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| author | Tom Lane <tgl@sss.pgh.pa.us> | 2022-08-17 15:35:51 -0400 |
|---|---|---|
| committer | Tom Lane <tgl@sss.pgh.pa.us> | 2022-08-17 15:35:51 -0400 |
| commit | 6569ca43973b754e8213072c8ddcae9e7baf2aaa (patch) | |
| tree | 396627f9ae41b4bd5f069cd20c142d30d62b8b59 /src/backend/optimizer/plan/analyzejoins.c | |
| parent | efd0c16becbf45e3b0215e124fde75fee8fcbce4 (diff) | |
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
Diffstat (limited to 'src/backend/optimizer/plan/analyzejoins.c')
| -rw-r--r-- | src/backend/optimizer/plan/analyzejoins.c | 3 |
1 files changed, 3 insertions, 0 deletions
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); |