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authorTom Lane <tgl@sss.pgh.pa.us>2017-09-17 15:28:51 -0400
committerTom Lane <tgl@sss.pgh.pa.us>2017-09-17 15:28:51 -0400
commit6f44fe7f121ac7c29c1ac8553e4e209f9c3bfbcb (patch)
tree5489479a43a5f1fe55927183e81e6bfb53935195 /src
parent27c6619e9c8ff80cd78c7f66443aa005734cda90 (diff)
downloadpostgresql-6f44fe7f121ac7c29c1ac8553e4e209f9c3bfbcb.tar.gz
postgresql-6f44fe7f121ac7c29c1ac8553e4e209f9c3bfbcb.zip
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
Diffstat (limited to 'src')
-rw-r--r--src/backend/optimizer/plan/analyzejoins.c8
1 files changed, 8 insertions, 0 deletions
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
@@ -704,6 +704,14 @@ rel_is_distinct_for(PlannerInfo *root, RelOptInfo *rel, List *clause_list)
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.
*/