Re: Postgres performance slowly gets worse over a month

>Nightly, we're doing a 'vacuumdb -a -z' after stopping and restarting
>the database.  The performance will get so bad after a month that we
>start to see load spikes in excess of 30.  Normally, we don't see load
>over 2.5 during the heaviest activity and generally less than 1.0 most
>of the time.
Typically, performance is linked to your I/O, but my first guess in this
case has to do with your indices.  As a test, next time performance gets
really rotten, drop your indicies and rebuild them. It cannot hurt, and
might just help.

The trick here is to see what is happening while it is tanking.  What does
your disk configuration look like?  Is it a raid or stripe where reads are
spread out among more than one controller?  Do sar reports point to
anything in particular?

----------------------------------------------------------------------------
----------------------------------
Naomi Walker
Eldorado Computing, Inc
Chief Information Officer
nwalker@eldocomp.com
602-604-3100 x242