Re: Docs about buffers and sortmem setting

From: "scott(dot)marlowe" <scott(dot)marlowe(at)ihs(dot)com>
To: Bjoern Metzdorf <bm(at)turtle-entertainment(dot)de>
Cc: <pgsql-performance(at)postgresql(dot)org>
Subject: Re: Docs about buffers and sortmem setting
Date: 2002-11-14 19:27:42
Message-ID: Pine.LNX.4.33.0211141226350.1891-100000@css120.ihs.com
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On Thu, 14 Nov 2002, Bjoern Metzdorf wrote:

> > The general rule of thumb is to try about 25% of physical memory for
> > your buffer size. Some people like to increase from there, until
> > swapping starts, and then back off; but there are arguments against
> > doing this, given the efficiency of modern filesystem buffering.
>
> How about 32-bit Linux machines with more than 1 GB RAM? We have a 2 GB RAM
> machine running, and I gave 800 MB to postgres shared buffers. AFAIK Linux
> user space can handle only 1 GB and the rest is for kernel buffer and
> cache..

Actually, I think the limit is 2 or 3 gig depending on how your kernel was
compiled, but testing by folks on the list seems to show a maximum of
under 2 gig. I'm a little fuzzy on it, you might wanna search the
archives. I'm not sure if that was a linux or a postgresql problem, and
it was reported several months back.

Memory slowly fading.... :-)

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