In the last episode (Mar 09), Mauricio Pellegrini said:
> Hi, I'm trying to tweak the execution time for querys on my mysql
> server which is using InnoDB.
> I know that there are a lot of things to check but one of them,
> perhaps not the most important, is the query_cache_size.
> I have a dual Xeon cpu with 4gb of ram and this is a Linux dedicated
> server which runs only Apache and Mysql 4.1.5
> I've declared Query_cache_size = 16M in the my.cnf file and I would
> say that in the whole we have 60% of select querys and a 40% of
> update querys.
> Is Query_cache_size=16M too conservative considering that I have 4Gb
> of ram ?
A better question is: what is your current utilization of that 16MB
cache? The query cache flushes any results dependant on a table when
that table is modified, so if you really have 40% updates, chances are
that very few queries are cachable at all. Run
show status like 'qcache%';
, and take a look at free_memory, inserts, and hits.