Teach hash_ok_operator() that record_eq is only sometimes hashable.

tglsfdc · tglsfdc · commit 647889667566 · 2022-01-16T16:39:26.000-05:00
The need for this was foreseen long ago, but when record_eq actually became hashable (in commit 01e658f), we missed updating this spot. Per bug #17363 from Elvis Pranskevichus. Back-patch to v14 where the faulty commit came in. Discussion: https://postgr.es/m/17363-f6d42fd0d726be02@postgresql.org
diff --git a/src/backend/optimizer/plan/subselect.c b/src/backend/optimizer/plan/subselect.c
@@ -848,10 +848,10 @@ hash_ok_operator(OpExpr *expr)
 	/* quick out if not a binary operator */
 	if (list_length(expr->args) != 2)
 		return false;
-	if (opid == ARRAY_EQ_OP)
+	if (opid == ARRAY_EQ_OP ||
+		opid == RECORD_EQ_OP)
 	{
-		/* array_eq is strict, but must check input type to ensure hashable */
-		/* XXX record_eq will need same treatment when it becomes hashable */
+		/* these are strict, but must check input type to ensure hashable */
 		Node	   *leftarg = linitial(expr->args);
 
 		return op_hashjoinable(opid, exprType(leftarg));
diff --git a/src/test/regress/expected/subselect.out b/src/test/regress/expected/subselect.out
@@ -789,6 +789,29 @@ select 'foo'::text in (select 'bar'::name union all select 'bar'::name);
  f
 (1 row)
 
+--
+-- Test that we don't try to hash nested records (bug #17363)
+-- (Hashing could be supported, but for now we don't)
+--
+explain (verbose, costs off)
+select row(row(row(1))) = any (select row(row(1)));
+                QUERY PLAN                 
+-------------------------------------------
+ Result
+   Output: (SubPlan 1)
+   SubPlan 1
+     ->  Materialize
+           Output: '("(1)")'::record
+           ->  Result
+                 Output: '("(1)")'::record
+(7 rows)
+
+select row(row(row(1))) = any (select row(row(1)));
+ ?column? 
+----------
+ t
+(1 row)
+
 --
 -- Test case for premature memory release during hashing of subplan output
 --
diff --git a/src/test/regress/sql/subselect.sql b/src/test/regress/sql/subselect.sql
@@ -463,6 +463,16 @@ select 'foo'::text in (select 'bar'::name union all select 'bar'::name);
 
 select 'foo'::text in (select 'bar'::name union all select 'bar'::name);
 
+--
+-- Test that we don't try to hash nested records (bug #17363)
+-- (Hashing could be supported, but for now we don't)
+--
+
+explain (verbose, costs off)
+select row(row(row(1))) = any (select row(row(1)));
+
+select row(row(row(1))) = any (select row(row(1)));
+
 --
 -- Test case for premature memory release during hashing of subplan output
 --
