From: Richard Huxton <dev@archonet.com>
To: Luke Lonergan <LLonergan@greenplum.com>
Cc: albert@sedifa.com
Cc: pgsql-performance@postgresql.org
Subject: Re: Posible planner improvement?
Date: Wed, 21 May 2008 14:09:49 +0100
Message-ID: <48341F1D.3090304@archonet.com> (raw)
In-Reply-To: <014F2941B0A1EA47BD61D21526B806E90162C3D2@MI8NYCMAIL08.Mi8.com>
References: <014F2941B0A1EA47BD61D21526B806E90162C3D2@MI8NYCMAIL08.Mi8.com>
Luke Lonergan wrote:
> The problem is that the implied join predicate is not being
> propagated. This is definitely a planner deficiency.
IIRC only equality conditions are propagated and gt, lt, between aren't.
I seem to remember that the argument given was that the cost of
checking for the ability to propagate was too high for the frequency
when it ocurred.
Of course, what was true for code and machines of 5 years ago might not
be so today.
--
Richard Huxton
Archonet Ltd
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To: pgsql-performance@postgresql.org
Cc: dev@archonet.com, LLonergan@greenplum.com, albert@sedifa.com
Subject: Re: Posible planner improvement?
In-Reply-To: <48341F1D.3090304@archonet.com>
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