From: Tom Lane <tgl@sss.pgh.pa.us>
To: Kaufhold, Christian (LFD) <Christian.Kaufhold@blfd.bayern.de>
Cc: pgsql-performance@postgresql.org
Subject: Re: Query slow after analyse on postgresql 8.2
Date: Thu, 17 Jun 2010 10:58:36 -0400
Message-ID: <3775.1276786716@sss.pgh.pa.us> (raw)
In-Reply-To: <0694BCCA1B37BE4B8FEB01807799BD540142B47F@BLFD_2.lfd.bayern.de>
References: <0694BCCA1B37BE4B8FEB01807799BD540142B47F@BLFD_2.lfd.bayern.de>
"Kaufhold, Christian (LFD)" <Christian.Kaufhold@blfd.bayern.de> writes:
> I have the following query that I run agains postgresql 8.2:
> ...
> But when I run analyse the same query runs for hours.
Seems like the core of the problem is here:
> -> Seq
> Scan on massnahmeobjekt m (cost=0.00..3271.88 rows=1 width=94) (actual
> time=0.387..577.771 rows=3694 loops=1)
> Filter: ((aktennummer)::text ~* 'M\\-2009\\-1'::text)
If that rowcount estimate weren't off by three orders of magnitude you
probably would be getting a more appropriate plan. The first thing you
could try is increasing the statistics target for aktennummer. Also,
if you're running in a non-C locale and this is 8.2.5 or older, try a
more recent 8.2.x. Updating to 8.3 or 8.4 might help even more.
regards, tom lane
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To: pgsql-performance@postgresql.org
Cc: tgl@sss.pgh.pa.us, Christian.Kaufhold@blfd.bayern.de
Subject: Re: Query slow after analyse on postgresql 8.2
In-Reply-To: <3775.1276786716@sss.pgh.pa.us>
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