From 6569ca43973b754e8213072c8ddcae9e7baf2aaa Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Wed, 17 Aug 2022 15:35:51 -0400 Subject: Make PlaceHolderInfo lookup O(1). Up to now we've just searched the placeholder_list when we want to find the PlaceHolderInfo with a given ID. While there's no evidence of that being a problem in the field, an upcoming patch will add find_placeholder_info() calls in build_joinrel_tlist(), which seems likely to make it more of an issue: a joinrel emitting lots of PlaceHolderVars would incur O(N^2) cost, and we might be building a lot of joinrels in complex queries. Hence, add an array that can be indexed directly by phid to make the lookups constant-time. Discussion: https://postgr.es/m/1405792.1660677844@sss.pgh.pa.us --- src/backend/optimizer/plan/analyzejoins.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'src/backend/optimizer/plan/analyzejoins.c') diff --git a/src/backend/optimizer/plan/analyzejoins.c b/src/backend/optimizer/plan/analyzejoins.c index 337f470d583..bbeca9a9abe 100644 --- a/src/backend/optimizer/plan/analyzejoins.c +++ b/src/backend/optimizer/plan/analyzejoins.c @@ -388,8 +388,11 @@ remove_rel_from_query(PlannerInfo *root, int relid, Relids joinrelids) Assert(!bms_is_member(relid, phinfo->ph_lateral)); if (bms_is_subset(phinfo->ph_needed, joinrelids) && bms_is_member(relid, phinfo->ph_eval_at)) + { root->placeholder_list = foreach_delete_current(root->placeholder_list, l); + root->placeholder_array[phinfo->phid] = NULL; + } else { phinfo->ph_eval_at = bms_del_member(phinfo->ph_eval_at, relid); -- cgit v1.2.3