Re: Query that uses lots of memory in PostgreSQL 9.2.1 in Windows 7

From: Merlin Moncure <mmoncure(at)gmail(dot)com>
To: Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com>
Cc: Antti Jokipii <anttijokipii(at)gmail(dot)com>, pgsql-performance(at)postgresql(dot)org
Subject: Re: Query that uses lots of memory in PostgreSQL 9.2.1 in Windows 7
Date: 2012-11-27 23:37:34
Message-ID: CAHyXU0yvvBmANx5ohmsGWK5iXT_cpLYf9-ey-iMsatsWJNYPdQ@mail.gmail.com
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On Tue, Nov 20, 2012 at 1:27 AM, Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com> wrote:
> Hello
>
> HashSetOp is memory expensive operation, and should be problematic
> when statistic estimation is bad.
>
> Try to rewritre this query to JOIN

or, 'WHERE NOT EXISTS'. if 41 seconds seems like it's too long, go
ahead and post that plan and maybe that can be optimized.

merlin

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