Message-Id: <5.1.0.14.2.20010711151558.00ac0590@pop.planetcable.net>
Date: Wed, 11 Jul 2001 16:42:16 -0400
To: pgsql-general@postgresql.org
From: Adam Manock <abmanock@planetcable.net>
Subject: Re: Performance tuning for linux, 1GB RAM, dual CPU? 
In-Reply-To: <23761.994870319@sss.pgh.pa.us>
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	<5146853DD571D411AC54000102070D611C7F10@MINGBGNTS02>
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 >This is almost certainly a lousy idea.  You do *not* want to chew up all
 >available memory for PG shared buffers; you should leave a good deal of
 >space for kernel-level disk buffers.

I decided to start high on buffers because of Bruce's:
	http://www.ca.postgresql.org/docs/hw_performance/
 From that I get the impression that operations using kernel disk buffer
cache are considerably more expensive than if the data was in shared
buffer cache, and that increasing PG's memory usage until the system
is almost using swap is The Right Thing To Do.  Has anyone got real
world test data to confirm or refute this??
    If not, then I am going to need to find or create a benchmarking program
to load down PG against a fake multi-gigabyte "production" database.
Or I could wait a week to see what RedHat does to tune their
implementation of PG :-)

Adam