From: Bill Moran <wmoran@collaborativefusion.com>
To: Campbell, Lance <lance@uiuc.edu>
Cc: pgsql-performance@postgresql.org
Subject: Re: work_mem and shared_buffers
Date: Fri, 9 Nov 2007 15:08:09 -0500
Message-ID: <20071109150809.e75af5b3.wmoran@collaborativefusion.com> (raw)
In-Reply-To: <B10E6810AC2A2F4EA7550D072CDE8760197DE5@SAB-FENWICK.sab.uiuc.edu>
References: <B10E6810AC2A2F4EA7550D072CDE8760197DE4@SAB-FENWICK.sab.uiuc.edu>
<47349F4E.5070204@enterprisedb.com>
<B10E6810AC2A2F4EA7550D072CDE8760197DE5@SAB-FENWICK.sab.uiuc.edu>
On Fri, 9 Nov 2007 12:08:57 -0600
"Campbell, Lance" <lance@uiuc.edu> wrote:
> How do you know when you should up the value of work_mem? Just play
> with the number. Is there a query I could do that would tell me if
> PostgreSql is performing SQL that could use more memory for sorting?
8.2 and older, it can be difficult to know, and I don't have a specific
recommendation.
8.3 includes a parameter to log the usage of temporary files by Postgres.
When a sort can't fit in the available memory, it uses a temp file, thus
you could use this new feature to track when sorts don't fit in
work_mem.
--
Bill Moran
Potential Technologies
http://www.potentialtech.com
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To: pgsql-performance@postgresql.org
Cc: wmoran@collaborativefusion.com, lance@uiuc.edu
Subject: Re: work_mem and shared_buffers
In-Reply-To: <20071109150809.e75af5b3.wmoran@collaborativefusion.com>
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