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

From Josh Berkus
Subject Re: GIN indexscans versus equality selectivity estimation
Date
Msg-id 4D2B4A15.3010106@agliodbs.com
Whole thread Raw
In response to Re: GIN indexscans versus equality selectivity estimation  (Tom Lane <tgl@sss.pgh.pa.us>)
Responses Re: GIN indexscans versus equality selectivity estimation  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
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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