From: Martin Nickel <martin@portant.com>
To: pgsql-performance@postgresql.org
Subject: Re: shared buffers
Date: Sun, 04 Sep 2005 21:56:01 -0500
Message-ID: <pan.2005.09.05.02.55.50.340618@portant.com> (raw)
References: <20050830015454.54152.qmail@web53204.mail.yahoo.com>
<4313BF95.3030105@familyhealth.com.au>
Chris,
Would you say that 30000 pages is a good maximum for a Postgres install?
We're running 8.0.3 on 64-bit SUSE on a dual Opteron box with 4G and have
shared_buffers set at 120000. I've moved it up and down (it was 160000
when I got here) without any measurable performance difference.
The reason I ask is because I occasionally see large-ish queries take
forever (like cancel-after-12-hours forever) and wondered if this could
result from shared_buffers being too large.
Thanks for your (and anyone else's) help!
Martin Nickel
On Tue, 30 Aug 2005 10:08:21 +0800, Christopher Kings-Lynne wrote:
>> I forgot to say that it´s a 12GB database...
>
> That's actually not that large.
>
>> Ok, I´ll set shared buffers to 30.000 pages but even so "meminfo" and
>> "top" shouldn´t show some shared pages?
>
> Yeah. The reason for not setting buffers so high is because PostgreSQL
> cannot efficiently manage huge shared buffers, so you're better off
> giving the RAM to Linux's disk cache.
>
> Chris
>
>
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To: pgsql-performance@postgresql.org
Cc: martin@portant.com
Subject: Re: shared buffers
In-Reply-To: <pan.2005.09.05.02.55.50.340618@portant.com>
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