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

Am 03.11.2012 16:20, schrieb Petr Praus:
>
> 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(dot)bluth(at)pro-open(dot)de
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