Re: Re: Increasing work_mem and shared_buffers on Postgres 9.2 significantly slows down queries

Your CPUs are indeed pretty oldschool. FSB based, IIRC, not NUMA. A process migration would be even more expensive there.

Ok, I've actually looked these up now... at the time these were current, I was in the lucky situation to only deal with Opterons. And actually, with these CPUs it is pretty possible that Scott Marlowe's hint (check vm.zone_reclaim_mode) was pointing in the right direction. Did you check that?

Yes, same behaviour. I let the shared_buffers be the default (which is 8MB). With work_mem 1MB the query runs fast, with 96MB it runs slow (same times as before). It really seems that the culprit is work_mem.

Well, I'm pretty sure that having more work_mem is a good thing (tm) normally ;-)

-- 
Gunnar "Nick" Bluth
RHCE/SCLA

Mobil   +49 172 8853339
Email: gunnar.bluth@pro-open.de
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