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From: Greg Smith <gsmith@gregsmith.com>
To: pgsql-performance@postgresql.org
Subject: Re: Question about memory allocations
Date: Thu, 12 Apr 2007 22:50:08 -0400 (EDT)
Message-ID: <Pine.GSO.4.64.0704122238580.29657@westnet.com> (raw)
In-Reply-To: <Pine.GSO.4.64.0704101458290.17955@kittyhawk.tanabi.org>
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	<26925.1176221294@sss.pgh.pa.us>
	<Pine.GSO.4.64.0704101458290.17955@kittyhawk.tanabi.org>

On Tue, 10 Apr 2007, Steve wrote:

> - I've set up a configuration (I'll show important values below), and I"m 
> wondering if there's any way I can actually see the distribution of memory in 
> the DB and how the memory is being used.

I didn't notice anyone address this for you yet.  There is a tool in 
contrib/pg_buffercache whose purpose in life is to show you what the 
shared buffer cache has inside it.  The documentation in that directory 
leads through installing it.  The additional variable you'll likely never 
know is what additional information is inside the operating system's 
buffer cache.

> # Leaving this low makes the DB complain, but I'm not sure what's # 
> reasonable.
> checkpoint_segments = 128

That's a reasonable setting for a large server.  The main downside to 
setting it that high is longer recovery periods after a crash, but I doubt 
that's a problem for you if you're so brazen as to turn off fsync.

--
* Greg Smith gsmith@gregsmith.com http://www.gregsmith.com Baltimore, MD



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