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To: "Craig Ringer" <craig@postnewspapers.com.au>
Cc: "Decibel!" <decibel@decibel.org>,
	"Chris Kratz" <chris.kratz@vistashare.com>,
	<pgsql-performance@postgresql.org>
Subject: Re: Incorrect estimates on correlated filters
In-Reply-To: <48A38ED3.8080500@postnewspapers.com.au> (Craig Ringer's message
	of "Thu\, 14 Aug 2008 09\:48\:03 +0800")
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From: Gregory Stark <stark@enterprisedb.com>
Organization: EnterpriseDB
Date: Thu, 14 Aug 2008 11:12:00 +0100
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"Craig Ringer" <craig@postnewspapers.com.au> writes:

> It strikes me that there are really two types of query hint possible here.
>
> One tells the planner (eg) "prefer a merge join here".
>
> The other gives the planner more information that it might not otherwise
> have to work with, so it can improve its decisions. "The values used in
> this join condition are highly correlated".

This sounds familiar:

http://article.gmane.org/gmane.comp.db.postgresql.devel.general/55730/match=
=3Dhints

Plus =E7a change...

--=20
  Gregory Stark
  EnterpriseDB          http://www.enterprisedb.com
  Ask me about EnterpriseDB's On-Demand Production Tuning