1 files changed, 43 insertions, 0 deletions
diff --git a/src/backend/executor/execUtils.c b/src/backend/executor/execUtils.c
index 740e8fb1486..df0223129c4 100644
--- a/src/backend/executor/execUtils.c
+++ b/src/backend/executor/execUtils.c
@@ -526,6 +526,49 @@ ExecGetResultSlotOps(PlanState *planstate, bool *isfixed)
 	return planstate->ps_ResultTupleSlot->tts_ops;
 }
 
+/*
+ * ExecGetCommonSlotOps - identify common result slot type, if any
+ *
+ * If all the given PlanState nodes return the same fixed tuple slot type,
+ * return the slot ops struct for that slot type.  Else, return NULL.
+ */
+const TupleTableSlotOps *
+ExecGetCommonSlotOps(PlanState **planstates, int nplans)
+{
+	const TupleTableSlotOps *result;
+	bool		isfixed;
+
+	if (nplans <= 0)
+		return NULL;
+	result = ExecGetResultSlotOps(planstates[0], &isfixed);
+	if (!isfixed)
+		return NULL;
+	for (int i = 1; i < nplans; i++)
+	{
+		const TupleTableSlotOps *thisops;
+
+		thisops = ExecGetResultSlotOps(planstates[i], &isfixed);
+		if (!isfixed)
+			return NULL;
+		if (result != thisops)
+			return NULL;
+	}
+	return result;
+}
+
+/*
+ * ExecGetCommonChildSlotOps - as above, for the PlanState's standard children
+ */
+const TupleTableSlotOps *
+ExecGetCommonChildSlotOps(PlanState *ps)
+{
+	PlanState  *planstates[2];
+
+	planstates[0] = outerPlanState(ps);
+	planstates[1] = innerPlanState(ps);
+	return ExecGetCommonSlotOps(planstates, 2);
+}
+
 
 /* ----------------
  *		ExecAssignProjectionInfo