| From: | "Jim C(dot) Nasby" <jnasby(at)pervasive(dot)com> |
|---|---|
| To: | Greg Stark <gsstark(at)mit(dot)edu> |
| Cc: | Cristian Prieto <cristian(at)clickdiario(dot)com>, pgsql-performance(at)postgresql(dot)org |
| Subject: | Re: Any way to optimize GROUP BY queries? |
| Date: | 2005-12-20 19:47:10 |
| Message-ID: | 20051220194710.GJ28771@pervasive.com |
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| Thread: | |
| Lists: | pgsql-performance |
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(at)pervasive(dot)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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