From 3bef56e11650a33f70adeb6dd442bc2b48bb9b72 Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Mon, 30 Jan 2023 13:50:25 -0500 Subject: Invent "join domains" to replace the below_outer_join hack. EquivalenceClasses are now understood as applying within a "join domain", which is a set of inner-joined relations (possibly underneath an outer join). We no longer need to treat an EC from below an outer join as a second-class citizen. I have hopes of eventually being able to treat outer-join clauses via EquivalenceClasses, by means of only applying deductions within the EC's join domain. There are still problems in the way of that, though, so for now the reconsider_outer_join_clause logic is still here. I haven't been able to get rid of RestrictInfo.is_pushed_down either, but I wonder if that could be recast using JoinDomains. I had to hack one test case in postgres_fdw.sql to make it still test what it was meant to, because postgres_fdw is inconsistent about how it deals with quals containing non-shippable expressions; see https://postgr.es/m/1691374.1671659838@sss.pgh.pa.us. That should be improved, but I don't think it's within the scope of this patch series. Patch by me; thanks to Richard Guo for review. Discussion: https://postgr.es/m/830269.1656693747@sss.pgh.pa.us --- src/backend/optimizer/plan/createplan.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-) (limited to 'src/backend/optimizer/plan/createplan.c') diff --git a/src/backend/optimizer/plan/createplan.c b/src/backend/optimizer/plan/createplan.c index 4c99b28d0a0..1b118528141 100644 --- a/src/backend/optimizer/plan/createplan.c +++ b/src/backend/optimizer/plan/createplan.c @@ -6210,10 +6210,7 @@ prepare_sort_from_pathkeys(Plan *lefttree, List *pathkeys, * the pathkey's EquivalenceClass. For now, we take the first * tlist item found in the EC. If there's no match, we'll generate * a resjunk entry using the first EC member that is an expression - * in the input's vars. (The non-const restriction only matters - * if the EC is below_outer_join; but if it isn't, it won't - * contain consts anyway, else we'd have discarded the pathkey as - * redundant.) + * in the input's vars. * * XXX if we have a choice, is there any way of figuring out which * might be cheapest to execute? (For example, int4lt is likely -- cgit v1.2.3