Re: GIN indexscans versus equality selectivity estimation - Mailing list pgsql-hackers

From Tom Lane
Subject Re: GIN indexscans versus equality selectivity estimation
Date
Msg-id 3768.1294708159@sss.pgh.pa.us
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In response to Re: GIN indexscans versus equality selectivity estimation  (Josh Berkus <josh@agliodbs.com>)
List pgsql-hackers
Josh Berkus <josh@agliodbs.com> writes:
> 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.

"Implement the other operators"?  I don't think we're on the same page
here.  What I'm talking about is a one-line change in indxpath.c to not
short-circuit consideration of a bitmap indexscan.
        regards, tom lane


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