1 files changed, 23 insertions, 9 deletions

diff --git a/src/backend/executor/nodeAppend.c b/src/backend/executor/nodeAppend.c
index ca0f54d676f..b5d56569f7f 100644
--- a/src/backend/executor/nodeAppend.c
+++ b/src/backend/executor/nodeAppend.c
@@ -110,6 +110,7 @@ ExecInitAppend(Append *node, EState *estate, int eflags)
 {
 	AppendState *appendstate = makeNode(AppendState);
 	PlanState **appendplanstates;
+	const TupleTableSlotOps *appendops;
 	Bitmapset  *validsubplans;
 	Bitmapset  *asyncplans;
 	int			nplans;
@@ -176,15 +177,6 @@ ExecInitAppend(Append *node, EState *estate, int eflags)
 		appendstate->as_prune_state = NULL;
 	}
 
-	/*
-	 * Initialize result tuple type and slot.
-	 */
-	ExecInitResultTupleSlotTL(&appendstate->ps, &TTSOpsVirtual);
-
-	/* node returns slots from each of its subnodes, therefore not fixed */
-	appendstate->ps.resultopsset = true;
-	appendstate->ps.resultopsfixed = false;
-
 	appendplanstates = (PlanState **) palloc(nplans *
 											 sizeof(PlanState *));
 
@@ -227,6 +219,28 @@ ExecInitAppend(Append *node, EState *estate, int eflags)
 	appendstate->appendplans = appendplanstates;
 	appendstate->as_nplans = nplans;
 
+	/*
+	 * Initialize Append's result tuple type and slot.  If the child plans all
+	 * produce the same fixed slot type, we can use that slot type; otherwise
+	 * make a virtual slot.  (Note that the result slot itself is used only to
+	 * return a null tuple at end of execution; real tuples are returned to
+	 * the caller in the children's own result slots.  What we are doing here
+	 * is allowing the parent plan node to optimize if the Append will return
+	 * only one kind of slot.)
+	 */
+	appendops = ExecGetCommonSlotOps(appendplanstates, j);
+	if (appendops != NULL)
+	{
+		ExecInitResultTupleSlotTL(&appendstate->ps, appendops);
+	}
+	else
+	{
+		ExecInitResultTupleSlotTL(&appendstate->ps, &TTSOpsVirtual);
+		/* show that the output slot type is not fixed */
+		appendstate->ps.resultopsset = true;
+		appendstate->ps.resultopsfixed = false;
+	}
+
 	/* Initialize async state */
 	appendstate->as_asyncplans = asyncplans;
 	appendstate->as_nasyncplans = nasyncplans;