42182: MySQL Sleep proceses when query_cache

Bug #42182	MySQL Sleep proceses when query_cache_type=1
Submitted:	17 Jan 2009 21:49	Modified:	19 Jan 2009 10:38
Reporter:	Ryan Barclay	Email Updates:
Status:	Unsupported	Impact on me:	None
Category:	MySQL Server: Query Cache	Severity:	S2 (Serious)
Version:	4.0.23-standard	OS:	Linux (FC2)
Assigned to:		CPU Architecture:	Any
Tags:	cache, Process, processes, query, sleep

Description:
I have been getting some sleeping processes that fail to end until the wait_timeout kills them.  

This happens only when I enable the query cache with query_cache_type=1.  This also proves it's not a problem with the PHP script, because it only happens when the query cache is turned on.  Can anyone shed any light onto this issue?

How to repeat:
set query_cache_type=1 in my.cnf

Any ideas anyone?  Is there a fix for this bug?

Thank you for a problem report. Please, try to repeat with a newer version of 4.0.x. In case of the same problem, please, send SHOW PROCESSLIST results with these "sleep processes" and your my.cnf file content.

It's a live server with some high traffic sites using the database, upgrading won't be an option.  Is there anything I can do without this?

Thank you for taking the time to report a problem.  Unfortunately you are not using a current version of the product you reported a problem with -- the problem might already be fixed. Please download a new version from http://www.mysql.com/downloads/

If you are able to reproduce the bug with one of the latest versions, please change the version on this bug report to the version you tested and change the status back to "Open".  Again, thank you for your continued support of MySQL.

Extended support for version 4.0 ended at Dec 31, 2008 (http://www.mysql.com/about/legal/lifecycle/#calendar) Please use current GA version 5.1.