Re: postgresql performance degradation over time....

On Sat, Aug 27, 2005 at 18:19:54 +0530,
sunil arora <arora(dot)sunil(at)gmail(dot)com> wrote:
> Bruno,
> thanks for the reply,
> we did run vaccum on it.. and we do it regulary to maintain its
> performance but its not giving the expected results.

Did you do VACUUM FULL or just plain VACUUM?

> I dont know but if we delete the entire database and restore it with
> the dump, then things seems to improve a _LOT_.
> Isnt vaccum suppose to do the same task for us ??
> what could be going any idea ??

It sounds like you have a lot of dead tuples or index bloat. I think 7.4
had the main index bloat issue fixed, but I think that it was still possible
to get bloated indexes in some circumstances. So it might be worth trying
to reindex the tables.

Note that plain VACUUM only does the job it is supposed to if your FSM
setting is large enough to handle all of the dead tuples in a table. It
also doesn't move valid tuples around to allow the underlying files to
be reduced to the minimum size needed. If things have gotten bad enough
you want to do a VACUUM full. (Cluster can be a faster way to do this,
but for only a couple of Gigs of data, it may not be worth the trouble.)