Re: PostgreSQL performance question.

> I have been using PostgreSQL (currently 7.4.7) for several years now and 
> am very happy with it but I currently run a website that has had a 
> little bit of a boost and I am starting to see some performance problems 
> (Not necessarily PostgreSQL).

PostgreSQL 8.1.1 should give you greater performance...

> The database has been allocated 2Gb worth of shared buffers and I have 
> tweaked most of the settings in the config recently to see if I could 
> increase the performance any more and have seen very little performance 
> gain for the various types of queries that I am running.

That sounds like far too many shared buffers?  I wouldn't usually use 
more than a few tens of thousands, eg. 10k-50k.  And that'd only be on 
8.1 that has more efficient buffer management.

> Get it into RAM hence the slight delay here. This delay has a serious 
> impact on the user waiting in the web application.
> 
> # select * from test where text = 'uk' ;
> Time: 477.739 ms

You need to show us the explain analyze plan output for this.  But 477ms 
is far too slow for an index scan on a million row table.

> max_fsm_pages = 500000 # I am thinking this might be a bit low.
> max_fsm_relations = 1000

Maybe do a once-off vacuum full to make sure all your tables are clean?

Chris