>If I understand you correctly, this means that the 2GB cache is being scanned all the time. For test purpposes, is there a way to specify "no cache" on these 2 queries or tables to make sure there is no cache scan happening then ?
As I said before your query_cache is too big, you can monitor query cache performance i.e. SHOW GLOBAL STATUS LIKE 'Qc%' to determine such as how much free space is available, cache hits etc. Note, query cache has got scalability issues.
You can use 'SQL_NO_CACHE', e.g.
SELECT SQL_NO_CACHE COUNT(id) FROM jos_content, jos_ijoomla.....
Similarly you can change query_cache_type=2 # on DEMAND,
http://dev.mysql.com/doc/refman/5.1/en/server-system-variables.html#sysvar_query_cache_type
http://dev.mysql.com/doc/refman/5.0/en/query-cache-in-select.html
Edited 1 time(s). Last edit at 07/12/2012 07:07AM by Aftab Khan.