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Re: Posible planner improvement?

From: Albert Cervera Areny <albert(at)sedifa(dot)com>
To: pgsql-performance(at)postgresql(dot)org
Subject: Re: Posible planner improvement?
Date: 2008-05-21 16:22:42
Message-ID: 200805211822.42528.albert@sedifa.com (view raw or flat)
Thread:
Lists: pgsql-hackerspgsql-performance
A Dimecres 21 Maig 2008, Richard Huxton va escriure:
> 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.

Hope this can be revisited given the huge difference in this case: 80 minutes 
to 1 second.

-- 
Albert Cervera Areny
Dept. Informàtica Sedifa, S.L.

Av. Can Bordoll, 149
08202 - Sabadell (Barcelona)
Tel. 93 715 51 11
Fax. 93 715 51 12

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