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From: Csaba Nagy <nagy@ecircle-ag.com>
To: Gregory Stark <stark@enterprisedb.com>
Cc: Decibel! <decibel@decibel.org>
Cc: pgsql-performance@postgresql.org
Subject: Re: Linux mis-reporting memory
Date: Fri, 21 Sep 2007 12:08:45 +0200
Message-ID: <1190369325.4661.178.camel@PCD12478> (raw)
In-Reply-To: <87r6ksuzf8.fsf@oxford.xeocode.com>
References: <20070920230400.GM95343@decibel.org>
	<16213.1190329934@sss.pgh.pa.us>
	<87r6ksa1jb.fsf@oxford.xeocode.com>
	<1190363401.4661.116.camel@PCD12478>
	<87r6ksuzf8.fsf@oxford.xeocode.com>

On Fri, 2007-09-21 at 10:43 +0100, Gregory Stark wrote:
> The other possibility is that Postgres just hasn't even touched a large part
> of its shared buffers. 
> 

But then how do you explain the example I gave, with a 5.5GB table
seq-scanned 3 times, shared buffers set to 12 GB, and top still showing
almost 100% memory as cached and no SWAP "used" ? In this case you can't
say postgres didn't touch it's shared buffers - or a sequential scan
won't use the shared buffers ?

Cheers,
Csaba.





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