diff options
| author | Tom Lane | 2024-05-06 18:22:45 +0000 |
|---|---|---|
| committer | Tom Lane | 2024-05-06 18:22:45 +0000 |
| commit | 07746a8ef2a871d904c26364cdca4e7feeffe395 (patch) | |
| tree | 5399b925676b07c5cd9b5e99e893a72d7d25ad46 | |
| parent | 521a7156ab47623e299855dd04a2a4ea3ad71afe (diff) | |
Finish incomplete revert of ec63622c0.
The code change this made might well be fine to keep, but the
comment justifying it by reference to self-join removal isn't.
Let's just go back to the status quo ante, pending a more thorough
review/redesign of SJE.
(I found this by grepping to see if any references to self-join
removal remained in the tree.)
| -rw-r--r-- | src/backend/optimizer/prep/prepunion.c | 9 |
1 files changed, 3 insertions, 6 deletions
diff --git a/src/backend/optimizer/prep/prepunion.c b/src/backend/optimizer/prep/prepunion.c index 3f14e90a45b..30068c27a13 100644 --- a/src/backend/optimizer/prep/prepunion.c +++ b/src/backend/optimizer/prep/prepunion.c @@ -662,17 +662,14 @@ build_setop_child_paths(PlannerInfo *root, RelOptInfo *rel, * otherwise do statistical estimation. * * XXX you don't really want to know about this: we do the estimation - * using the subroot->parse's original targetlist expressions, not the + * using the subquery's original targetlist expressions, not the * subroot->processed_tlist which might seem more appropriate. The reason * is that if the subquery is itself a setop, it may return a * processed_tlist containing "varno 0" Vars generated by * generate_append_tlist, and those would confuse estimate_num_groups * mightily. We ought to get rid of the "varno 0" hack, but that requires * a redesign of the parsetree representation of setops, so that there can - * be an RTE corresponding to each setop's output. Note, we use this not - * subquery's targetlist but subroot->parse's targetlist, because it was - * revised by self-join removal. subquery's targetlist might contain the - * references to the removed relids. + * be an RTE corresponding to each setop's output. */ if (pNumGroups) { @@ -685,7 +682,7 @@ build_setop_child_paths(PlannerInfo *root, RelOptInfo *rel, *pNumGroups = rel->cheapest_total_path->rows; else *pNumGroups = estimate_num_groups(subroot, - get_tlist_exprs(subroot->parse->targetList, false), + get_tlist_exprs(subquery->targetList, false), rel->cheapest_total_path->rows, NULL, NULL); |