From: Jim C. Nasby <jnasby@pervasive.com>
To: Greg Stark <gsstark@mit.edu>
Cc: Cristian Prieto <cristian@clickdiario.com>
Cc: pgsql-performance@postgresql.org
Subject: Re: Any way to optimize GROUP BY queries?
Date: Tue, 20 Dec 2005 13:47:10 -0600
Message-ID: <20051220194710.GJ28771@pervasive.com> (raw)
In-Reply-To: <87wti0ak60.fsf@stark.xeocode.com>
References: <00d701c604c1$e6945d80$6500a8c0@gt.ClickDiario.local>
<87wti0ak60.fsf@stark.xeocode.com>
On Mon, Dec 19, 2005 at 03:47:35PM -0500, Greg Stark wrote:
> Increase your work_mem (or sort_mem in older postgres versions), you can do
> this for the server as a whole or just for this one session and set it back
> after this one query. You can increase it up until it starts causing swapping
> at which point it would be counter productive.
Just remember that work_memory is per-operation, so it's easy to push
the box into swapping if the workload increases. You didn't say how much
memory you have, but I'd be careful if work_memory * max_connections
gets very much larger than your total memory.
--
Jim C. Nasby, Sr. Engineering Consultant jnasby@pervasive.com
Pervasive Software http://pervasive.com work: 512-231-6117
vcard: http://jim.nasby.net/pervasive.vcf cell: 512-569-9461
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To: pgsql-performance@postgresql.org
Cc: jnasby@pervasive.com, gsstark@mit.edu, cristian@clickdiario.com
Subject: Re: Any way to optimize GROUP BY queries?
In-Reply-To: <20051220194710.GJ28771@pervasive.com>
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