Re: PATCH: index-only scans with partial indexes

I marked this as "ready for commiter" and tried to add me as the
*second* author. But the CF app forces certain msyterious order
for listed names. Is there any means to arrange the author names
in desired order?

At Fri, 26 Feb 2016 16:06:37 +0900 (Tokyo Standard Time), Kyotaro HORIGUCHI <horiguchi(dot)kyotaro(at)lab(dot)ntt(dot)co(dot)jp> wrote in <20160226(dot)160637(dot)65689630(dot)horiguchi(dot)kyotaro(at)lab(dot)ntt(dot)co(dot)jp>
> Hello, This is a (maybe) committer-ready patch of a Tomas
> Vondra's project.
>
> This patch applies on the current master and passes make check.
>
> This is to exclude some base-estrict clauses that are implied by
> index predicates on index scans on partial indexes.
>
> First, this patch adds a new member indexrinfos to IndexOptInfo,
> which usually has the same value with baserestrictinfo of the
> parent RelOptInfo and cost_index() uses this instead of
> RelOptInfo.baserestrictinfo.
>
> For partial indexes, the clauses implied by the index predicates
> are removed from the indexrinfos, so that the result plan for
> scans on such indexes won't contain such restrictions. Such
> restrictions commonly become filter quals that are nothing but a
> useless work to do, so this will improve the performance of some
> index scans on partial indexes.
>
> The largest part of the extra cost of the additional work would
> be the cost of predicate_implied_by() on all clauses of
> baserectrictinfo and indpred of every IndexOptInfos. The extra
> work is done in check_partial_indexes() for all index scans on
> partial indexes.

--
Kyotaro Horiguchi
NTT Open Source Software Center