From: Cédric Villemain <cedric.villemain@dalibo.com>
To: Bill Moran <wmoran@collaborativefusion.com>
Cc: Campbell, Lance <lance@uiuc.edu>
Cc: pgsql-performance@postgresql.org
Subject: Re: work_mem and shared_buffers
Date: Mon, 12 Nov 2007 11:17:57 +0100
Message-ID: <47382855.1090902@dalibo.com> (raw)
In-Reply-To: <20071109150809.e75af5b3.wmoran@collaborativefusion.com>
References: <B10E6810AC2A2F4EA7550D072CDE8760197DE4@SAB-FENWICK.sab.uiuc.edu>
<47349F4E.5070204@enterprisedb.com>
<B10E6810AC2A2F4EA7550D072CDE8760197DE5@SAB-FENWICK.sab.uiuc.edu>
<20071109150809.e75af5b3.wmoran@collaborativefusion.com>
Bill Moran a écrit :
> 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.
>
>
I haven't use it in that context before, but perhaps inotify can be used
to catch postgresql usage of temp files. ( http://inotify.aiken.cz/ ,
http://inotify.aiken.cz/?section=incron&page=about&lang=en )
> 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.
>
>
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To: pgsql-performance@postgresql.org
Cc: cedric.villemain@dalibo.com, wmoran@collaborativefusion.com, lance@uiuc.edu
Subject: Re: work_mem and shared_buffers
In-Reply-To: <47382855.1090902@dalibo.com>
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