Re: PATCH: index-only scans with partial indexes

Hello,

At Thu, 17 Sep 2015 17:40:27 +0200, Tomas Vondra <tomas(dot)vondra(at)2ndquadrant(dot)com> wrote in <55FADEEB(dot)4000907(at)2ndquadrant(dot)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