Re: slow query

From: Oleg Lebedev <oleg(dot)lebedev(at)waterford(dot)org>
To: Robert Treat <xzilla(at)users(dot)sourceforge(dot)net>
Cc: "pgsql-performance(at)postgresql(dot)org" <pgsql-performance(at)postgresql(dot)org>
Subject: Re: slow query
Date: 2003-02-24 17:07:03
Message-ID: 993DBE5B4D02194382EC8DF8554A5273113DF3@postoffice.waterford.org
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I run VACUUM (not FULL though) every night, which I thought would be
enough for good query performance. Moreover, the data in table does not
really change significantly since database usage is pretty low right
now, therefore I thought that VACUUM FULL was an overkill.
I think that creating, populating and dropping schemas in the master
database could have affected the query performance and required VACUUM
FULL.
I will definitely look at max_fsm_relations and max_fsm_pages parameter
settings.
Thank you.

Oleg Lebedev

-----Original Message-----
From: Robert Treat [mailto:xzilla(at)users(dot)sourceforge(dot)net]
Sent: Monday, February 24, 2003 9:59 AM
To: Oleg Lebedev
Cc: Josh Berkus; pgsql-performance(at)postgresql(dot)org
Subject: Re: [PERFORM] slow query

On Mon, 2003-02-24 at 10:59, Oleg Lebedev wrote:
> Thanks everybody for your help.
> VACUUM FULL did the job, and now the query performance is the same in
> both databases. I am surprised that FULL option makes such a dramatic
> change to the query performance: from 4min. to 5sec.!!! It also
> changed planner stats from ~9 sec to ~8sec.

If your seeing wildly dramatic improvments from vacuum full, you might
want to look into running regular vacuums more often (especially for
high turnover tables), increase your max_fsm_relations to 1000, and
increasing your max_fsm_pages.

Robert Treat

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