From 6f44fe7f121ac7c29c1ac8553e4e209f9c3bfbcb Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Sun, 17 Sep 2017 15:28:51 -0400 Subject: [PATCH] Allow rel_is_distinct_for() to look through RelabelType below OpExpr. This lets it do the right thing for, eg, varchar columns. Back-patch to 9.5 where this logic appeared. David Rowley, per report from Kim Rose Carlsen Discussion: https://postgr.es/m/VI1PR05MB17091F9A9876528055D6A827C76D0@VI1PR05MB1709.eurprd05.prod.outlook.com --- src/backend/optimizer/plan/analyzejoins.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/src/backend/optimizer/plan/analyzejoins.c b/src/backend/optimizer/plan/analyzejoins.c index 34317fe7782..511603b5810 100644 --- a/src/backend/optimizer/plan/analyzejoins.c +++ b/src/backend/optimizer/plan/analyzejoins.c @@ -703,6 +703,14 @@ rel_is_distinct_for(PlannerInfo *root, RelOptInfo *rel, List *clause_list) else var = (Var *) get_leftop(rinfo->clause); + /* + * We may ignore any RelabelType node above the operand. (There + * won't be more than one, since eval_const_expressions() has been + * applied already.) + */ + if (var && IsA(var, RelabelType)) + var = (Var *) ((RelabelType *) var)->arg; + /* * If inner side isn't a Var referencing a subquery output column, * this clause doesn't help us.