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Message-ID: <4C3441EB.8010405@gmail.com>
Date: Wed, 07 Jul 2010 10:59:23 +0200
From: Yeb Havinga <yebhavinga@gmail.com>
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To: "JOUANIN Nicolas (44)" <nicolas.jouanin@dgfip.finances.gouv.fr>
CC: pgsql-performance@postgresql.org
Subject: Re: Two different execution plan for the same request
References: <4C3432F0.1090004@dgfip.finances.gouv.fr>
	<4C343A59.7050908@gmail.com>
	<4C343F31.2050402@dgfip.finances.gouv.fr>
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JOUANIN Nicolas (44) wrote:
>
> The strange thing is that this morning explain analyze now gives a 
> much better duration :
>
> There were no modification made on the database except a restart 
> yesterday evening and a vacuumdb --analyse ran at night.
If the earlier bad query was run on a fresh imported database that was 
not ANALYZEd, it would explain the different and likely bad plan. If you 
want to know for sure this is the cause, instead of e.g. faulty 
hardware, you could verify redoing the import + query without analyze.

regards,
Yeb Havinga