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Re: Join Query Perfomance Issue

From: "Scott Marlowe" <scott(dot)marlowe(at)gmail(dot)com>
To: "Thomas Zaksek" <zaksek(at)ptt(dot)uni-due(dot)de>
Cc: pgsql-performance(at)postgresql(dot)org
Subject: Re: Join Query Perfomance Issue
Date: 2008-02-13 21:36:07
Message-ID: dcc563d10802131336s366d66c6kcb9f1fd23818552b@mail.gmail.com (view raw or flat)
Thread:
Lists: pgsql-performance
On Feb 12, 2008 4:11 AM, Thomas Zaksek <zaksek(at)ptt(dot)uni-due(dot)de> wrote:

> I tried turning off nestloop, but with terrible results:

Yeah, it didn't help.  I was expecting the query planner to switch to
a more efficient join plan.

> I also tried to increase work_men, now the config is
> work_mem = 4MB

Try setting it higher for JUST THIS query.  i.e.

set work_mem=128M;
explain analyze select ....

and see how that runs.  Then play with it til you've got it down to
what helps.  Note that work_mem in postgresql.conf being too large can
be dangerous, so it might be something you set for just this query for
safety reasons.

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