Re: GIN indexscans versus equality selectivity estimation

From: Robert Haas <robertmhaas(at)gmail(dot)com>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: pgsql-hackers(at)postgresql(dot)org
Subject: Re: GIN indexscans versus equality selectivity estimation
Date: 2011-01-10 01:35:41
Message-ID: AANLkTi=zfnByKu_D7g1aJJ=P4f=_zLU8f9Zjor=Qrew-@mail.gmail.com
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On Sun, Jan 9, 2011 at 6:38 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> or we could hack eqsel() to bound the no-stats estimate to a bit less
> than 1.

This seems like a pretty sensible thing to do. I can't immediately
imagine a situation in which 1.0 is a sensible selectivity estimate in
the no-stats case and 0.90 (say) is a major regression.

--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company

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