Message-ID: <47A986B7.3000809@archonet.com>
Date: Wed, 06 Feb 2008 10:06:47 +0000
From: Richard Huxton <dev@archonet.com>
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	<jfsurant@supermarchesmatch.fr>
CC: pgsql-performance@postgresql.org
Subject: Re: Optimizer : query rewrite and execution plan ?
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SURANTYN Jean Fran+AOc-ois wrote:
> Many thanks for your quick reply
>=20
> 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=3D1 and n=3D1), Oracle was able to rewrite them and t=
o
> "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=3D+ACQ-1 or n=3D+ACQ-2" at planni=
ng time.

--=20
  Richard Huxton
  Archonet Ltd