MySQL Bugs: #65541: Partitioning + Query Cache

Bug #65541	Partitioning + Query Cache
Submitted:	6 Jun 2012 18:05	Modified:	12 Jul 2012 2:03
Reporter:	Todd Wade	Email Updates:
Status:	Duplicate	Impact on me:	None
Category:	MySQL Server: Documentation	Severity:	S3 (Non-critical)
Version:	5.1, 5.5, 5.6	OS:	Any
Assigned to:	Jon Stephens	CPU Architecture:	Any
Tags:	partitioning, query cache

Description:
Spent quite a bit of time examining partitioning and porting my app to partitions, only to find out my queries weren't being cached in the query cache. After searching around I found the cache was disabled for http://bugs.mysql.com/bug.php?id=53775

I think this is a huge limitation and should be listed at http://dev.mysql.com/doc/refman/5.6/en/partitioning-limitations.html

http://dev.mysql.com/doc/refman/5.5/en/query-cache-operation.html should probably be updated too

Also it would be nice to actually get query caching on queries to partitioned tables.

How to repeat:
Assume your query cache will still work after porting to partitions.

Thank you for the report.

Bug #53775 has been fixed. Which exact version do you use?

> Bug #53775 has been fixed.

I wouldn't call it 'fixed' The query cache was disabled. I'm unable to use the query cache as it is documented.

It should be stated prominently on the partitioning limitations page (http://dev.mysql.com/doc/refman/5.6/en/partitioning-limitations.html) that you can not use the query cache with a partitioned table.

Thank you for the feedback.

I was confused by comment:

----<q>----
[8 Jul 2010 12:59] Mikael Ronstrom

Disabling the query cache for partitioned tables
is a bit too harsh of a solution.
----</q>----

But after checking actual patch found you are correct. This must be documented, of course.

A documentation bug, verified for a month, not set to Server: Documentation, not assigned?

Kolbe,

I've fixed category now and added all versions actually affected. 

The bug was already copied to Oracle's internal BugDB few days ago and assigned to docs. team.

Duplicate of BUG#53775.

[11 Jul 17:11] Jon Stephens
> Duplicate of BUG#53775.

Hi Jon,

I wouldn't call this bug a duplicate of 53775. In 53775, the query cache was disabled for partitioned tables. So be it.

This bug that I've filed is a documentation bug. This should be pretty clear by reading my original submission:

> I think this is a huge limitation and should be listed at http://dev.mysql.com/doc/refman/5.6/en/partitioning-limitations.html
>
> http://dev.mysql.com/doc/refman/5.5/en/query-cache-operation.html should probably be updated too

Thank you,

Todd,

The issue lay in the fact that the original bug report was not documented/closed correctly. If you view BUG#53775, you can see that this has been taken care of. 

There is no new *issue* here; thus, opening a new bug report is simply multiplying bug reports (and their attendant overhead) without need.