From: Gunnar \"Nick\" Bluth <gunnar.bluth@pro-open.de>
To: Petr Praus <petr@praus.net>
Cc: Marcos Ortiz <mlortiz@uci.cu>
Cc: pgsql-performance@postgresql.org
Subject: Re: Re: Increasing work_mem and shared_buffers on Postgres 9.2 significantly slows down queries
Date: Sat, 03 Nov 2012 18:09:03 +0100
Message-ID: <50954FAF.3060905@pro-open.de> (raw)
In-Reply-To: <CACezXZ9SV58CbFM3-MpKGm1z-J0Ho1zERMUBuLH6QhC7RJ5T8Q@mail.gmail.com>
References: <CACezXZ_w7HbqSxZ=5SJH=kxb4nBDNbpDejttSaU6EC1AeO4PYg@mail.gmail.com>
<CACezXZ_UYbzvNEP_V6-bsyzGij-kJdeNz04-o=kbMXmcLMHnqw@mail.gmail.com>
<5092DE42.5060206@uci.cu>
<509304DC.1090809@pro-open.de>
<CACezXZ-p1UK0K4EJH8b+EBuiD5HY0vNaQvxrnMcjwvjf9cb+oQ@mail.gmail.com>
<5094F280.6010606@pro-open.de>
<CACezXZ9SV58CbFM3-MpKGm1z-J0Ho1zERMUBuLH6QhC7RJ5T8Q@mail.gmail.com>
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.bluth@pro-open.de
__________________________________________________________________________
In 1984 mainstream users were choosing VMS over UNIX. Ten years later
they are choosing Windows over UNIX. What part of that message aren't you
getting? - Tom Payne
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: pgsql-performance@postgresql.org
Cc: gunnar.bluth@pro-open.de, petr@praus.net, mlortiz@uci.cu
Subject: Re: Re: Increasing work_mem and shared_buffers on Postgres 9.2 significantly slows down queries
In-Reply-To: <50954FAF.3060905@pro-open.de>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox