From: Richard Huxton <dev@archonet.com>
To: SURANTYN Jean Fran+AOc-ois <jfsurant@supermarchesmatch.fr>
Cc: pgsql-performance@postgresql.org
Subject: Re: Optimizer : query rewrite and execution plan ?
Date: Wed, 06 Feb 2008 10:06:47 +0000
Message-ID: <47A986B7.3000809@archonet.com> (raw)
In-Reply-To: <60F4687513E90748AE8933DEA5D054E79ACBE5@SLAM0018.match-supermarket.com>
References: <60F4687513E90748AE8933DEA5D054E79ACBE5@SLAM0018.match-supermarket.com>
SURANTYN Jean Fran+AOc-ois wrote:
> Many thanks for your quick reply
>
> In fact, that issue comes from a recent migration from Oracle to
> Postgresql, and even if some queries were not optimized by the past
> (example: where n=1 and n=1), Oracle was able to rewrite them and to
> "hide" the bad queries". But now that we have migrated to Postgresql,
> we have discovered that some queries were indeed badly wroten I will
> tell to the developpers to try to optimize their queries for them to
> work efficiently on Postgresql
If nothing else it will help when / if you decide to use prepared
queries - there's no way to optimise "n=+ACQ-1 or n=+ACQ-2" at planning time.
--
Richard Huxton
Archonet Ltd
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To: pgsql-performance@postgresql.org
Cc: dev@archonet.com, jfsurant@supermarchesmatch.fr
Subject: Re: Optimizer : query rewrite and execution plan ?
In-Reply-To: <47A986B7.3000809@archonet.com>
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