Re: GIN indexscans versus equality selectivity estimation

From: Josh Berkus <josh(at)agliodbs(dot)com>
To: pgsql-hackers(at)postgresql(dot)org
Subject: Re: GIN indexscans versus equality selectivity estimation
Date: 2011-01-10 18:04:05
Message-ID: 4D2B4A15.3010106@agliodbs.com
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On 1/10/11 7:25 AM, Tom Lane wrote:
> I'm a bit worried though that there might be other
> cases where the estimator comes up with 1.0 selectivity but it'd still
> be worth considering a bitmap scan.

Well, I think the answer is to apply the other fixes, and test. If
there are other cases of selectivity=1.0, they'll show up. People are
pretty fast to complain if indexes aren't used, and we have a good
production test case available once you implement the other operators.

--
-- Josh Berkus
PostgreSQL Experts Inc.
http://www.pgexperts.com

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