Code review for make_partition_op_expr.

It's better to use the actual keynum here rather than 0, because
someday someone might try to make list partitioning work with
multiple partitioning columns.

Jeevan Ladhe

Discussion: http://postgr.es/m/CAOgcT0M6-mx+dSX47JGJuJP1CKr4XssBFVmKNETt0OZYWpFr+w@mail.gmail.com

src/backend/catalog/partition.c

@@ -1266,7 +1266,7 @@ make_partition_op_expr(PartitionKey key, int keynum,
 				saopexpr->opno = operoid;
 				saopexpr->opfuncid = get_opcode(operoid);
 				saopexpr->useOr = true;
-				saopexpr->inputcollid = key->partcollation[0];
+				saopexpr->inputcollid = key->partcollation[keynum];
 				saopexpr->args = list_make2(arg1, arg2);
 				saopexpr->location = -1;