Comments on: MySQL Tuning: Disable Query Cache on Frequently Updated Databases

By: Tuning and Optimizing Performace of MySQL | lonerunners.net

Tuning and Optimizing Performace of MySQL | lonerunners.net — Sun, 02 Nov 2008 00:35:48 +0000

[...] MySQL Tuning: Disable Query Cache on Frequently Updated Databases [...]

By: Dan

Dan — Sun, 29 Apr 2007 01:26:43 +0000

The setting for on demand is:
query_cache_type = 2

Then you’d add the SQL_CACHE hint to the SELECT queries to have them cached:
SELECT SQL_CACHE [columns] FROM [table] …

By: Chemist

Chemist — Sun, 29 Apr 2007 00:44:43 +0000

So in my.cnf I would add:

query_cache_type on demand

But how do you specify the queries to cache?

By: Dan

Dan — Thu, 26 Apr 2007 23:03:28 +0000

You may be able to do that if you change the query cache type to “on demand” and explicitly tell it which SELECT queries you want cached. Otherwise, my fear is SELECT queries against those other tables might knock longer-lasting SELECTs out of the smaller cache before being quickly removed themselves. In either scenario here, there’s still overhead attached to the UPDATE and INSERT queries checking if they invalidate something in the cache. Only turning off the cache removes that overhead entirely.

By: Seun Osewa

Seun Osewa — Thu, 26 Apr 2007 22:55:05 +0000

How about just reducing the size of the query cache so the small queries on less frequently updated tables will remain in the cache?