Re: PATCH: index-only scans with partial indexes - Mailing list pgsql-hackers

From Kyotaro HORIGUCHI
Subject Re: PATCH: index-only scans with partial indexes
Date
Msg-id 20150918.104610.199079215.horiguchi.kyotaro@lab.ntt.co.jp
Whole thread Raw
In response to Re: PATCH: index-only scans with partial indexes  (Tomas Vondra <tomas.vondra@2ndquadrant.com>)
Responses Re: PATCH: index-only scans with partial indexes  (Tomas Vondra <tomas.vondra@2ndquadrant.com>)
List pgsql-hackers
Hello,

At Thu, 17 Sep 2015 17:40:27 +0200, Tomas Vondra <tomas.vondra@2ndquadrant.com> wrote in
<55FADEEB.4000907@2ndquadrant.com>
> Yes, this seems sane. I've been poking at this a bit too, and I came
> to the same plan in general, except that I think it's better to build
> list of clauses that are *not* implied by the index, because that's
> what we need both in cost_index and check_index_only.

I intended to isolate IndexOptInfo from belonging RelOptInfo but
the exclusion list also bonds them tightly, and one IndexOptInfo
belongs to only one RelOptInfo so no need to isolate. So
not-implied-restrictclauses in IndexOptInfo would be preferable.

> It also seems to me that this change (arguably a bug fix) should
> pretty much make the original patch irrelevant, because
> check_index_only can simply walk over the new list.

Yeah. This seems to be a bug irrelevant to your index-only-scan
ptch.

regards,

-- 
Kyotaro Horiguchi
NTT Open Source Software Center




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