Allow tupleslots to have a fixed tupledesc, use in executor nodes.

The reason for doing so is that it will allow expression evaluation to
optimize based on the underlying tupledesc. In particular it will
allow to JIT tuple deforming together with the expression itself.

For that expression initialization needs to be moved after the
relevant slots are initialized - mostly unproblematic, except in the
case of nodeWorktablescan.c.

After doing so there's no need for ExecAssignResultType() and
ExecAssignResultTypeFromTL() anymore, as all former callers have been
converted to create a slot with a fixed descriptor.

When creating a slot with a fixed descriptor, tts_values/isnull can be
allocated together with the main slot, reducing allocation overhead
and increasing cache density a bit.

Author: Andres Freund
Discussion: https://postgr.es/m/20171206093717.vqdxe5icqttpxs3p@alap3.anarazel.de

52 files changed, 566 insertions, 778 deletions

diff --git a/src/backend/commands/copy.c b/src/backend/commands/copy.c
index b3933df9aff..d5883c98d15 100644
--- a/src/backend/commands/copy.c
+++ b/src/backend/commands/copy.c
@@ -2444,10 +2444,9 @@ CopyFrom(CopyState cstate)
 	estate->es_range_table = cstate->range_table;
 
 	/* Set up a tuple slot too */
-	myslot = ExecInitExtraTupleSlot(estate);
-	ExecSetSlotDescriptor(myslot, tupDesc);
+	myslot = ExecInitExtraTupleSlot(estate, tupDesc);
 	/* Triggers might need a slot as well */
-	estate->es_trig_tuple_slot = ExecInitExtraTupleSlot(estate);
+	estate->es_trig_tuple_slot = ExecInitExtraTupleSlot(estate, NULL);
 
 	/* Prepare to catch AFTER triggers. */
 	AfterTriggerBeginQuery();
diff --git a/src/backend/commands/trigger.c b/src/backend/commands/trigger.c
index 160d941c005..fffc0095a79 100644
--- a/src/backend/commands/trigger.c
+++ b/src/backend/commands/trigger.c
@@ -3251,7 +3251,8 @@ TriggerEnabled(EState *estate, ResultRelInfo *relinfo,
 			if (estate->es_trig_oldtup_slot == NULL)
 			{
 				oldContext = MemoryContextSwitchTo(estate->es_query_cxt);
-				estate->es_trig_oldtup_slot = ExecInitExtraTupleSlot(estate);
+				estate->es_trig_oldtup_slot =
+					ExecInitExtraTupleSlot(estate, NULL);
 				MemoryContextSwitchTo(oldContext);
 			}
 			oldslot = estate->es_trig_oldtup_slot;
@@ -3264,7 +3265,8 @@ TriggerEnabled(EState *estate, ResultRelInfo *relinfo,
 			if (estate->es_trig_newtup_slot == NULL)
 			{
 				oldContext = MemoryContextSwitchTo(estate->es_query_cxt);
-				estate->es_trig_newtup_slot = ExecInitExtraTupleSlot(estate);
+				estate->es_trig_newtup_slot =
+					ExecInitExtraTupleSlot(estate, NULL);
 				MemoryContextSwitchTo(oldContext);
 			}
 			newslot = estate->es_trig_newtup_slot;
diff --git a/src/backend/executor/README b/src/backend/executor/README
index b3e74aa1a54..0d7cd552eb6 100644
--- a/src/backend/executor/README
+++ b/src/backend/executor/README
@@ -243,6 +243,8 @@ This is a sketch of control flow for full query processing:
 		switch to per-query context to run ExecInitNode
 		AfterTriggerBeginQuery
 		ExecInitNode --- recursively scans plan tree
+			ExecInitNode
+				recurse into subsidiary nodes
 			CreateExprContext
 				creates per-tuple context
 			ExecInitExpr
diff --git a/src/backend/executor/execExpr.c b/src/backend/executor/execExpr.c
index 463e185a9a9..db5fcafbfe4 100644
--- a/src/backend/executor/execExpr.c
+++ b/src/backend/executor/execExpr.c
@@ -2415,7 +2415,7 @@ ExecInitWholeRowVar(ExprEvalStep *scratch, Var *variable, ExprState *state)
 				scratch->d.wholerow.junkFilter =
 					ExecInitJunkFilter(subplan->plan->targetlist,
 									   ExecGetResultType(subplan)->tdhasoid,
-									   ExecInitExtraTupleSlot(parent->state));
+									   ExecInitExtraTupleSlot(parent->state, NULL));
 			}
 		}
 	}
diff --git a/src/backend/executor/execMain.c b/src/backend/executor/execMain.c
index 5d3e923cca3..91ba939bdca 100644
--- a/src/backend/executor/execMain.c
+++ b/src/backend/executor/execMain.c
@@ -1073,7 +1073,7 @@ InitPlan(QueryDesc *queryDesc, int eflags)
 
 			j = ExecInitJunkFilter(planstate->plan->targetlist,
 								   tupType->tdhasoid,
-								   ExecInitExtraTupleSlot(estate));
+								   ExecInitExtraTupleSlot(estate, NULL));
 			estate->es_junkFilter = j;
 
 			/* Want to return the cleaned tuple type */
diff --git a/src/backend/executor/execPartition.c b/src/backend/executor/execPartition.c
index 4048c3ebc61..00523ce250d 100644
--- a/src/backend/executor/execPartition.c
+++ b/src/backend/executor/execPartition.c
@@ -93,7 +93,7 @@ ExecSetupPartitionTupleRouting(ModifyTableState *mtstate,
 		 * We need an additional tuple slot for storing transient tuples that
 		 * are converted to the root table descriptor.
 		 */
-		proute->root_tuple_slot = MakeTupleTableSlot();
+		proute->root_tuple_slot = MakeTupleTableSlot(NULL);
 	}
 	else
 	{
@@ -112,7 +112,7 @@ ExecSetupPartitionTupleRouting(ModifyTableState *mtstate,
 	 * (such as ModifyTableState) and released when the node finishes
 	 * processing.
 	 */
-	proute->partition_tuple_slot = MakeTupleTableSlot();
+	proute->partition_tuple_slot = MakeTupleTableSlot(NULL);
 
 	i = 0;
 	foreach(cell, leaf_parts)
diff --git a/src/backend/executor/execScan.c b/src/backend/executor/execScan.c
index bf4f603fd36..caf91730ce1 100644
--- a/src/backend/executor/execScan.c
+++ b/src/backend/executor/execScan.c
@@ -229,7 +229,7 @@ ExecScan(ScanState *node,
  * the scan node, because the planner will preferentially generate a matching
  * tlist.
  *
- * ExecAssignScanType must have been called already.
+ * The scan slot's descriptor must have been set already.
  */
 void
 ExecAssignScanProjectionInfo(ScanState *node)
diff --git a/src/backend/executor/execTuples.c b/src/backend/executor/execTuples.c
index 5df89e419c8..c46d65cf938 100644
--- a/src/backend/executor/execTuples.c
+++ b/src/backend/executor/execTuples.c
@@ -58,7 +58,7 @@
  *		At ExecutorStart()
  *		----------------
  *		- ExecInitSeqScan() calls ExecInitScanTupleSlot() and
- *		  ExecInitResultTupleSlot() to construct TupleTableSlots
+ *		  ExecInitResultTupleSlotTL() to construct TupleTableSlots
  *		  for the tuples returned by the access methods and the
  *		  tuples resulting from performing target list projections.
  *
@@ -104,19 +104,36 @@ static TupleDesc ExecTypeFromTLInternal(List *targetList,
 /* --------------------------------
  *		MakeTupleTableSlot
  *
- *		Basic routine to make an empty TupleTableSlot.
+ *		Basic routine to make an empty TupleTableSlot. If tupleDesc is
+ *		specified the slot's descriptor is fixed for it's lifetime, gaining
+ *		some efficiency. If that's undesirable, pass NULL.
  * --------------------------------
  */
 TupleTableSlot *
-MakeTupleTableSlot(void)
+MakeTupleTableSlot(TupleDesc tupleDesc)
 {
-	TupleTableSlot *slot = makeNode(TupleTableSlot);
+	Size		sz;
+	TupleTableSlot *slot;
 
+	/*
+	 * When a fixed descriptor is specified, we can reduce overhead by
+	 * allocating the entire slot in one go.
+	 */
+	if (tupleDesc)
+		sz = MAXALIGN(sizeof(TupleTableSlot)) +
+			MAXALIGN(tupleDesc->natts * sizeof(Datum)) +
+			MAXALIGN(tupleDesc->natts * sizeof(bool));
+	else
+		sz = sizeof(TupleTableSlot);
+
+	slot = palloc0(sz);
+	slot->type = T_TupleTableSlot;
 	slot->tts_isempty = true;
 	slot->tts_shouldFree = false;
 	slot->tts_shouldFreeMin = false;
 	slot->tts_tuple = NULL;
-	slot->tts_tupleDescriptor = NULL;
+	slot->tts_fixedTupleDescriptor = tupleDesc != NULL;
+	slot->tts_tupleDescriptor = tupleDesc;
 	slot->tts_mcxt = CurrentMemoryContext;
 	slot->tts_buffer = InvalidBuffer;
 	slot->tts_nvalid = 0;
@@ -124,6 +141,19 @@ MakeTupleTableSlot(void)
 	slot->tts_isnull = NULL;
 	slot->tts_mintuple = NULL;
 
+	if (tupleDesc != NULL)
+	{
+		slot->tts_values = (Datum *)
+			(((char *) slot)
+			 + MAXALIGN(sizeof(TupleTableSlot)));
+		slot->tts_isnull = (bool *)
+			(((char *) slot)
+			 + MAXALIGN(sizeof(TupleTableSlot))
+			 + MAXALIGN(tupleDesc->natts * sizeof(Datum)));
+
+		PinTupleDesc(tupleDesc);
+	}
+
 	return slot;
 }
 
@@ -134,9 +164,9 @@ MakeTupleTableSlot(void)
  * --------------------------------
  */
 TupleTableSlot *
-ExecAllocTableSlot(List **tupleTable)
+ExecAllocTableSlot(List **tupleTable, TupleDesc desc)
 {
-	TupleTableSlot *slot = MakeTupleTableSlot();
+	TupleTableSlot *slot = MakeTupleTableSlot(desc);
 
 	*tupleTable = lappend(*tupleTable, slot);
 
@@ -173,10 +203,13 @@ ExecResetTupleTable(List *tupleTable,	/* tuple table */
 		/* If shouldFree, release memory occupied by the slot itself */
 		if (shouldFree)
 		{
-			if (slot->tts_values)
-				pfree(slot->tts_values);
-			if (slot->tts_isnull)
-				pfree(slot->tts_isnull);
+			if (!slot->tts_fixedTupleDescriptor)
+			{
+				if (slot->tts_values)
+					pfree(slot->tts_values);
+				if (slot->tts_isnull)
+					pfree(slot->tts_isnull);
+			}
 			pfree(slot);
 		}
 	}
@@ -198,9 +231,7 @@ ExecResetTupleTable(List *tupleTable,	/* tuple table */
 TupleTableSlot *
 MakeSingleTupleTableSlot(TupleDesc tupdesc)
 {
-	TupleTableSlot *slot = MakeTupleTableSlot();
-
-	ExecSetSlotDescriptor(slot, tupdesc);
+	TupleTableSlot *slot = MakeTupleTableSlot(tupdesc);
 
 	return slot;
 }
@@ -220,10 +251,13 @@ ExecDropSingleTupleTableSlot(TupleTableSlot *slot)
 	ExecClearTuple(slot);
 	if (slot->tts_tupleDescriptor)
 		ReleaseTupleDesc(slot->tts_tupleDescriptor);
-	if (slot->tts_values)
-		pfree(slot->tts_values);
-	if (slot->tts_isnull)
-		pfree(slot->tts_isnull);
+	if (!slot->tts_fixedTupleDescriptor)
+	{
+		if (slot->tts_values)
+			pfree(slot->tts_values);
+		if (slot->tts_isnull)
+			pfree(slot->tts_isnull);
+	}
 	pfree(slot);
 }
 
@@ -247,6 +281,8 @@ void
 ExecSetSlotDescriptor(TupleTableSlot *slot, /* slot to change */
 					  TupleDesc tupdesc)	/* new tuple descriptor */
 {
+	Assert(!slot->tts_fixedTupleDescriptor);
+
 	/* For safety, make sure slot is empty before changing it */
 	ExecClearTuple(slot);
 
@@ -816,7 +852,7 @@ ExecCopySlot(TupleTableSlot *dstslot, TupleTableSlot *srcslot)
  */
 
 /* --------------------------------
- *		ExecInit{Result,Scan,Extra}TupleSlot
+ *		ExecInit{Result,Scan,Extra}TupleSlot[TL]
  *
  *		These are convenience routines to initialize the specified slot
  *		in nodes inheriting the appropriate state.  ExecInitExtraTupleSlot
@@ -825,13 +861,30 @@ ExecCopySlot(TupleTableSlot *dstslot, TupleTableSlot *srcslot)
  */
 
 /* ----------------
- *		ExecInitResultTupleSlot
+ *		ExecInitResultTupleSlotTL
+ *
+ *		Initialize result tuple slot, using the plan node's targetlist.
  * ----------------
  */
 void
-ExecInitResultTupleSlot(EState *estate, PlanState *planstate)
+ExecInitResultTupleSlotTL(EState *estate, PlanState *planstate)
 {
-	planstate->ps_ResultTupleSlot = ExecAllocTableSlot(&estate->es_tupleTable);
+	bool		hasoid;
+	TupleDesc	tupDesc;
+
+	if (ExecContextForcesOids(planstate, &hasoid))
+	{
+		/* context forces OID choice; hasoid is now set correctly */
+	}
+	else
+	{
+		/* given free choice, don't leave space for OIDs in result tuples */
+		hasoid = false;
+	}
+
+	tupDesc = ExecTypeFromTL(planstate->plan->targetlist, hasoid);
+
+	planstate->ps_ResultTupleSlot = ExecAllocTableSlot(&estate->es_tupleTable, tupDesc);
 }
 
 /* ----------------
@@ -839,19 +892,24 @@ ExecInitResultTupleSlot(EState *estate, PlanState *planstate)
  * ----------------
  */
 void
-ExecInitScanTupleSlot(EState *estate, ScanState *scanstate)
+ExecInitScanTupleSlot(EState *estate, ScanState *scanstate, TupleDesc tupledesc)
 {
-	scanstate->ss_ScanTupleSlot = ExecAllocTableSlot(&estate->es_tupleTable);
+	scanstate->ss_ScanTupleSlot = ExecAllocTableSlot(&estate->es_tupleTable,
+													 tupledesc);
 }
 
 /* ----------------
  *		ExecInitExtraTupleSlot
+ *
+ * Return a newly created slot. If tupledesc is non-NULL the slot will have
+ * that as its fixed tupledesc. Otherwise the caller needs to use
+ * ExecSetSlotDescriptor() to set the descriptor before use.
  * ----------------
  */
 TupleTableSlot *
-ExecInitExtraTupleSlot(EState *estate)
+ExecInitExtraTupleSlot(EState *estate, TupleDesc tupledesc)
 {
-	return ExecAllocTableSlot(&estate->es_tupleTable);
+	return ExecAllocTableSlot(&estate->es_tupleTable, tupledesc);
 }
 
 /* ----------------
@@ -865,9 +923,7 @@ ExecInitExtraTupleSlot(EState *estate)
 TupleTableSlot *
 ExecInitNullTupleSlot(EState *estate, TupleDesc tupType)
 {
-	TupleTableSlot *slot = ExecInitExtraTupleSlot(estate);
-
-	ExecSetSlotDescriptor(slot, tupType);
+	TupleTableSlot *slot = ExecInitExtraTupleSlot(estate, tupType);
 
 	return ExecStoreAllNullTuple(slot);
 }
diff --git a/src/backend/executor/execUtils.c b/src/backend/executor/execUtils.c
index 50b6edce63d..a8ae37ebc80 100644
--- a/src/backend/executor/execUtils.c
+++ b/src/backend/executor/execUtils.c
@@ -22,7 +22,6 @@
  *		ReScanExprContext
  *
  *		ExecAssignExprContext	Common code for plan node init routines.
- *		ExecAssignResultType
  *		etc
  *
  *		ExecOpenScanRelation	Common code for scan node init routines.
@@ -429,47 +428,6 @@ ExecAssignExprContext(EState *estate, PlanState *planstate)
 }
 
 /* ----------------
- *		ExecAssignResultType
- * ----------------
- */
-void
-ExecAssignResultType(PlanState *planstate, TupleDesc tupDesc)
-{
-	TupleTableSlot *slot = planstate->ps_ResultTupleSlot;
-
-	ExecSetSlotDescriptor(slot, tupDesc);
-}
-
-/* ----------------
- *		ExecAssignResultTypeFromTL
- * ----------------
- */
-void
-ExecAssignResultTypeFromTL(PlanState *planstate)
-{
-	bool		hasoid;
-	TupleDesc	tupDesc;
-
-	if (ExecContextForcesOids(planstate, &hasoid))
-	{
-		/* context forces OID choice; hasoid is now set correctly */
-	}
-	else
-	{
-		/* given free choice, don't leave space for OIDs in result tuples */
-		hasoid = false;
-	}
-
-	/*
-	 * ExecTypeFromTL needs the parse-time representation of the tlist, not a
-	 * list of ExprStates.  This is good because some plan nodes don't bother
-	 * to set up planstate->targetlist ...
-	 */
-	tupDesc = ExecTypeFromTL(planstate->plan->targetlist, hasoid);
-	ExecAssignResultType(planstate, tupDesc);
-}
-
-/* ----------------
  *		ExecGetResultType
  * ----------------
  */
@@ -609,13 +567,9 @@ ExecFreeExprContext(PlanState *planstate)
 	planstate->ps_ExprContext = NULL;
 }
 
+
 /* ----------------------------------------------------------------
- *		the following scan type support functions are for
- *		those nodes which are stubborn and return tuples in
- *		their Scan tuple slot instead of their Result tuple
- *		slot..  luck fur us, these nodes do not do projections
- *		so we don't have to worry about getting the ProjectionInfo
- *		right for them...  -cim 6/3/91
+ *				  Scan node support
  * ----------------------------------------------------------------
  */
 
@@ -632,11 +586,11 @@ ExecAssignScanType(ScanState *scanstate, TupleDesc tupDesc)
 }
 
 /* ----------------
- *		ExecAssignScanTypeFromOuterPlan
+ *		ExecCreateSlotFromOuterPlan
  * ----------------
  */
 void
-ExecAssignScanTypeFromOuterPlan(ScanState *scanstate)
+ExecCreateScanSlotFromOuterPlan(EState *estate, ScanState *scanstate)
 {
 	PlanState  *outerPlan;
 	TupleDesc	tupDesc;
@@ -644,15 +598,9 @@ ExecAssignScanTypeFromOuterPlan(ScanState *scanstate)
 	outerPlan = outerPlanState(scanstate);
 	tupDesc = ExecGetResultType(outerPlan);
 
-	ExecAssignScanType(scanstate, tupDesc);
+	ExecInitScanTupleSlot(estate, scanstate, tupDesc);
 }
 
-
-/* ----------------------------------------------------------------
- *				  Scan node support
- * ----------------------------------------------------------------
- */
-
 /* ----------------------------------------------------------------
  *		ExecRelationIsTargetRelation
  *
diff --git a/src/backend/executor/nodeAgg.c b/src/backend/executor/nodeAgg.c
index e74b3a93911..1b1334006fa 100644
--- a/src/backend/executor/nodeAgg.c
+++ b/src/backend/executor/nodeAgg.c
@@ -1402,8 +1402,8 @@ find_hash_columns(AggState *aggstate)
 							  perhash->aggnode->grpOperators,
 							  &perhash->eqfuncoids,
 							  &perhash->hashfunctions);
-		perhash->hashslot = ExecAllocTableSlot(&estate->es_tupleTable);
-		ExecSetSlotDescriptor(perhash->hashslot, hashDesc);
+		perhash->hashslot =
+			ExecAllocTableSlot(&estate->es_tupleTable, hashDesc);
 
 		list_free(hashTlist);
 		bms_free(colnos);
@@ -2199,31 +2199,6 @@ ExecInitAgg(Agg *node, EState *estate, int eflags)
 	ExecAssignExprContext(estate, &aggstate->ss.ps);
 
 	/*
-	 * tuple table initialization.
-	 *
-	 * For hashtables, we create some additional slots below.
-	 */
-	ExecInitScanTupleSlot(estate, &aggstate->ss);
-	ExecInitResultTupleSlot(estate, &aggstate->ss.ps);
-	aggstate->sort_slot = ExecInitExtraTupleSlot(estate);
-
-	/*
-	 * initialize child expressions
-	 *
-	 * We expect the parser to have checked that no aggs contain other agg
-	 * calls in their arguments (and just to be sure, we verify it again while
-	 * initializing the plan node).  This would make no sense under SQL
-	 * semantics, and it's forbidden by the spec.  Because it is true, we
-	 * don't need to worry about evaluating the aggs in any particular order.
-	 *
-	 * Note: execExpr.c finds Aggrefs for us, and adds their AggrefExprState
-	 * nodes to aggstate->aggs.  Aggrefs in the qual are found here; Aggrefs
-	 * in the targetlist are found during ExecAssignProjectionInfo, below.
-	 */
-	aggstate->ss.ps.qual =
-		ExecInitQual(node->plan.qual, (PlanState *) aggstate);
-
-	/*
 	 * Initialize child nodes.
 	 *
 	 * If we are doing a hashed aggregation then the child plan does not need
@@ -2237,18 +2212,34 @@ ExecInitAgg(Agg *node, EState *estate, int eflags)
 	/*
 	 * initialize source tuple type.
 	 */
-	ExecAssignScanTypeFromOuterPlan(&aggstate->ss);
+	ExecCreateScanSlotFromOuterPlan(estate, &aggstate->ss);
 	scanDesc = aggstate->ss.ss_ScanTupleSlot->tts_tupleDescriptor;
 	if (node->chain)
-		ExecSetSlotDescriptor(aggstate->sort_slot, scanDesc);
+		aggstate->sort_slot = ExecInitExtraTupleSlot(estate, scanDesc);
 
 	/*
-	 * Initialize result tuple type and projection info.
+	 * Initialize result type, slot and projection.
 	 */
-	ExecAssignResultTypeFromTL(&aggstate->ss.ps);
+	ExecInitResultTupleSlotTL(estate, &aggstate->ss.ps);
 	ExecAssignProjectionInfo(&aggstate->ss.ps, NULL);
 
 	/*
+	 * initialize child expressions
+	 *
+	 * We expect the parser to have checked that no aggs contain other agg
+	 * calls in their arguments (and just to be sure, we verify it again while
+	 * initializing the plan node).  This would make no sense under SQL
+	 * semantics, and it's forbidden by the spec.  Because it is true, we
+	 * don't need to worry about evaluating the aggs in any particular order.
+	 *
+	 * Note: execExpr.c finds Aggrefs for us, and adds their AggrefExprState
+	 * nodes to aggstate->aggs.  Aggrefs in the qual are found here; Aggrefs
+	 * in the targetlist are found during ExecAssignProjectionInfo, below.
+	 */
+	aggstate->ss.ps.qual =
+		ExecInitQual(node->plan.qual, (PlanState *) aggstate);
+
+	/*
 	 * We should now have found all Aggrefs in the targetlist and quals.
 	 */
 	numaggs = aggstate->numaggs;
@@ -3071,8 +3062,8 @@ build_pertrans_for_aggref(AggStatePerTrans pertrans,
 	if (numSortCols > 0 || aggref->aggfilter)
 	{
 		pertrans->sortdesc = ExecTypeFromTL(aggref->args, false);
-		pertrans->sortslot = ExecInitExtraTupleSlot(estate);
-		ExecSetSlotDescriptor(pertrans->sortslot, pertrans->sortdesc);
+		pertrans->sortslot =
+			ExecInitExtraTupleSlot(estate, pertrans->sortdesc);
 	}
 
 	if (numSortCols > 0)
@@ -3093,9 +3084,8 @@ build_pertrans_for_aggref(AggStatePerTrans pertrans,
 		else if (numDistinctCols > 0)
 		{
 			/* we will need an extra slot to store prior values */
-			pertrans->uniqslot = ExecInitExtraTupleSlot(estate);
-			ExecSetSlotDescriptor(pertrans->uniqslot,
-								  pertrans->sortdesc);
+			pertrans->uniqslot =
+				ExecInitExtraTupleSlot(estate, pertrans->sortdesc);
 		}
 
 		/* Extract the sort information for use later */
diff --git a/src/backend/executor/nodeAppend.c b/src/backend/executor/nodeAppend.c
index 264d8fea8d9..7a3dd2ee2d0 100644
--- a/src/backend/executor/nodeAppend.c
+++ b/src/backend/executor/nodeAppend.c
@@ -129,17 +129,9 @@ ExecInitAppend(Append *node, EState *estate, int eflags)
 	appendstate->as_nplans = nplans;
 
 	/*
-	 * Miscellaneous initialization
-	 *
-	 * Append plans don't have expression contexts because they never call
-	 * ExecQual or ExecProject.
+	 * Initialize result tuple type and slot.
 	 */
-
-	/*
-	 * append nodes still have Result slots, which hold pointers to tuples, so
-	 * we have to initialize them.
-	 */
-	ExecInitResultTupleSlot(estate, &appendstate->ps);
+	ExecInitResultTupleSlotTL(estate, &appendstate->ps);
 
 	/*
 	 * call ExecInitNode on each of the plans to be executed and save the
@@ -155,9 +147,11 @@ ExecInitAppend(Append *node, EState *estate, int eflags)
 	}
 
 	/*
-	 * initialize output tuple type
+	 * Miscellaneous initialization
+	 *
+	 * Append plans don't have expression contexts because they never call
+	 * ExecQual or ExecProject.
 	 */
-	ExecAssignResultTypeFromTL(&appendstate->ps);
 	appendstate->ps.ps_ProjInfo = NULL;
 
 	/*
diff --git a/src/backend/executor/nodeBitmapAnd.c b/src/backend/executor/nodeBitmapAnd.c
index 913046c987e..23d0d943269 100644
--- a/src/backend/executor/nodeBitmapAnd.c
+++ b/src/backend/executor/nodeBitmapAnd.c
@@ -81,13 +81,6 @@ ExecInitBitmapAnd(BitmapAnd *node, EState *estate, int eflags)
 	bitmapandstate->nplans = nplans;
 
 	/*
-	 * Miscellaneous initialization
-	 *
-	 * BitmapAnd plans don't have expression contexts because they never call
-	 * ExecQual or ExecProject.  They don't need any tuple slots either.
-	 */
-
-	/*
 	 * call ExecInitNode on each of the plans to be executed and save the
 	 * results into the array "bitmapplanstates".
 	 */
@@ -99,6 +92,13 @@ ExecInitBitmapAnd(BitmapAnd *node, EState *estate, int eflags)
 		i++;
 	}
 
+	/*
+	 * Miscellaneous initialization
+	 *
+	 * BitmapAnd plans don't have expression contexts because they never call
+	 * ExecQual or ExecProject.  They don't need any tuple slots either.
+	 */
+
 	return bitmapandstate;
 }
 
diff --git a/src/backend/executor/nodeBitmapHeapscan.c b/src/backend/executor/nodeBitmapHeapscan.c
index fa65d4efbe7..3e1c9e07145 100644
--- a/src/backend/executor/nodeBitmapHeapscan.c
+++ b/src/backend/executor/nodeBitmapHeapscan.c
@@ -907,23 +907,39 @@ ExecInitBitmapHeapScan(BitmapHeapScan *node, EState *estate, int eflags)
 	ExecAssignExprContext(estate, &scanstate->ss.ps);
 
 	/*
-	 * initialize child expressions
+	 * open the base relation and acquire appropriate lock on it.
 	 */
-	scanstate->ss.ps.qual =
-		ExecInitQual(node->scan.plan.qual, (PlanState *) scanstate);
-	scanstate->bitmapqualorig =
-		ExecInitQual(node->bitmapqualorig, (PlanState *) scanstate);
+	currentRelation = ExecOpenScanRelation(estate, node->scan.scanrelid, eflags);
+
+	/*
+	 * initialize child nodes
+	 *
+	 * We do this after ExecOpenScanRelation because the child nodes will open
+	 * indexscans on our relation's indexes, and we want to be sure we have
+	 * acquired a lock on the relation first.
+	 */
+	outerPlanState(scanstate) = ExecInitNode(outerPlan(node), estate, eflags);
 
 	/*
-	 * tuple table initialization
+	 * get the scan type from the relation descriptor.
 	 */
-	ExecInitResultTupleSlot(estate, &scanstate->ss.ps);
-	ExecInitScanTupleSlot(estate, &scanstate->ss);
+	ExecInitScanTupleSlot(estate, &scanstate->ss,
+						  RelationGetDescr(currentRelation));
+
 
 	/*
-	 * open the base relation and acquire appropriate lock on it.
+	 * Initialize result slot, type and projection.
 	 */
-	currentRelation = ExecOpenScanRelation(estate, node->scan.scanrelid, eflags);
+	ExecInitResultTupleSlotTL(estate, &scanstate->ss.ps);
+	ExecAssignScanProjectionInfo(&scanstate->ss);
+
+	/*
+	 * initialize child expressions
+	 */
+	scanstate->ss.ps.qual =
+		ExecInitQual(node->scan.plan.qual, (PlanState *) scanstate);
+	scanstate->bitmapqualorig =
+		ExecInitQual(node->bitmapqualorig, (PlanState *) scanstate);
 
 	/*
 	 * Determine the maximum for prefetch_target.  If the tablespace has a
@@ -953,26 +969,6 @@ ExecInitBitmapHeapScan(BitmapHeapScan *node, EState *estate, int eflags)
 														 NULL);
 
 	/*
-	 * get the scan type from the relation descriptor.
-	 */
-	ExecAssignScanType(&scanstate->ss, RelationGetDescr(currentRelation));
-
-	/*
-	 * Initialize result tuple type and projection info.
-	 */
-	ExecAssignResultTypeFromTL(&scanstate->ss.ps);
-	ExecAssignScanProjectionInfo(&scanstate->ss);
-
-	/*
-	 * initialize child nodes
-	 *
-	 * We do this last because the child nodes will open indexscans on our
-	 * relation's indexes, and we want to be sure we have acquired a lock on
-	 * the relation first.
-	 */
-	outerPlanState(scanstate) = ExecInitNode(outerPlan(node), estate, eflags);
-
-	/*
 	 * all done.
 	 */
 	return scanstate;
diff --git a/src/backend/executor/nodeBitmapIndexscan.c b/src/backend/executor/nodeBitmapIndexscan.c
index bb5e4da187c..d04f4901b48 100644
--- a/src/backend/executor/nodeBitmapIndexscan.c
+++ b/src/backend/executor/nodeBitmapIndexscan.c
@@ -227,6 +227,15 @@ ExecInitBitmapIndexScan(BitmapIndexScan *node, EState *estate, int eflags)
 	indexstate->biss_result = NULL;
 
 	/*
+	 * We do not open or lock the base relation here.  We assume that an
+	 * ancestor BitmapHeapScan node is holding AccessShareLock (or better) on
+	 * the heap relation throughout the execution of the plan tree.
+	 */
+
+	indexstate->ss.ss_currentRelation = NULL;
+	indexstate->ss.ss_currentScanDesc = NULL;
+
+	/*
 	 * Miscellaneous initialization
 	 *
 	 * We do not need a standard exprcontext for this node, though we may
@@ -243,15 +252,6 @@ ExecInitBitmapIndexScan(BitmapIndexScan *node, EState *estate, int eflags)
 	 */
 
 	/*
-	 * We do not open or lock the base relation here.  We assume that an
-	 * ancestor BitmapHeapScan node is holding AccessShareLock (or better) on
-	 * the heap relation throughout the execution of the plan tree.
-	 */
-
-	indexstate->ss.ss_currentRelation = NULL;
-	indexstate->ss.ss_currentScanDesc = NULL;
-
-	/*
 	 * If we are just doing EXPLAIN (ie, aren't going to run the plan), stop
 	 * here.  This allows an index-advisor plugin to EXPLAIN a plan containing
 	 * references to nonexistent indexes.
diff --git a/src/backend/executor/nodeBitmapOr.c b/src/backend/executor/nodeBitmapOr.c
index 8047549f7df..3f0a0a05442 100644
--- a/src/backend/executor/nodeBitmapOr.c
+++ b/src/backend/executor/nodeBitmapOr.c
@@ -82,13 +82,6 @@ ExecInitBitmapOr(BitmapOr *node, EState *estate, int eflags)
 	bitmaporstate->nplans = nplans;
 
 	/*
-	 * Miscellaneous initialization
-	 *
-	 * BitmapOr plans don't have expression contexts because they never call
-	 * ExecQual or ExecProject.  They don't need any tuple slots either.
-	 */
-
-	/*
 	 * call ExecInitNode on each of the plans to be executed and save the
 	 * results into the array "bitmapplanstates".
 	 */
@@ -100,6 +93,13 @@ ExecInitBitmapOr(BitmapOr *node, EState *estate, int eflags)
 		i++;
 	}
 
+	/*
+	 * Miscellaneous initialization
+	 *
+	 * BitmapOr plans don't have expression contexts because they never call
+	 * ExecQual or ExecProject.  They don't need any tuple slots either.
+	 */
+
 	return bitmaporstate;
 }
 
diff --git a/src/backend/executor/nodeCtescan.c b/src/backend/executor/nodeCtescan.c
index ec6d75cbd41..218619c760d 100644
--- a/src/backend/executor/nodeCtescan.c
+++ b/src/backend/executor/nodeCtescan.c
@@ -243,30 +243,24 @@ ExecInitCteScan(CteScan *node, EState *estate, int eflags)
 	ExecAssignExprContext(estate, &scanstate->ss.ps);
 
 	/*
-	 * initialize child expressions
-	 */
-	scanstate->ss.ps.qual =
-		ExecInitQual(node->scan.plan.qual, (PlanState *) scanstate);
-
-	/*
-	 * tuple table initialization
-	 */
-	ExecInitResultTupleSlot(estate, &scanstate->ss.ps);
-	ExecInitScanTupleSlot(estate, &scanstate->ss);
-
-	/*
 	 * The scan tuple type (ie, the rowtype we expect to find in the work
 	 * table) is the same as the result rowtype of the CTE query.
 	 */
-	ExecAssignScanType(&scanstate->ss,
-					   ExecGetResultType(scanstate->cteplanstate));
+	ExecInitScanTupleSlot(estate, &scanstate->ss,
+						  ExecGetResultType(scanstate->cteplanstate));
 
 	/*
-	 * Initialize result tuple type and projection info.
+	 * Initialize result slot, type and projection.
 	 */
-	ExecAssignResultTypeFromTL(&scanstate->ss.ps);
+	ExecInitResultTupleSlotTL(estate, &scanstate->ss.ps);
 	ExecAssignScanProjectionInfo(&scanstate->ss);
 
+	/*
+	 * initialize child expressions
+	 */
+	scanstate->ss.ps.qual =
+		ExecInitQual(node->scan.plan.qual, (PlanState *) scanstate);
+
 	return scanstate;
 }
 
diff --git a/src/backend/executor/nodeCustom.c b/src/backend/executor/nodeCustom.c
index 936a2221f51..b816e0b31db 100644
--- a/src/backend/executor/nodeCustom.c
+++ b/src/backend/executor/nodeCustom.c
@@ -54,14 +54,6 @@ ExecInitCustomScan(CustomScan *cscan, EState *estate, int eflags)
 	/* create expression context for node */
 	ExecAssignExprContext(estate, &css->ss.ps);
 
-	/* initialize child expressions */
-	css->ss.ps.qual =
-		ExecInitQual(cscan->scan.plan.qual, (PlanState *) css);
-
-	/* tuple table initialization */
-	ExecInitScanTupleSlot(estate, &css->ss);
-	ExecInitResultTupleSlot(estate, &css->ss.ps);
-
 	/*
 	 * open the base relation, if any, and acquire an appropriate lock on it
 	 */
@@ -81,23 +73,27 @@ ExecInitCustomScan(CustomScan *cscan, EState *estate, int eflags)
 		TupleDesc	scan_tupdesc;
 
 		scan_tupdesc = ExecTypeFromTL(cscan->custom_scan_tlist, false);
-		ExecAssignScanType(&css->ss, scan_tupdesc);
+		ExecInitScanTupleSlot(estate, &css->ss, scan_tupdesc);
 		/* Node's targetlist will contain Vars with varno = INDEX_VAR */
 		tlistvarno = INDEX_VAR;
 	}
 	else
 	{
-		ExecAssignScanType(&css->ss, RelationGetDescr(scan_rel));
+		ExecInitScanTupleSlot(estate, &css->ss, RelationGetDescr(scan_rel));
 		/* Node's targetlist will contain Vars with varno = scanrelid */
 		tlistvarno = scanrelid;
 	}
 
 	/*
-	 * Initialize result tuple type and projection info.
+	 * Initialize result slot, type and projection.
 	 */
-	ExecAssignResultTypeFromTL(&css->ss.ps);
+	ExecInitResultTupleSlotTL(estate, &css->ss.ps);
 	ExecAssignScanProjectionInfoWithVarno(&css->ss, tlistvarno);
 
+	/* initialize child expressions */
+	css->ss.ps.qual =
+		ExecInitQual(cscan->scan.plan.qual, (PlanState *) css);
+
 	/*
 	 * The callback of custom-scan provider applies the final initialization
 	 * of the custom-scan-state node according to its logic.
diff --git a/src/backend/executor/nodeForeignscan.c b/src/backend/executor/nodeForeignscan.c
index 59865f5ccad..0084234b350 100644
--- a/src/backend/executor/nodeForeignscan.c
+++ b/src/backend/executor/nodeForeignscan.c
@@ -156,20 +156,6 @@ ExecInitForeignScan(ForeignScan *node, EState *estate, int eflags)
 	ExecAssignExprContext(estate, &scanstate->ss.ps);
 
 	/*
-	 * initialize child expressions
-	 */
-	scanstate->ss.ps.qual =
-		ExecInitQual(node->scan.plan.qual, (PlanState *) scanstate);
-	scanstate->fdw_recheck_quals =
-		ExecInitQual(node->fdw_recheck_quals, (PlanState *) scanstate);
-
-	/*
-	 * tuple table initialization
-	 */
-	ExecInitResultTupleSlot(estate, &scanstate->ss.ps);
-	ExecInitScanTupleSlot(estate, &scanstate->ss);
-
-	/*
 	 * open the base relation, if any, and acquire an appropriate lock on it;
 	 * also acquire function pointers from the FDW's handler
 	 */
@@ -194,24 +180,32 @@ ExecInitForeignScan(ForeignScan *node, EState *estate, int eflags)
 		TupleDesc	scan_tupdesc;
 
 		scan_tupdesc = ExecTypeFromTL(node->fdw_scan_tlist, false);
-		ExecAssignScanType(&scanstate->ss, scan_tupdesc);
+		ExecInitScanTupleSlot(estate, &scanstate->ss, scan_tupdesc);
 		/* Node's targetlist will contain Vars with varno = INDEX_VAR */
 		tlistvarno = INDEX_VAR;
 	}
 	else
 	{
-		ExecAssignScanType(&scanstate->ss, RelationGetDescr(currentRelation));
+		ExecInitScanTupleSlot(estate, &scanstate->ss, RelationGetDescr(currentRelation));
 		/* Node's targetlist will contain Vars with varno = scanrelid */
 		tlistvarno = scanrelid;
 	}
 
 	/*
-	 * Initialize result tuple type and projection info.
+	 * Initialize result slot, type and projection.
 	 */
-	ExecAssignResultTypeFromTL(&scanstate->ss.ps);
+	ExecInitResultTupleSlotTL(estate, &scanstate->ss.ps);
 	ExecAssignScanProjectionInfoWithVarno(&scanstate->ss, tlistvarno);
 
 	/*
+	 * initialize child expressions
+	 */
+	scanstate->ss.ps.qual =
+		ExecInitQual(node->scan.plan.qual, (PlanState *) scanstate);
+	scanstate->fdw_recheck_quals =
+		ExecInitQual(node->fdw_recheck_quals, (PlanState *) scanstate);
+
+	/*
 	 * Initialize FDW-related state.
 	 */
 	scanstate->fdwroutine = fdwroutine;
diff --git a/src/backend/executor/nodeFunctionscan.c b/src/backend/executor/nodeFunctionscan.c
index 69f8d3e8145..fb7c9f67875 100644
--- a/src/backend/executor/nodeFunctionscan.c
+++ b/src/backend/executor/nodeFunctionscan.c
@@ -334,18 +334,6 @@ ExecInitFunctionScan(FunctionScan *node, EState *estate, int eflags)
 	 */
 	ExecAssignExprContext(estate, &scanstate->ss.ps);
 
-	/*
-	 * tuple table initialization
-	 */
-	ExecInitResultTupleSlot(estate, &scanstate->ss.ps);
-	ExecInitScanTupleSlot(estate, &scanstate->ss);
-
-	/*
-	 * initialize child expressions
-	 */
-	scanstate->ss.ps.qual =
-		ExecInitQual(node->scan.plan.qual, (PlanState *) scanstate);
-
 	scanstate->funcstates = palloc(nfuncs * sizeof(FunctionScanPerFuncState));
 
 	natts = 0;
@@ -436,8 +424,7 @@ ExecInitFunctionScan(FunctionScan *node, EState *estate, int eflags)
 		 */
 		if (!scanstate->simple)
 		{
-			fs->func_slot = ExecInitExtraTupleSlot(estate);
-			ExecSetSlotDescriptor(fs->func_slot, fs->tupdesc);
+			fs->func_slot = ExecInitExtraTupleSlot(estate, fs->tupdesc);
 		}
 		else
 			fs->func_slot = NULL;
@@ -492,15 +479,24 @@ ExecInitFunctionScan(FunctionScan *node, EState *estate, int eflags)
 		Assert(attno == natts);
 	}
 
-	ExecAssignScanType(&scanstate->ss, scan_tupdesc);
+	/*
+	 * Initialize scan slot and type.
+	 */
+	ExecInitScanTupleSlot(estate, &scanstate->ss, scan_tupdesc);
 
 	/*
-	 * Initialize result tuple type and projection info.
+	 * Initialize result slot, type and projection.
 	 */
-	ExecAssignResultTypeFromTL(&scanstate->ss.ps);
+	ExecInitResultTupleSlotTL(estate, &scanstate->ss.ps);
 	ExecAssignScanProjectionInfo(&scanstate->ss);
 
 	/*
+	 * initialize child expressions
+	 */
+	scanstate->ss.ps.qual =
+		ExecInitQual(node->scan.plan.qual, (PlanState *) scanstate);
+
+	/*
 	 * Create a memory context that ExecMakeTableFunctionResult can use to
 	 * evaluate function arguments in.  We can't use the per-tuple context for
 	 * this because it gets reset too often; but we don't want to leak
diff --git a/src/backend/executor/nodeGather.c b/src/backend/executor/nodeGather.c
index 58eadd45b83..eaf7d2d5632 100644
--- a/src/backend/executor/nodeGather.c
+++ b/src/backend/executor/nodeGather.c
@@ -59,7 +59,6 @@ ExecInitGather(Gather *node, EState *estate, int eflags)
 {
 	GatherState *gatherstate;
 	Plan	   *outerNode;
-	bool		hasoid;
 	TupleDesc	tupDesc;
 
 	/* Gather node doesn't have innerPlan node. */
@@ -86,36 +85,28 @@ ExecInitGather(Gather *node, EState *estate, int eflags)
 	ExecAssignExprContext(estate, &gatherstate->ps);
 
 	/*
-	 * Gather doesn't support checking a qual (it's always more efficient to
-	 * do it in the child node).
-	 */
-	Assert(!node->plan.qual);
-
-	/*
-	 * tuple table initialization
-	 */
-	gatherstate->funnel_slot = ExecInitExtraTupleSlot(estate);
-	ExecInitResultTupleSlot(estate, &gatherstate->ps);
-
-	/*
 	 * now initialize outer plan
 	 */
 	outerNode = outerPlan(node);
 	outerPlanState(gatherstate) = ExecInitNode(outerNode, estate, eflags);
+	tupDesc = ExecGetResultType(outerPlanState(gatherstate));
+
+	/*
+	 * Initialize result slot, type and projection.
+	 */
+	ExecInitResultTupleSlotTL(estate, &gatherstate->ps);
+	ExecConditionalAssignProjectionInfo(&gatherstate->ps, tupDesc, OUTER_VAR);
 
 	/*
 	 * Initialize funnel slot to same tuple descriptor as outer plan.
 	 */
-	if (!ExecContextForcesOids(outerPlanState(gatherstate), &hasoid))
-		hasoid = false;
-	tupDesc = ExecTypeFromTL(outerNode->targetlist, hasoid);
-	ExecSetSlotDescriptor(gatherstate->funnel_slot, tupDesc);
+	gatherstate->funnel_slot = ExecInitExtraTupleSlot(estate, tupDesc);
 
 	/*
-	 * Initialize result tuple type and projection info.
+	 * Gather doesn't support checking a qual (it's always more efficient to
+	 * do it in the child node).
 	 */
-	ExecAssignResultTypeFromTL(&gatherstate->ps);
-	ExecConditionalAssignProjectionInfo(&gatherstate->ps, tupDesc, OUTER_VAR);
+	Assert(!node->plan.qual);
 
 	return gatherstate;
 }
diff --git a/src/backend/executor/nodeGatherMerge.c b/src/backend/executor/nodeGatherMerge.c
index 6858c91e8c2..83221cdbaee 100644
--- a/src/backend/executor/nodeGatherMerge.c
+++ b/src/backend/executor/nodeGatherMerge.c
@@ -73,7 +73,6 @@ ExecInitGatherMerge(GatherMerge *node, EState *estate, int eflags)
 {
 	GatherMergeState *gm_state;
 	Plan	   *outerNode;
-	bool		hasoid;
 	TupleDesc	tupDesc;
 
 	/* Gather merge node doesn't have innerPlan node. */
@@ -105,11 +104,6 @@ ExecInitGatherMerge(GatherMerge *node, EState *estate, int eflags)
 	Assert(!node->plan.qual);
 
 	/*
-	 * tuple table initialization
-	 */
-	ExecInitResultTupleSlot(estate, &gm_state->ps);
-
-	/*
 	 * now initialize outer plan
 	 */
 	outerNode = outerPlan(node);
@@ -119,15 +113,13 @@ ExecInitGatherMerge(GatherMerge *node, EState *estate, int eflags)
 	 * Store the tuple descriptor into gather merge state, so we can use it
 	 * while initializing the gather merge slots.
 	 */
-	if (!ExecContextForcesOids(outerPlanState(gm_state), &hasoid))
-		hasoid = false;
-	tupDesc = ExecTypeFromTL(outerNode->targetlist, hasoid);
+	tupDesc = ExecGetResultType(outerPlanState(gm_state));
 	gm_state->tupDesc = tupDesc;
 
 	/*
-	 * Initialize result tuple type and projection info.
+	 * Initialize result slot, type and projection.
 	 */
-	ExecAssignResultTypeFromTL(&gm_state->ps);
+	ExecInitResultTupleSlotTL(estate, &gm_state->ps);
 	ExecConditionalAssignProjectionInfo(&gm_state->ps, tupDesc, OUTER_VAR);
 
 	/*
@@ -410,9 +402,8 @@ gather_merge_setup(GatherMergeState *gm_state)
 			(HeapTuple *) palloc0(sizeof(HeapTuple) * MAX_TUPLE_STORE);
 
 		/* Initialize tuple slot for worker */
-		gm_state->gm_slots[i + 1] = ExecInitExtraTupleSlot(gm_state->ps.state);
-		ExecSetSlotDescriptor(gm_state->gm_slots[i + 1],
-							  gm_state->tupDesc);
+		gm_state->gm_slots[i + 1] =
+			ExecInitExtraTupleSlot(gm_state->ps.state, gm_state->tupDesc);
 	}
 
 	/* Allocate the resources for the merge */
diff --git a/src/backend/executor/nodeGroup.c b/src/backend/executor/nodeGroup.c
index 8f7bf459efe..c6efd64d00d 100644
--- a/src/backend/executor/nodeGroup.c
+++ b/src/backend/executor/nodeGroup.c
@@ -182,34 +182,28 @@ ExecInitGroup(Group *node, EState *estate, int eflags)
 	ExecAssignExprContext(estate, &grpstate->ss.ps);
 
 	/*
-	 * tuple table initialization
-	 */
-	ExecInitScanTupleSlot(estate, &grpstate->ss);
-	ExecInitResultTupleSlot(estate, &grpstate->ss.ps);
-
-	/*
-	 * initialize child expressions
-	 */
-	grpstate->ss.ps.qual =
-		ExecInitQual(node->plan.qual, (PlanState *) grpstate);
-
-	/*
 	 * initialize child nodes
 	 */
 	outerPlanState(grpstate) = ExecInitNode(outerPlan(node), estate, eflags);
 
 	/*
-	 * initialize tuple type.
+	 * Initialize scan slot and type.
 	 */
-	ExecAssignScanTypeFromOuterPlan(&grpstate->ss);
+	ExecCreateScanSlotFromOuterPlan(estate, &grpstate->ss);
 
 	/*
-	 * Initialize result tuple type and projection info.
+	 * Initialize result slot, type and projection.
 	 */
-	ExecAssignResultTypeFromTL(&grpstate->ss.ps);
+	ExecInitResultTupleSlotTL(estate, &grpstate->ss.ps);
 	ExecAssignProjectionInfo(&grpstate->ss.ps, NULL);
 
 	/*
+	 * initialize child expressions
+	 */
+	grpstate->ss.ps.qual =
+		ExecInitQual(node->plan.qual, (PlanState *) grpstate);
+
+	/*
 	 * Precompute fmgr lookup data for inner loop
 	 */
 	grpstate->eqfunction =
diff --git a/src/backend/executor/nodeHash.c b/src/backend/executor/nodeHash.c
index b10f8474527..06bb44b1631 100644
--- a/src/backend/executor/nodeHash.c
+++ b/src/backend/executor/nodeHash.c
@@ -374,28 +374,23 @@ ExecInitHash(Hash *node, EState *estate, int eflags)
 	ExecAssignExprContext(estate, &hashstate->ps);
 
 	/*
-	 * initialize our result slot
-	 */
-	ExecInitResultTupleSlot(estate, &hashstate->ps);
-
-	/*
-	 * initialize child expressions
-	 */
-	hashstate->ps.qual =
-		ExecInitQual(node->plan.qual, (PlanState *) hashstate);
-
-	/*
 	 * initialize child nodes
 	 */
 	outerPlanState(hashstate) = ExecInitNode(outerPlan(node), estate, eflags);
 
 	/*
-	 * initialize tuple type. no need to initialize projection info because
-	 * this node doesn't do projections
+	 * initialize our result slot and type. No need to build projection
+	 * because this node doesn't do projections.
 	 */
-	ExecAssignResultTypeFromTL(&hashstate->ps);
+	ExecInitResultTupleSlotTL(estate, &hashstate->ps);
 	hashstate->ps.ps_ProjInfo = NULL;
 
+	/*
+	 * initialize child expressions
+	 */
+	hashstate->ps.qual =
+		ExecInitQual(node->plan.qual, (PlanState *) hashstate);
+
 	return hashstate;
 }
 
diff --git a/src/backend/executor/nodeHashjoin.c b/src/backend/executor/nodeHashjoin.c
index 03d78042fa0..ab91eb25273 100644
--- a/src/backend/executor/nodeHashjoin.c
+++ b/src/backend/executor/nodeHashjoin.c
@@ -596,6 +596,7 @@ ExecInitHashJoin(HashJoin *node, EState *estate, int eflags)
 	List	   *lclauses;
 	List	   *rclauses;
 	List	   *hoperators;
+	TupleDesc	outerDesc, innerDesc;
 	ListCell   *l;
 
 	/* check for unsupported flags */
@@ -614,6 +615,7 @@ ExecInitHashJoin(HashJoin *node, EState *estate, int eflags)
 	 * managed to launch a parallel query.
 	 */
 	hjstate->js.ps.ExecProcNode = ExecHashJoin;
+	hjstate->js.jointype = node->join.jointype;
 
 	/*
 	 * Miscellaneous initialization
@@ -623,17 +625,6 @@ ExecInitHashJoin(HashJoin *node, EState *estate, int eflags)
 	ExecAssignExprContext(estate, &hjstate->js.ps);
 
 	/*
-	 * initialize child expressions
-	 */
-	hjstate->js.ps.qual =
-		ExecInitQual(node->join.plan.qual, (PlanState *) hjstate);
-	hjstate->js.jointype = node->join.jointype;
-	hjstate->js.joinqual =
-		ExecInitQual(node->join.joinqual, (PlanState *) hjstate);
-	hjstate->hashclauses =
-		ExecInitQual(node->hashclauses, (PlanState *) hjstate);
-
-	/*
 	 * initialize child nodes
 	 *
 	 * Note: we could suppress the REWIND flag for the inner input, which
@@ -644,13 +635,20 @@ ExecInitHashJoin(HashJoin *node, EState *estate, int eflags)
 	hashNode = (Hash *) innerPlan(node);
 
 	outerPlanState(hjstate) = ExecInitNode(outerNode, estate, eflags);
+	outerDesc = ExecGetResultType(outerPlanState(hjstate));
 	innerPlanState(hjstate) = ExecInitNode((Plan *) hashNode, estate, eflags);
+	innerDesc = ExecGetResultType(innerPlanState(hjstate));
+
+	/*
+	 * Initialize result slot, type and projection.
+	 */
+	ExecInitResultTupleSlotTL(estate, &hjstate->js.ps);
+	ExecAssignProjectionInfo(&hjstate->js.ps, NULL);
 
 	/*
 	 * tuple table initialization
 	 */
-	ExecInitResultTupleSlot(estate, &hjstate->js.ps);
-	hjstate->hj_OuterTupleSlot = ExecInitExtraTupleSlot(estate);
+	hjstate->hj_OuterTupleSlot = ExecInitExtraTupleSlot(estate, outerDesc);
 
 	/*
 	 * detect whether we need only consider the first matching inner tuple
@@ -667,21 +665,17 @@ ExecInitHashJoin(HashJoin *node, EState *estate, int eflags)
 		case JOIN_LEFT:
 		case JOIN_ANTI:
 			hjstate->hj_NullInnerTupleSlot =
-				ExecInitNullTupleSlot(estate,
-									  ExecGetResultType(innerPlanState(hjstate)));
+				ExecInitNullTupleSlot(estate, innerDesc);
 			break;
 		case JOIN_RIGHT:
 			hjstate->hj_NullOuterTupleSlot =
-				ExecInitNullTupleSlot(estate,
-									  ExecGetResultType(outerPlanState(hjstate)));
+				ExecInitNullTupleSlot(estate, outerDesc);
 			break;
 		case JOIN_FULL:
 			hjstate->hj_NullOuterTupleSlot =
-				ExecInitNullTupleSlot(estate,
-									  ExecGetResultType(outerPlanState(hjstate)));
+				ExecInitNullTupleSlot(estate, outerDesc);
 			hjstate->hj_NullInnerTupleSlot =
-				ExecInitNullTupleSlot(estate,
-									  ExecGetResultType(innerPlanState(hjstate)));
+				ExecInitNullTupleSlot(estate, innerDesc);
 			break;
 		default:
 			elog(ERROR, "unrecognized join type: %d",
@@ -703,13 +697,14 @@ ExecInitHashJoin(HashJoin *node, EState *estate, int eflags)
 	}
 
 	/*
-	 * initialize tuple type and projection info
+	 * initialize child expressions
 	 */
-	ExecAssignResultTypeFromTL(&hjstate->js.ps);
-	ExecAssignProjectionInfo(&hjstate->js.ps, NULL);
-
-	ExecSetSlotDescriptor(hjstate->hj_OuterTupleSlot,
-						  ExecGetResultType(outerPlanState(hjstate)));
+	hjstate->js.ps.qual =
+		ExecInitQual(node->join.plan.qual, (PlanState *) hjstate);
+	hjstate->js.joinqual =
+		ExecInitQual(node->join.joinqual, (PlanState *) hjstate);
+	hjstate->hashclauses =
+		ExecInitQual(node->hashclauses, (PlanState *) hjstate);
 
 	/*
 	 * initialize hash-specific info
diff --git a/src/backend/executor/nodeIndexonlyscan.c b/src/backend/executor/nodeIndexonlyscan.c
index 8ffcc52bea5..ddc0ae90615 100644
--- a/src/backend/executor/nodeIndexonlyscan.c
+++ b/src/backend/executor/nodeIndexonlyscan.c
@@ -519,23 +519,6 @@ ExecInitIndexOnlyScan(IndexOnlyScan *node, EState *estate, int eflags)
 	ExecAssignExprContext(estate, &indexstate->ss.ps);
 
 	/*
-	 * initialize child expressions
-	 *
-	 * Note: we don't initialize all of the indexorderby expression, only the
-	 * sub-parts corresponding to runtime keys (see below).
-	 */
-	indexstate->ss.ps.qual =
-		ExecInitQual(node->scan.plan.qual, (PlanState *) indexstate);
-	indexstate->indexqual =
-		ExecInitQual(node->indexqual, (PlanState *) indexstate);
-
-	/*
-	 * tuple table initialization
-	 */
-	ExecInitResultTupleSlot(estate, &indexstate->ss.ps);
-	ExecInitScanTupleSlot(estate, &indexstate->ss);
-
-	/*
 	 * open the base relation and acquire appropriate lock on it.
 	 */
 	currentRelation = ExecOpenScanRelation(estate, node->scan.scanrelid, eflags);
@@ -551,17 +534,28 @@ ExecInitIndexOnlyScan(IndexOnlyScan *node, EState *estate, int eflags)
 	 * suitable data anyway.)
 	 */
 	tupDesc = ExecTypeFromTL(node->indextlist, false);
-	ExecAssignScanType(&indexstate->ss, tupDesc);
+	ExecInitScanTupleSlot(estate, &indexstate->ss, tupDesc);
 
 	/*
-	 * Initialize result tuple type and projection info.  The node's
+	 * Initialize result slot, type and projection info.  The node's
 	 * targetlist will contain Vars with varno = INDEX_VAR, referencing the
 	 * scan tuple.
 	 */
-	ExecAssignResultTypeFromTL(&indexstate->ss.ps);
+	ExecInitResultTupleSlotTL(estate, &indexstate->ss.ps);
 	ExecAssignScanProjectionInfoWithVarno(&indexstate->ss, INDEX_VAR);
 
 	/*
+	 * initialize child expressions
+	 *
+	 * Note: we don't initialize all of the indexorderby expression, only the
+	 * sub-parts corresponding to runtime keys (see below).
+	 */
+	indexstate->ss.ps.qual =
+		ExecInitQual(node->scan.plan.qual, (PlanState *) indexstate);
+	indexstate->indexqual =
+		ExecInitQual(node->indexqual, (PlanState *) indexstate);
+
+	/*
 	 * If we are just doing EXPLAIN (ie, aren't going to run the plan), stop
 	 * here.  This allows an index-advisor plugin to EXPLAIN a plan containing
 	 * references to nonexistent indexes.
diff --git a/src/backend/executor/nodeIndexscan.c b/src/backend/executor/nodeIndexscan.c
index b8b961add4c..01c9de88f4d 100644
--- a/src/backend/executor/nodeIndexscan.c
+++ b/src/backend/executor/nodeIndexscan.c
@@ -941,6 +941,26 @@ ExecInitIndexScan(IndexScan *node, EState *estate, int eflags)
 	ExecAssignExprContext(estate, &indexstate->ss.ps);
 
 	/*
+	 * open the base relation and acquire appropriate lock on it.
+	 */
+	currentRelation = ExecOpenScanRelation(estate, node->scan.scanrelid, eflags);
+
+	indexstate->ss.ss_currentRelation = currentRelation;
+	indexstate->ss.ss_currentScanDesc = NULL;	/* no heap scan here */
+
+	/*
+	 * get the scan type from the relation descriptor.
+	 */
+	ExecInitScanTupleSlot(estate, &indexstate->ss,
+						  RelationGetDescr(currentRelation));
+
+	/*
+	 * Initialize result slot, type and projection.
+	 */
+	ExecInitResultTupleSlotTL(estate, &indexstate->ss.ps);
+	ExecAssignScanProjectionInfo(&indexstate->ss);
+
+	/*
 	 * initialize child expressions
 	 *
 	 * Note: we don't initialize all of the indexqual expression, only the
@@ -958,31 +978,6 @@ ExecInitIndexScan(IndexScan *node, EState *estate, int eflags)
 		ExecInitExprList(node->indexorderbyorig, (PlanState *) indexstate);
 
 	/*
-	 * tuple table initialization
-	 */
-	ExecInitResultTupleSlot(estate, &indexstate->ss.ps);
-	ExecInitScanTupleSlot(estate, &indexstate->ss);
-
-	/*
-	 * open the base relation and acquire appropriate lock on it.
-	 */
-	currentRelation = ExecOpenScanRelation(estate, node->scan.scanrelid, eflags);
-
-	indexstate->ss.ss_currentRelation = currentRelation;
-	indexstate->ss.ss_currentScanDesc = NULL;	/* no heap scan here */
-
-	/*
-	 * get the scan type from the relation descriptor.
-	 */
-	ExecAssignScanType(&indexstate->ss, RelationGetDescr(currentRelation));
-
-	/*
-	 * Initialize result tuple type and projection info.
-	 */
-	ExecAssignResultTypeFromTL(&indexstate->ss.ps);
-	ExecAssignScanProjectionInfo(&indexstate->ss);
-
-	/*
 	 * If we are just doing EXPLAIN (ie, aren't going to run the plan), stop
 	 * here.  This allows an index-advisor plugin to EXPLAIN a plan containing
 	 * references to nonexistent indexes.
diff --git a/src/backend/executor/nodeLimit.c b/src/backend/executor/nodeLimit.c
index 29d2deac23b..56d98b4490b 100644
--- a/src/backend/executor/nodeLimit.c
+++ b/src/backend/executor/nodeLimit.c
@@ -354,6 +354,12 @@ ExecInitLimit(Limit *node, EState *estate, int eflags)
 	ExecAssignExprContext(estate, &limitstate->ps);
 
 	/*
+	 * initialize outer plan
+	 */
+	outerPlan = outerPlan(node);
+	outerPlanState(limitstate) = ExecInitNode(outerPlan, estate, eflags);
+
+	/*
 	 * initialize child expressions
 	 */
 	limitstate->limitOffset = ExecInitExpr((Expr *) node->limitOffset,
@@ -362,21 +368,15 @@ ExecInitLimit(Limit *node, EState *estate, int eflags)
 										  (PlanState *) limitstate);
 
 	/*
-	 * Tuple table initialization (XXX not actually used...)
+	 * Initialize result slot and type. (XXX not actually used, but upper
+	 * nodes access it to get this node's result tupledesc...)
 	 */
-	ExecInitResultTupleSlot(estate, &limitstate->ps);
-
-	/*
-	 * then initialize outer plan
-	 */
-	outerPlan = outerPlan(node);
-	outerPlanState(limitstate) = ExecInitNode(outerPlan, estate, eflags);
+	ExecInitResultTupleSlotTL(estate, &limitstate->ps);
 
 	/*
 	 * limit nodes do no projections, so initialize projection info for this
 	 * node appropriately
 	 */
-	ExecAssignResultTypeFromTL(&limitstate->ps);
 	limitstate->ps.ps_ProjInfo = NULL;
 
 	return limitstate;
diff --git a/src/backend/executor/nodeLockRows.c b/src/backend/executor/nodeLockRows.c
index 7961b4be6ab..b39ccf7dc13 100644
--- a/src/backend/executor/nodeLockRows.c
+++ b/src/backend/executor/nodeLockRows.c
@@ -370,13 +370,15 @@ ExecInitLockRows(LockRows *node, EState *estate, int eflags)
 	/*
 	 * Miscellaneous initialization
 	 *
-	 * LockRows nodes never call ExecQual or ExecProject.
+	 * LockRows nodes never call ExecQual or ExecProject, therefore no
+	 * ExprContext is needed.
 	 */
 
 	/*
-	 * Tuple table initialization (XXX not actually used...)
+	 * Tuple table initialization (XXX not actually used, but upper nodes
+	 * access it to get this node's result tupledesc...)
 	 */
-	ExecInitResultTupleSlot(estate, &lrstate->ps);
+	ExecInitResultTupleSlotTL(estate, &lrstate->ps);
 
 	/*
 	 * then initialize outer plan
@@ -387,7 +389,6 @@ ExecInitLockRows(LockRows *node, EState *estate, int eflags)
 	 * LockRows nodes do no projections, so initialize projection info for
 	 * this node appropriately
 	 */
-	ExecAssignResultTypeFromTL(&lrstate->ps);
 	lrstate->ps.ps_ProjInfo = NULL;
 
 	/*
diff --git a/src/backend/executor/nodeMaterial.c b/src/backend/executor/nodeMaterial.c
index 85afe87c443..8c2e57dbd07 100644
--- a/src/backend/executor/nodeMaterial.c
+++ b/src/backend/executor/nodeMaterial.c
@@ -207,14 +207,6 @@ ExecInitMaterial(Material *node, EState *estate, int eflags)
 	 */
 
 	/*
-	 * tuple table initialization
-	 *
-	 * material nodes only return tuples from their materialized relation.
-	 */
-	ExecInitResultTupleSlot(estate, &matstate->ss.ps);
-	ExecInitScanTupleSlot(estate, &matstate->ss);
-
-	/*
 	 * initialize child nodes
 	 *
 	 * We shield the child node from the need to support REWIND, BACKWARD, or
@@ -226,13 +218,19 @@ ExecInitMaterial(Material *node, EState *estate, int eflags)
 	outerPlanState(matstate) = ExecInitNode(outerPlan, estate, eflags);
 
 	/*
-	 * initialize tuple type.  no need to initialize projection info because
-	 * this node doesn't do projections.
+	 * Initialize result type and slot. No need to initialize projection info
+	 * because this node doesn't do projections.
+	 *
+	 * material nodes only return tuples from their materialized relation.
 	 */
-	ExecAssignResultTypeFromTL(&matstate->ss.ps);
-	ExecAssignScanTypeFromOuterPlan(&matstate->ss);
+	ExecInitResultTupleSlotTL(estate, &matstate->ss.ps);
 	matstate->ss.ps.ps_ProjInfo = NULL;
 
+	/*
+	 * initialize tuple type.
+	 */
+	ExecCreateScanSlotFromOuterPlan(estate, &matstate->ss);
+
 	return matstate;
 }
 
diff --git a/src/backend/executor/nodeMergeAppend.c b/src/backend/executor/nodeMergeAppend.c
index ab4009c967e..118f4ef07df 100644
--- a/src/backend/executor/nodeMergeAppend.c
+++ b/src/backend/executor/nodeMergeAppend.c
@@ -109,7 +109,7 @@ ExecInitMergeAppend(MergeAppend *node, EState *estate, int eflags)
 	 * MergeAppend nodes do have Result slots, which hold pointers to tuples,
 	 * so we have to initialize them.
 	 */
-	ExecInitResultTupleSlot(estate, &mergestate->ps);
+	ExecInitResultTupleSlotTL(estate, &mergestate->ps);
 
 	/*
 	 * call ExecInitNode on each of the plans to be executed and save the
@@ -124,10 +124,6 @@ ExecInitMergeAppend(MergeAppend *node, EState *estate, int eflags)
 		i++;
 	}
 
-	/*
-	 * initialize output tuple type
-	 */
-	ExecAssignResultTypeFromTL(&mergestate->ps);
 	mergestate->ps.ps_ProjInfo = NULL;
 
 	/*
diff --git a/src/backend/executor/nodeMergejoin.c b/src/backend/executor/nodeMergejoin.c
index ec5f82f6a92..f3cbe2f889b 100644
--- a/src/backend/executor/nodeMergejoin.c
+++ b/src/backend/executor/nodeMergejoin.c
@@ -1436,6 +1436,7 @@ MergeJoinState *
 ExecInitMergeJoin(MergeJoin *node, EState *estate, int eflags)
 {
 	MergeJoinState *mergestate;
+	TupleDesc	outerDesc, innerDesc;
 
 	/* check for unsupported flags */
 	Assert(!(eflags & (EXEC_FLAG_BACKWARD | EXEC_FLAG_MARK)));
@@ -1450,6 +1451,8 @@ ExecInitMergeJoin(MergeJoin *node, EState *estate, int eflags)
 	mergestate->js.ps.plan = (Plan *) node;
 	mergestate->js.ps.state = estate;
 	mergestate->js.ps.ExecProcNode = ExecMergeJoin;
+	mergestate->js.jointype = node->join.jointype;
+	mergestate->mj_ConstFalseJoin = false;
 
 	/*
 	 * Miscellaneous initialization
@@ -1467,17 +1470,6 @@ ExecInitMergeJoin(MergeJoin *node, EState *estate, int eflags)
 	mergestate->mj_InnerEContext = CreateExprContext(estate);
 
 	/*
-	 * initialize child expressions
-	 */
-	mergestate->js.ps.qual =
-		ExecInitQual(node->join.plan.qual, (PlanState *) mergestate);
-	mergestate->js.jointype = node->join.jointype;
-	mergestate->js.joinqual =
-		ExecInitQual(node->join.joinqual, (PlanState *) mergestate);
-	mergestate->mj_ConstFalseJoin = false;
-	/* mergeclauses are handled below */
-
-	/*
 	 * initialize child nodes
 	 *
 	 * inner child must support MARK/RESTORE, unless we have detected that we
@@ -1488,10 +1480,12 @@ ExecInitMergeJoin(MergeJoin *node, EState *estate, int eflags)
 	mergestate->mj_SkipMarkRestore = node->skip_mark_restore;
 
 	outerPlanState(mergestate) = ExecInitNode(outerPlan(node), estate, eflags);
+	outerDesc = ExecGetResultType(outerPlanState(mergestate));
 	innerPlanState(mergestate) = ExecInitNode(innerPlan(node), estate,
 											  mergestate->mj_SkipMarkRestore ?
 											  eflags :
 											  (eflags | EXEC_FLAG_MARK));
+	innerDesc = ExecGetResultType(innerPlanState(mergestate));
 
 	/*
 	 * For certain types of inner child nodes, it is advantageous to issue
@@ -1515,13 +1509,24 @@ ExecInitMergeJoin(MergeJoin *node, EState *estate, int eflags)
 		mergestate->mj_ExtraMarks = false;
 
 	/*
+	 * Initialize result slot, type and projection.
+	 */
+	ExecInitResultTupleSlotTL(estate, &mergestate->js.ps);
+	ExecAssignProjectionInfo(&mergestate->js.ps, NULL);
+
+	/*
 	 * tuple table initialization
 	 */
-	ExecInitResultTupleSlot(estate, &mergestate->js.ps);
+	mergestate->mj_MarkedTupleSlot = ExecInitExtraTupleSlot(estate, innerDesc);
 
-	mergestate->mj_MarkedTupleSlot = ExecInitExtraTupleSlot(estate);
-	ExecSetSlotDescriptor(mergestate->mj_MarkedTupleSlot,
-						  ExecGetResultType(innerPlanState(mergestate)));
+	/*
+	 * initialize child expressions
+	 */
+	mergestate->js.ps.qual =
+		ExecInitQual(node->join.plan.qual, (PlanState *) mergestate);
+	mergestate->js.joinqual =
+		ExecInitQual(node->join.joinqual, (PlanState *) mergestate);
+	/* mergeclauses are handled below */
 
 	/*
 	 * detect whether we need only consider the first matching inner tuple
@@ -1542,15 +1547,13 @@ ExecInitMergeJoin(MergeJoin *node, EState *estate, int eflags)
 			mergestate->mj_FillOuter = true;
 			mergestate->mj_FillInner = false;
 			mergestate->mj_NullInnerTupleSlot =
-				ExecInitNullTupleSlot(estate,
-									  ExecGetResultType(innerPlanState(mergestate)));
+				ExecInitNullTupleSlot(estate, innerDesc);
 			break;
 		case JOIN_RIGHT:
 			mergestate->mj_FillOuter = false;
 			mergestate->mj_FillInner = true;
 			mergestate->mj_NullOuterTupleSlot =
-				ExecInitNullTupleSlot(estate,
-									  ExecGetResultType(outerPlanState(mergestate)));
+				ExecInitNullTupleSlot(estate, outerDesc);
 
 			/*
 			 * Can't handle right or full join with non-constant extra
@@ -1566,11 +1569,9 @@ ExecInitMergeJoin(MergeJoin *node, EState *estate, int eflags)
 			mergestate->mj_FillOuter = true;
 			mergestate->mj_FillInner = true;
 			mergestate->mj_NullOuterTupleSlot =
-				ExecInitNullTupleSlot(estate,
-									  ExecGetResultType(outerPlanState(mergestate)));
+				ExecInitNullTupleSlot(estate, outerDesc);
 			mergestate->mj_NullInnerTupleSlot =
-				ExecInitNullTupleSlot(estate,
-									  ExecGetResultType(innerPlanState(mergestate)));
+				ExecInitNullTupleSlot(estate, innerDesc);
 
 			/*
 			 * Can't handle right or full join with non-constant extra
@@ -1588,12 +1589,6 @@ ExecInitMergeJoin(MergeJoin *node, EState *estate, int eflags)
 	}
 
 	/*
-	 * initialize tuple type and projection info
-	 */
-	ExecAssignResultTypeFromTL(&mergestate->js.ps);
-	ExecAssignProjectionInfo(&mergestate->js.ps, NULL);
-
-	/*
 	 * preprocess the merge clauses
 	 */
 	mergestate->mj_NumClauses = list_length(node->mergeclauses);
diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c
index 2a8ecbd830d..93c03cfb071 100644
--- a/src/backend/executor/nodeModifyTable.c
+++ b/src/backend/executor/nodeModifyTable.c
@@ -2367,8 +2367,7 @@ ExecInitModifyTable(ModifyTable *node, EState *estate, int eflags)
 		mtstate->ps.plan->targetlist = (List *) linitial(node->returningLists);
 
 		/* Set up a slot for the output of the RETURNING projection(s) */
-		ExecInitResultTupleSlot(estate, &mtstate->ps);
-		ExecAssignResultTypeFromTL(&mtstate->ps);
+		ExecInitResultTupleSlotTL(estate, &mtstate->ps);
 		slot = mtstate->ps.ps_ResultTupleSlot;
 
 		/* Need an econtext too */
@@ -2435,8 +2434,7 @@ ExecInitModifyTable(ModifyTable *node, EState *estate, int eflags)
 		 * expects one (maybe should change that?).
 		 */
 		mtstate->ps.plan->targetlist = NIL;
-		ExecInitResultTupleSlot(estate, &mtstate->ps);
-		ExecAssignResultTypeFromTL(&mtstate->ps);
+		ExecInitResultTupleSlotTL(estate, &mtstate->ps);
 
 		mtstate->ps.ps_ExprContext = NULL;
 	}
@@ -2449,6 +2447,7 @@ ExecInitModifyTable(ModifyTable *node, EState *estate, int eflags)
 	if (node->onConflictAction == ONCONFLICT_UPDATE)
 	{
 		ExprContext *econtext;
+		TupleDesc	relationDesc;
 		TupleDesc	tupDesc;
 
 		/* insert may only have one plan, inheritance is not expanded */
@@ -2459,26 +2458,26 @@ ExecInitModifyTable(ModifyTable *node, EState *estate, int eflags)
 			ExecAssignExprContext(estate, &mtstate->ps);
 
 		econtext = mtstate->ps.ps_ExprContext;
+		relationDesc = resultRelInfo->ri_RelationDesc->rd_att;
 
 		/* initialize slot for the existing tuple */
-		mtstate->mt_existing = ExecInitExtraTupleSlot(mtstate->ps.state);
-		ExecSetSlotDescriptor(mtstate->mt_existing,
-							  resultRelInfo->ri_RelationDesc->rd_att);
+		mtstate->mt_existing =
+			ExecInitExtraTupleSlot(mtstate->ps.state, relationDesc);
 
 		/* carried forward solely for the benefit of explain */
 		mtstate->mt_excludedtlist = node->exclRelTlist;
 
 		/* create target slot for UPDATE SET projection */
 		tupDesc = ExecTypeFromTL((List *) node->onConflictSet,
-								 resultRelInfo->ri_RelationDesc->rd_rel->relhasoids);
-		mtstate->mt_conflproj = ExecInitExtraTupleSlot(mtstate->ps.state);
-		ExecSetSlotDescriptor(mtstate->mt_conflproj, tupDesc);
+								 relationDesc->tdhasoid);
+		mtstate->mt_conflproj =
+			ExecInitExtraTupleSlot(mtstate->ps.state, tupDesc);
 
 		/* build UPDATE SET projection state */
 		resultRelInfo->ri_onConflictSetProj =
 			ExecBuildProjectionInfo(node->onConflictSet, econtext,
 									mtstate->mt_conflproj, &mtstate->ps,
-									resultRelInfo->ri_RelationDesc->rd_att);
+									relationDesc);
 
 		/* build DO UPDATE WHERE clause expression */
 		if (node->onConflictWhere)
@@ -2583,7 +2582,7 @@ ExecInitModifyTable(ModifyTable *node, EState *estate, int eflags)
 
 				j = ExecInitJunkFilter(subplan->targetlist,
 									   resultRelInfo->ri_RelationDesc->rd_att->tdhasoid,
-									   ExecInitExtraTupleSlot(estate));
+									   ExecInitExtraTupleSlot(estate, NULL));
 
 				if (operation == CMD_UPDATE || operation == CMD_DELETE)
 				{
@@ -2633,7 +2632,7 @@ ExecInitModifyTable(ModifyTable *node, EState *estate, int eflags)
 	 * we keep it in the estate.
 	 */
 	if (estate->es_trig_tuple_slot == NULL)
-		estate->es_trig_tuple_slot = ExecInitExtraTupleSlot(estate);
+		estate->es_trig_tuple_slot = ExecInitExtraTupleSlot(estate, NULL);
 
 	/*
 	 * Lastly, if this is not the primary (canSetTag) ModifyTable node, add it
diff --git a/src/backend/executor/nodeNamedtuplestorescan.c b/src/backend/executor/nodeNamedtuplestorescan.c
index c3b28176e44..4d898b1f83e 100644
--- a/src/backend/executor/nodeNamedtuplestorescan.c
+++ b/src/backend/executor/nodeNamedtuplestorescan.c
@@ -133,26 +133,21 @@ ExecInitNamedTuplestoreScan(NamedTuplestoreScan *node, EState *estate, int eflag
 	ExecAssignExprContext(estate, &scanstate->ss.ps);
 
 	/*
-	 * initialize child expressions
+	 * Tuple table and result type initialization. The scan tuple type is
+	 * specified for the tuplestore.
 	 */
-	scanstate->ss.ps.qual =
-		ExecInitQual(node->scan.plan.qual, (PlanState *) scanstate);
+	ExecInitResultTupleSlotTL(estate, &scanstate->ss.ps);
+	ExecInitScanTupleSlot(estate, &scanstate->ss, scanstate->tupdesc);
 
 	/*
-	 * tuple table initialization
-	 */
-	ExecInitResultTupleSlot(estate, &scanstate->ss.ps);
-	ExecInitScanTupleSlot(estate, &scanstate->ss);
-
-	/*
-	 * The scan tuple type is specified for the tuplestore.
+	 * initialize child expressions
 	 */
-	ExecAssignScanType(&scanstate->ss, scanstate->tupdesc);
+	scanstate->ss.ps.qual =
+		ExecInitQual(node->scan.plan.qual, (PlanState *) scanstate);
 
 	/*
-	 * Initialize result tuple type and projection info.
+	 * Initialize projection.
 	 */
-	ExecAssignResultTypeFromTL(&scanstate->ss.ps);
 	ExecAssignScanProjectionInfo(&scanstate->ss);
 
 	return scanstate;
diff --git a/src/backend/executor/nodeNestloop.c b/src/backend/executor/nodeNestloop.c
index 9b4f8cc4320..9ae9863226c 100644
--- a/src/backend/executor/nodeNestloop.c
+++ b/src/backend/executor/nodeNestloop.c
@@ -286,15 +286,6 @@ ExecInitNestLoop(NestLoop *node, EState *estate, int eflags)
 	ExecAssignExprContext(estate, &nlstate->js.ps);
 
 	/*
-	 * initialize child expressions
-	 */
-	nlstate->js.ps.qual =
-		ExecInitQual(node->join.plan.qual, (PlanState *) nlstate);
-	nlstate->js.jointype = node->join.jointype;
-	nlstate->js.joinqual =
-		ExecInitQual(node->join.joinqual, (PlanState *) nlstate);
-
-	/*
 	 * initialize child nodes
 	 *
 	 * If we have no parameters to pass into the inner rel from the outer,
@@ -311,9 +302,19 @@ ExecInitNestLoop(NestLoop *node, EState *estate, int eflags)
 	innerPlanState(nlstate) = ExecInitNode(innerPlan(node), estate, eflags);
 
 	/*
-	 * tuple table initialization
+	 * Initialize result slot, type and projection.
 	 */
-	ExecInitResultTupleSlot(estate, &nlstate->js.ps);
+	ExecInitResultTupleSlotTL(estate, &nlstate->js.ps);
+	ExecAssignProjectionInfo(&nlstate->js.ps, NULL);
+
+	/*
+	 * initialize child expressions
+	 */
+	nlstate->js.ps.qual =
+		ExecInitQual(node->join.plan.qual, (PlanState *) nlstate);
+	nlstate->js.jointype = node->join.jointype;
+	nlstate->js.joinqual =
+		ExecInitQual(node->join.joinqual, (PlanState *) nlstate);
 
 	/*
 	 * detect whether we need only consider the first matching inner tuple
@@ -339,12 +340,6 @@ ExecInitNestLoop(NestLoop *node, EState *estate, int eflags)
 	}
 
 	/*
-	 * initialize tuple type and projection info
-	 */
-	ExecAssignResultTypeFromTL(&nlstate->js.ps);
-	ExecAssignProjectionInfo(&nlstate->js.ps, NULL);
-
-	/*
 	 * finally, wipe the current outer tuple clean.
 	 */
 	nlstate->nl_NeedNewOuter = true;
diff --git a/src/backend/executor/nodeProjectSet.c b/src/backend/executor/nodeProjectSet.c
index 3b79993ade8..6d6ed38ceeb 100644
--- a/src/backend/executor/nodeProjectSet.c
+++ b/src/backend/executor/nodeProjectSet.c
@@ -244,14 +244,6 @@ ExecInitProjectSet(ProjectSet *node, EState *estate, int eflags)
 	ExecAssignExprContext(estate, &state->ps);
 
 	/*
-	 * tuple table initialization
-	 */
-	ExecInitResultTupleSlot(estate, &state->ps);
-
-	/* We don't support any qual on ProjectSet nodes */
-	Assert(node->plan.qual == NIL);
-
-	/*
 	 * initialize child nodes
 	 */
 	outerPlanState(state) = ExecInitNode(outerPlan(node), estate, eflags);
@@ -262,9 +254,9 @@ ExecInitProjectSet(ProjectSet *node, EState *estate, int eflags)
 	Assert(innerPlan(node) == NULL);
 
 	/*
-	 * initialize tuple type and projection info
+	 * tuple table and result type initialization
 	 */
-	ExecAssignResultTypeFromTL(&state->ps);
+	ExecInitResultTupleSlotTL(estate, &state->ps);
 
 	/* Create workspace for per-tlist-entry expr state & SRF-is-done state */
 	state->nelems = list_length(node->plan.targetlist);
@@ -301,6 +293,8 @@ ExecInitProjectSet(ProjectSet *node, EState *estate, int eflags)
 		off++;
 	}
 
+	/* We don't support any qual on ProjectSet nodes */
+	Assert(node->plan.qual == NIL);
 
 	/*
 	 * Create a memory context that ExecMakeFunctionResult can use to evaluate
diff --git a/src/backend/executor/nodeRecursiveunion.c b/src/backend/executor/nodeRecursiveunion.c
index ba48a69a3be..6b3ea5afb31 100644
--- a/src/backend/executor/nodeRecursiveunion.c
+++ b/src/backend/executor/nodeRecursiveunion.c
@@ -229,14 +229,13 @@ ExecInitRecursiveUnion(RecursiveUnion *node, EState *estate, int eflags)
 	 * RecursiveUnion nodes still have Result slots, which hold pointers to
 	 * tuples, so we have to initialize them.
 	 */
-	ExecInitResultTupleSlot(estate, &rustate->ps);
+	ExecInitResultTupleSlotTL(estate, &rustate->ps);
 
 	/*
-	 * Initialize result tuple type and projection info.  (Note: we have to
-	 * set up the result type before initializing child nodes, because
-	 * nodeWorktablescan.c expects it to be valid.)
+	 * Initialize result tuple type.  (Note: we have to set up the result type
+	 * before initializing child nodes, because nodeWorktablescan.c expects it
+	 * to be valid.)
 	 */
-	ExecAssignResultTypeFromTL(&rustate->ps);
 	rustate->ps.ps_ProjInfo = NULL;
 
 	/*
diff --git a/src/backend/executor/nodeResult.c b/src/backend/executor/nodeResult.c
index 5860d9c1ce6..e4418a29bba 100644
--- a/src/backend/executor/nodeResult.c
+++ b/src/backend/executor/nodeResult.c
@@ -205,19 +205,6 @@ ExecInitResult(Result *node, EState *estate, int eflags)
 	ExecAssignExprContext(estate, &resstate->ps);
 
 	/*
-	 * tuple table initialization
-	 */
-	ExecInitResultTupleSlot(estate, &resstate->ps);
-
-	/*
-	 * initialize child expressions
-	 */
-	resstate->ps.qual =
-		ExecInitQual(node->plan.qual, (PlanState *) resstate);
-	resstate->resconstantqual =
-		ExecInitQual((List *) node->resconstantqual, (PlanState *) resstate);
-
-	/*
 	 * initialize child nodes
 	 */
 	outerPlanState(resstate) = ExecInitNode(outerPlan(node), estate, eflags);
@@ -228,11 +215,19 @@ ExecInitResult(Result *node, EState *estate, int eflags)
 	Assert(innerPlan(node) == NULL);
 
 	/*
-	 * initialize tuple type and projection info
+	 * Initialize result slot, type and projection.
 	 */
-	ExecAssignResultTypeFromTL(&resstate->ps);
+	ExecInitResultTupleSlotTL(estate, &resstate->ps);
 	ExecAssignProjectionInfo(&resstate->ps, NULL);
 
+	/*
+	 * initialize child expressions
+	 */
+	resstate->ps.qual =
+		ExecInitQual(node->plan.qual, (PlanState *) resstate);
+	resstate->resconstantqual =
+		ExecInitQual((List *) node->resconstantqual, (PlanState *) resstate);
+
 	return resstate;
 }
 
diff --git a/src/backend/executor/nodeSamplescan.c b/src/backend/executor/nodeSamplescan.c
index e88cd187373..872d6e5735e 100644
--- a/src/backend/executor/nodeSamplescan.c
+++ b/src/backend/executor/nodeSamplescan.c
@@ -26,7 +26,6 @@
 #include "utils/rel.h"
 #include "utils/tqual.h"
 
-static void InitScanRelation(SampleScanState *node, EState *estate, int eflags);
 static TupleTableSlot *SampleNext(SampleScanState *node);
 static void tablesample_init(SampleScanState *scanstate);
 static HeapTuple tablesample_getnext(SampleScanState *scanstate);
@@ -107,35 +106,6 @@ ExecSampleScan(PlanState *pstate)
 }
 
 /* ----------------------------------------------------------------
- *		InitScanRelation
- *
- *		Set up to access the scan relation.
- * ----------------------------------------------------------------
- */
-static void
-InitScanRelation(SampleScanState *node, EState *estate, int eflags)
-{
-	Relation	currentRelation;
-
-	/*
-	 * get the relation object id from the relid'th entry in the range table,
-	 * open that relation and acquire appropriate lock on it.
-	 */
-	currentRelation = ExecOpenScanRelation(estate,
-										   ((SampleScan *) node->ss.ps.plan)->scan.scanrelid,
-										   eflags);
-
-	node->ss.ss_currentRelation = currentRelation;
-
-	/* we won't set up the HeapScanDesc till later */
-	node->ss.ss_currentScanDesc = NULL;
-
-	/* and report the scan tuple slot's rowtype */
-	ExecAssignScanType(&node->ss, RelationGetDescr(currentRelation));
-}
-
-
-/* ----------------------------------------------------------------
  *		ExecInitSampleScan
  * ----------------------------------------------------------------
  */
@@ -165,31 +135,39 @@ ExecInitSampleScan(SampleScan *node, EState *estate, int eflags)
 	ExecAssignExprContext(estate, &scanstate->ss.ps);
 
 	/*
-	 * initialize child expressions
+	 * Initialize scan relation.
+	 *
+	 * Get the relation object id from the relid'th entry in the range table,
+	 * open that relation and acquire appropriate lock on it.
 	 */
-	scanstate->ss.ps.qual =
-		ExecInitQual(node->scan.plan.qual, (PlanState *) scanstate);
+	scanstate->ss.ss_currentRelation =
+		ExecOpenScanRelation(estate,
+							 node->scan.scanrelid,
+							 eflags);
 
-	scanstate->args = ExecInitExprList(tsc->args, (PlanState *) scanstate);
-	scanstate->repeatable =
-		ExecInitExpr(tsc->repeatable, (PlanState *) scanstate);
+	/* we won't set up the HeapScanDesc till later */
+	scanstate->ss.ss_currentScanDesc = NULL;
 
-	/*
-	 * tuple table initialization
-	 */
-	ExecInitResultTupleSlot(estate, &scanstate->ss.ps);
-	ExecInitScanTupleSlot(estate, &scanstate->ss);
+	/* and create slot with appropriate rowtype */
+	ExecInitScanTupleSlot(estate, &scanstate->ss,
+						  RelationGetDescr(scanstate->ss.ss_currentRelation));
 
 	/*
-	 * initialize scan relation
+	 * Initialize result slot, type and projection.
+	 * tuple table and result tuple initialization
 	 */
-	InitScanRelation(scanstate, estate, eflags);
+	ExecInitResultTupleSlotTL(estate, &scanstate->ss.ps);
+	ExecAssignScanProjectionInfo(&scanstate->ss);
 
 	/*
-	 * Initialize result tuple type and projection info.
+	 * initialize child expressions
 	 */
-	ExecAssignResultTypeFromTL(&scanstate->ss.ps);
-	ExecAssignScanProjectionInfo(&scanstate->ss);
+	scanstate->ss.ps.qual =
+		ExecInitQual(node->scan.plan.qual, (PlanState *) scanstate);
+
+	scanstate->args = ExecInitExprList(tsc->args, (PlanState *) scanstate);
+	scanstate->repeatable =
+		ExecInitExpr(tsc->repeatable, (PlanState *) scanstate);
 
 	/*
 	 * If we don't have a REPEATABLE clause, select a random seed.  We want to
diff --git a/src/backend/executor/nodeSeqscan.c b/src/backend/executor/nodeSeqscan.c
index 58631378d5c..9db368922a3 100644
--- a/src/backend/executor/nodeSeqscan.c
+++ b/src/backend/executor/nodeSeqscan.c
@@ -32,7 +32,6 @@
 #include "executor/nodeSeqscan.h"
 #include "utils/rel.h"
 
-static void InitScanRelation(SeqScanState *node, EState *estate, int eflags);
 static TupleTableSlot *SeqNext(SeqScanState *node);
 
 /* ----------------------------------------------------------------
@@ -132,31 +131,6 @@ ExecSeqScan(PlanState *pstate)
 					(ExecScanRecheckMtd) SeqRecheck);
 }
 
-/* ----------------------------------------------------------------
- *		InitScanRelation
- *
- *		Set up to access the scan relation.
- * ----------------------------------------------------------------
- */
-static void
-InitScanRelation(SeqScanState *node, EState *estate, int eflags)
-{
-	Relation	currentRelation;
-
-	/*
-	 * get the relation object id from the relid'th entry in the range table,
-	 * open that relation and acquire appropriate lock on it.
-	 */
-	currentRelation = ExecOpenScanRelation(estate,
-										   ((SeqScan *) node->ss.ps.plan)->scanrelid,
-										   eflags);
-
-	node->ss.ss_currentRelation = currentRelation;
-
-	/* and report the scan tuple slot's rowtype */
-	ExecAssignScanType(&node->ss, RelationGetDescr(currentRelation));
-}
-
 
 /* ----------------------------------------------------------------
  *		ExecInitSeqScan
@@ -190,27 +164,31 @@ ExecInitSeqScan(SeqScan *node, EState *estate, int eflags)
 	ExecAssignExprContext(estate, &scanstate->ss.ps);
 
 	/*
-	 * initialize child expressions
+	 * Initialize scan relation.
+	 *
+	 * Get the relation object id from the relid'th entry in the range table,
+	 * open that relation and acquire appropriate lock on it.
 	 */
-	scanstate->ss.ps.qual =
-		ExecInitQual(node->plan.qual, (PlanState *) scanstate);
+	scanstate->ss.ss_currentRelation =
+		ExecOpenScanRelation(estate,
+							 node->scanrelid,
+							 eflags);
 
-	/*
-	 * tuple table initialization
-	 */
-	ExecInitResultTupleSlot(estate, &scanstate->ss.ps);
-	ExecInitScanTupleSlot(estate, &scanstate->ss);
+	/* and create slot with the appropriate rowtype */
+	ExecInitScanTupleSlot(estate, &scanstate->ss,
+						  RelationGetDescr(scanstate->ss.ss_currentRelation));
 
 	/*
-	 * initialize scan relation
+	 * Initialize result slot, type and projection.
 	 */
-	InitScanRelation(scanstate, estate, eflags);
+	ExecInitResultTupleSlotTL(estate, &scanstate->ss.ps);
+	ExecAssignScanProjectionInfo(&scanstate->ss);
 
 	/*
-	 * Initialize result tuple type and projection info.
+	 * initialize child expressions
 	 */
-	ExecAssignResultTypeFromTL(&scanstate->ss.ps);
-	ExecAssignScanProjectionInfo(&scanstate->ss);
+	scanstate->ss.ps.qual =
+		ExecInitQual(node->plan.qual, (PlanState *) scanstate);
 
 	return scanstate;
 }
diff --git a/src/backend/executor/nodeSetOp.c b/src/backend/executor/nodeSetOp.c
index eb5449fc3e2..3fa4a5fcc65 100644
--- a/src/backend/executor/nodeSetOp.c
+++ b/src/backend/executor/nodeSetOp.c
@@ -519,11 +519,6 @@ ExecInitSetOp(SetOp *node, EState *estate, int eflags)
 								  ALLOCSET_DEFAULT_SIZES);
 
 	/*
-	 * Tuple table initialization
-	 */
-	ExecInitResultTupleSlot(estate, &setopstate->ps);
-
-	/*
 	 * initialize child nodes
 	 *
 	 * If we are hashing then the child plan does not need to handle REWIND
@@ -535,10 +530,10 @@ ExecInitSetOp(SetOp *node, EState *estate, int eflags)
 	outerDesc = ExecGetResultType(outerPlanState(setopstate));
 
 	/*
-	 * setop nodes do no projections, so initialize projection info for this
-	 * node appropriately
+	 * Initialize result slot and type. Setop nodes do no projections, so
+	 * initialize projection info for this node appropriately.
 	 */
-	ExecAssignResultTypeFromTL(&setopstate->ps);
+	ExecInitResultTupleSlotTL(estate, &setopstate->ps);
 	setopstate->ps.ps_ProjInfo = NULL;
 
 	/*
diff --git a/src/backend/executor/nodeSort.c b/src/backend/executor/nodeSort.c
index d61c859fce6..73f16c9abaa 100644
--- a/src/backend/executor/nodeSort.c
+++ b/src/backend/executor/nodeSort.c
@@ -199,14 +199,6 @@ ExecInitSort(Sort *node, EState *estate, int eflags)
 	 */
 
 	/*
-	 * tuple table initialization
-	 *
-	 * sort nodes only return scan tuples from their sorted relation.
-	 */
-	ExecInitResultTupleSlot(estate, &sortstate->ss.ps);
-	ExecInitScanTupleSlot(estate, &sortstate->ss);
-
-	/*
 	 * initialize child nodes
 	 *
 	 * We shield the child node from the need to support REWIND, BACKWARD, or
@@ -217,11 +209,15 @@ ExecInitSort(Sort *node, EState *estate, int eflags)
 	outerPlanState(sortstate) = ExecInitNode(outerPlan(node), estate, eflags);
 
 	/*
-	 * initialize tuple type.  no need to initialize projection info because
+	 * Initialize scan slot and type.
+	 */
+	ExecCreateScanSlotFromOuterPlan(estate, &sortstate->ss);
+
+	/*
+	 * Initialize return slot and type. No need to initialize projection info because
 	 * this node doesn't do projections.
 	 */
-	ExecAssignResultTypeFromTL(&sortstate->ss.ps);
-	ExecAssignScanTypeFromOuterPlan(&sortstate->ss);
+	ExecInitResultTupleSlotTL(estate, &sortstate->ss.ps);
 	sortstate->ss.ps.ps_ProjInfo = NULL;
 
 	SO1_printf("ExecInitSort: %s\n",
diff --git a/src/backend/executor/nodeSubplan.c b/src/backend/executor/nodeSubplan.c
index 4927e212176..d5411500a2b 100644
--- a/src/backend/executor/nodeSubplan.c
+++ b/src/backend/executor/nodeSubplan.c
@@ -957,8 +957,7 @@ ExecInitSubPlan(SubPlan *subplan, PlanState *parent)
 		 * own innerecontext.
 		 */
 		tupDescLeft = ExecTypeFromTL(lefttlist, false);
-		slot = ExecInitExtraTupleSlot(estate);
-		ExecSetSlotDescriptor(slot, tupDescLeft);
+		slot = ExecInitExtraTupleSlot(estate, tupDescLeft);
 		sstate->projLeft = ExecBuildProjectionInfo(lefttlist,
 												   NULL,
 												   slot,
@@ -966,8 +965,7 @@ ExecInitSubPlan(SubPlan *subplan, PlanState *parent)
 												   NULL);
 
 		sstate->descRight = tupDescRight = ExecTypeFromTL(righttlist, false);
-		slot = ExecInitExtraTupleSlot(estate);
-		ExecSetSlotDescriptor(slot, tupDescRight);
+		slot = ExecInitExtraTupleSlot(estate, tupDescRight);
 		sstate->projRight = ExecBuildProjectionInfo(righttlist,
 													sstate->innerecontext,
 													slot,
diff --git a/src/backend/executor/nodeSubqueryscan.c b/src/backend/executor/nodeSubqueryscan.c
index 715a5b6a841..fa618847851 100644
--- a/src/backend/executor/nodeSubqueryscan.c
+++ b/src/backend/executor/nodeSubqueryscan.c
@@ -121,34 +121,28 @@ ExecInitSubqueryScan(SubqueryScan *node, EState *estate, int eflags)
 	ExecAssignExprContext(estate, &subquerystate->ss.ps);
 
 	/*
-	 * initialize child expressions
-	 */
-	subquerystate->ss.ps.qual =
-		ExecInitQual(node->scan.plan.qual, (PlanState *) subquerystate);
-
-	/*
-	 * tuple table initialization
-	 */
-	ExecInitResultTupleSlot(estate, &subquerystate->ss.ps);
-	ExecInitScanTupleSlot(estate, &subquerystate->ss);
-
-	/*
 	 * initialize subquery
 	 */
 	subquerystate->subplan = ExecInitNode(node->subplan, estate, eflags);
 
 	/*
-	 * Initialize scan tuple type (needed by ExecAssignScanProjectionInfo)
+	 * Initialize scan slot and type (needed by ExecInitResultTupleSlotTL)
 	 */
-	ExecAssignScanType(&subquerystate->ss,
-					   ExecGetResultType(subquerystate->subplan));
+	ExecInitScanTupleSlot(estate, &subquerystate->ss,
+						  ExecGetResultType(subquerystate->subplan));
 
 	/*
-	 * Initialize result tuple type and projection info.
+	 * Initialize result slot, type and projection.
 	 */
-	ExecAssignResultTypeFromTL(&subquerystate->ss.ps);
+	ExecInitResultTupleSlotTL(estate, &subquerystate->ss.ps);
 	ExecAssignScanProjectionInfo(&subquerystate->ss);
 
+	/*
+	 * initialize child expressions
+	 */
+	subquerystate->ss.ps.qual =
+		ExecInitQual(node->scan.plan.qual, (PlanState *) subquerystate);
+
 	return subquerystate;
 }
 
diff --git a/src/backend/executor/nodeTableFuncscan.c b/src/backend/executor/nodeTableFuncscan.c
index 3b609765d41..fed6f2b3a53 100644
--- a/src/backend/executor/nodeTableFuncscan.c
+++ b/src/backend/executor/nodeTableFuncscan.c
@@ -140,33 +140,27 @@ ExecInitTableFuncScan(TableFuncScan *node, EState *estate, int eflags)
 	ExecAssignExprContext(estate, &scanstate->ss.ps);
 
 	/*
-	 * initialize child expressions
-	 */
-	scanstate->ss.ps.qual =
-		ExecInitQual(node->scan.plan.qual, &scanstate->ss.ps);
-
-	/*
-	 * tuple table initialization
-	 */
-	ExecInitResultTupleSlot(estate, &scanstate->ss.ps);
-	ExecInitScanTupleSlot(estate, &scanstate->ss);
-
-	/*
 	 * initialize source tuple type
 	 */
 	tupdesc = BuildDescFromLists(tf->colnames,
 								 tf->coltypes,
 								 tf->coltypmods,
 								 tf->colcollations);
-
-	ExecAssignScanType(&scanstate->ss, tupdesc);
+	/* and the corresponding scan slot */
+	ExecInitScanTupleSlot(estate, &scanstate->ss, tupdesc);
 
 	/*
-	 * Initialize result tuple type and projection info.
+	 * Initialize result slot, type and projection.
 	 */
-	ExecAssignResultTypeFromTL(&scanstate->ss.ps);
+	ExecInitResultTupleSlotTL(estate, &scanstate->ss.ps);
 	ExecAssignScanProjectionInfo(&scanstate->ss);
 
+	/*
+	 * initialize child expressions
+	 */
+	scanstate->ss.ps.qual =
+		ExecInitQual(node->scan.plan.qual, &scanstate->ss.ps);
+
 	/* Only XMLTABLE is supported currently */
 	scanstate->routine = &XmlTableRoutine;
 
diff --git a/src/backend/executor/nodeTidscan.c b/src/backend/executor/nodeTidscan.c
index f2737bb7ef1..e207b1ffb51 100644
--- a/src/backend/executor/nodeTidscan.c
+++ b/src/backend/executor/nodeTidscan.c
@@ -531,20 +531,6 @@ ExecInitTidScan(TidScan *node, EState *estate, int eflags)
 	ExecAssignExprContext(estate, &tidstate->ss.ps);
 
 	/*
-	 * initialize child expressions
-	 */
-	tidstate->ss.ps.qual =
-		ExecInitQual(node->scan.plan.qual, (PlanState *) tidstate);
-
-	TidExprListCreate(tidstate);
-
-	/*
-	 * tuple table initialization
-	 */
-	ExecInitResultTupleSlot(estate, &tidstate->ss.ps);
-	ExecInitScanTupleSlot(estate, &tidstate->ss);
-
-	/*
 	 * mark tid list as not computed yet
 	 */
 	tidstate->tss_TidList = NULL;
@@ -562,15 +548,24 @@ ExecInitTidScan(TidScan *node, EState *estate, int eflags)
 	/*
 	 * get the scan type from the relation descriptor.
 	 */
-	ExecAssignScanType(&tidstate->ss, RelationGetDescr(currentRelation));
+	ExecInitScanTupleSlot(estate, &tidstate->ss,
+						  RelationGetDescr(currentRelation));
 
 	/*
-	 * Initialize result tuple type and projection info.
+	 * Initialize result slot, type and projection.
 	 */
-	ExecAssignResultTypeFromTL(&tidstate->ss.ps);
+	ExecInitResultTupleSlotTL(estate, &tidstate->ss.ps);
 	ExecAssignScanProjectionInfo(&tidstate->ss);
 
 	/*
+	 * initialize child expressions
+	 */
+	tidstate->ss.ps.qual =
+		ExecInitQual(node->scan.plan.qual, (PlanState *) tidstate);
+
+	TidExprListCreate(tidstate);
+
+	/*
 	 * all done.
 	 */
 	return tidstate;
diff --git a/src/backend/executor/nodeUnique.c b/src/backend/executor/nodeUnique.c
index 9f823c58e1a..05d65330a0e 100644
--- a/src/backend/executor/nodeUnique.c
+++ b/src/backend/executor/nodeUnique.c
@@ -133,20 +133,15 @@ ExecInitUnique(Unique *node, EState *estate, int eflags)
 	ExecAssignExprContext(estate, &uniquestate->ps);
 
 	/*
-	 * Tuple table initialization
-	 */
-	ExecInitResultTupleSlot(estate, &uniquestate->ps);
-
-	/*
 	 * then initialize outer plan
 	 */
 	outerPlanState(uniquestate) = ExecInitNode(outerPlan(node), estate, eflags);
 
 	/*
-	 * unique nodes do no projections, so initialize projection info for this
-	 * node appropriately
+	 * Initialize result slot and type. Unique nodes do no projections, so
+	 * initialize projection info for this node appropriately.
 	 */
-	ExecAssignResultTypeFromTL(&uniquestate->ps);
+	ExecInitResultTupleSlotTL(estate, &uniquestate->ps);
 	uniquestate->ps.ps_ProjInfo = NULL;
 
 	/*
diff --git a/src/backend/executor/nodeValuesscan.c b/src/backend/executor/nodeValuesscan.c
index c3d78b6295e..63b7e7ef5b8 100644
--- a/src/backend/executor/nodeValuesscan.c
+++ b/src/backend/executor/nodeValuesscan.c
@@ -248,23 +248,22 @@ ExecInitValuesScan(ValuesScan *node, EState *estate, int eflags)
 	ExecAssignExprContext(estate, planstate);
 
 	/*
-	 * tuple table initialization
+	 * Get info about values list, initialize scan slot with it.
 	 */
-	ExecInitResultTupleSlot(estate, &scanstate->ss.ps);
-	ExecInitScanTupleSlot(estate, &scanstate->ss);
+	tupdesc = ExecTypeFromExprList((List *) linitial(node->values_lists));
+	ExecInitScanTupleSlot(estate, &scanstate->ss, tupdesc);
 
 	/*
-	 * initialize child expressions
+	 * Initialize result slot, type and projection.
 	 */
-	scanstate->ss.ps.qual =
-		ExecInitQual(node->scan.plan.qual, (PlanState *) scanstate);
+	ExecInitResultTupleSlotTL(estate, &scanstate->ss.ps);
+	ExecAssignScanProjectionInfo(&scanstate->ss);
 
 	/*
-	 * get info about values list
+	 * initialize child expressions
 	 */
-	tupdesc = ExecTypeFromExprList((List *) linitial(node->values_lists));
-
-	ExecAssignScanType(&scanstate->ss, tupdesc);
+	scanstate->ss.ps.qual =
+		ExecInitQual(node->scan.plan.qual, (PlanState *) scanstate);
 
 	/*
 	 * Other node-specific setup
@@ -281,12 +280,6 @@ ExecInitValuesScan(ValuesScan *node, EState *estate, int eflags)
 		scanstate->exprlists[i++] = (List *) lfirst(vtl);
 	}
 
-	/*
-	 * Initialize result tuple type and projection info.
-	 */
-	ExecAssignResultTypeFromTL(&scanstate->ss.ps);
-	ExecAssignScanProjectionInfo(&scanstate->ss);
-
 	return scanstate;
 }
 
diff --git a/src/backend/executor/nodeWindowAgg.c b/src/backend/executor/nodeWindowAgg.c
index 1c807a82922..a56c3e89fd5 100644
--- a/src/backend/executor/nodeWindowAgg.c
+++ b/src/backend/executor/nodeWindowAgg.c
@@ -2288,30 +2288,6 @@ ExecInitWindowAgg(WindowAgg *node, EState *estate, int eflags)
 							  ALLOCSET_DEFAULT_SIZES);
 
 	/*
-	 * tuple table initialization
-	 */
-	ExecInitScanTupleSlot(estate, &winstate->ss);
-	ExecInitResultTupleSlot(estate, &winstate->ss.ps);
-	winstate->first_part_slot = ExecInitExtraTupleSlot(estate);
-	winstate->agg_row_slot = ExecInitExtraTupleSlot(estate);
-	winstate->temp_slot_1 = ExecInitExtraTupleSlot(estate);
-	winstate->temp_slot_2 = ExecInitExtraTupleSlot(estate);
-
-	/*
-	 * create frame head and tail slots only if needed (must match logic in
-	 * update_frameheadpos and update_frametailpos)
-	 */
-	winstate->framehead_slot = winstate->frametail_slot = NULL;
-
-	if (frameOptions & (FRAMEOPTION_RANGE | FRAMEOPTION_GROUPS))
-	{
-		if (!(frameOptions & FRAMEOPTION_START_UNBOUNDED_PRECEDING))
-			winstate->framehead_slot = ExecInitExtraTupleSlot(estate);
-		if (!(frameOptions & FRAMEOPTION_END_UNBOUNDED_FOLLOWING))
-			winstate->frametail_slot = ExecInitExtraTupleSlot(estate);
-	}
-
-	/*
 	 * WindowAgg nodes never have quals, since they can only occur at the
 	 * logical top level of a query (ie, after any WHERE or HAVING filters)
 	 */
@@ -2328,28 +2304,35 @@ ExecInitWindowAgg(WindowAgg *node, EState *estate, int eflags)
 	 * initialize source tuple type (which is also the tuple type that we'll
 	 * store in the tuplestore and use in all our working slots).
 	 */
-	ExecAssignScanTypeFromOuterPlan(&winstate->ss);
+	ExecCreateScanSlotFromOuterPlan(estate, &winstate->ss);
 	scanDesc = winstate->ss.ss_ScanTupleSlot->tts_tupleDescriptor;
 
-	ExecSetSlotDescriptor(winstate->first_part_slot,
-						  winstate->ss.ss_ScanTupleSlot->tts_tupleDescriptor);
-	ExecSetSlotDescriptor(winstate->agg_row_slot,
-						  winstate->ss.ss_ScanTupleSlot->tts_tupleDescriptor);
-	ExecSetSlotDescriptor(winstate->temp_slot_1,
-						  winstate->ss.ss_ScanTupleSlot->tts_tupleDescriptor);
-	ExecSetSlotDescriptor(winstate->temp_slot_2,
-						  winstate->ss.ss_ScanTupleSlot->tts_tupleDescriptor);
-	if (winstate->framehead_slot)
-		ExecSetSlotDescriptor(winstate->framehead_slot,
-							  winstate->ss.ss_ScanTupleSlot->tts_tupleDescriptor);
-	if (winstate->frametail_slot)
-		ExecSetSlotDescriptor(winstate->frametail_slot,
-							  winstate->ss.ss_ScanTupleSlot->tts_tupleDescriptor);
+	/*
+	 * tuple table initialization
+	 */
+	winstate->first_part_slot = ExecInitExtraTupleSlot(estate, scanDesc);
+	winstate->agg_row_slot = ExecInitExtraTupleSlot(estate, scanDesc);
+	winstate->temp_slot_1 = ExecInitExtraTupleSlot(estate, scanDesc);
+	winstate->temp_slot_2 = ExecInitExtraTupleSlot(estate, scanDesc);
+
+	/*
+	 * create frame head and tail slots only if needed (must match logic in
+	 * update_frameheadpos and update_frametailpos)
+	 */
+	winstate->framehead_slot = winstate->frametail_slot = NULL;
+
+	if (frameOptions & (FRAMEOPTION_RANGE | FRAMEOPTION_GROUPS))
+	{
+		if (!(frameOptions & FRAMEOPTION_START_UNBOUNDED_PRECEDING))
+			winstate->framehead_slot = ExecInitExtraTupleSlot(estate, scanDesc);
+		if (!(frameOptions & FRAMEOPTION_END_UNBOUNDED_FOLLOWING))
+			winstate->frametail_slot = ExecInitExtraTupleSlot(estate, scanDesc);
+	}
 
 	/*
-	 * Initialize result tuple type and projection info.
+	 * Initialize result slot, type and projection.
 	 */
-	ExecAssignResultTypeFromTL(&winstate->ss.ps);
+	ExecInitResultTupleSlotTL(estate, &winstate->ss.ps);
 	ExecAssignProjectionInfo(&winstate->ss.ps, NULL);
 
 	/* Set up data for comparing tuples */
diff --git a/src/backend/executor/nodeWorktablescan.c b/src/backend/executor/nodeWorktablescan.c
index 66d2111bd9f..2ff9a215b12 100644
--- a/src/backend/executor/nodeWorktablescan.c
+++ b/src/backend/executor/nodeWorktablescan.c
@@ -157,21 +157,21 @@ ExecInitWorkTableScan(WorkTableScan *node, EState *estate, int eflags)
 	ExecAssignExprContext(estate, &scanstate->ss.ps);
 
 	/*
-	 * initialize child expressions
+	 * tuple table initialization
 	 */
-	scanstate->ss.ps.qual =
-		ExecInitQual(node->scan.plan.qual, (PlanState *) scanstate);
+	ExecInitResultTupleSlotTL(estate, &scanstate->ss.ps);
+	ExecInitScanTupleSlot(estate, &scanstate->ss, NULL);
 
 	/*
-	 * tuple table initialization
+	 * initialize child expressions
 	 */
-	ExecInitResultTupleSlot(estate, &scanstate->ss.ps);
-	ExecInitScanTupleSlot(estate, &scanstate->ss);
+	scanstate->ss.ps.qual =
+		ExecInitQual(node->scan.plan.qual, (PlanState *) scanstate);
 
 	/*
-	 * Initialize result tuple type, but not yet projection info.
+	 * Do not yet initialize projection info, see ExecWorkTableScan() for
+	 * details.
 	 */
-	ExecAssignResultTypeFromTL(&scanstate->ss.ps);
 
 	return scanstate;
 }
diff --git a/src/backend/replication/logical/worker.c b/src/backend/replication/logical/worker.c
index 83c69092ae8..04985c9f91d 100644
--- a/src/backend/replication/logical/worker.c
+++ b/src/backend/replication/logical/worker.c
@@ -208,7 +208,7 @@ create_estate_for_relation(LogicalRepRelMapEntry *rel)
 
 	/* Triggers might need a slot */
 	if (resultRelInfo->ri_TrigDesc)
-		estate->es_trig_tuple_slot = ExecInitExtraTupleSlot(estate);
+		estate->es_trig_tuple_slot = ExecInitExtraTupleSlot(estate, NULL);
 
 	/* Prepare to catch AFTER triggers. */
 	AfterTriggerBeginQuery();
@@ -585,8 +585,8 @@ apply_handle_insert(StringInfo s)
 
 	/* Initialize the executor state. */
 	estate = create_estate_for_relation(rel);
-	remoteslot = ExecInitExtraTupleSlot(estate);
-	ExecSetSlotDescriptor(remoteslot, RelationGetDescr(rel->localrel));
+	remoteslot = ExecInitExtraTupleSlot(estate,
+										RelationGetDescr(rel->localrel));
 
 	/* Process and store remote tuple in the slot */
 	oldctx = MemoryContextSwitchTo(GetPerTupleMemoryContext(estate));
@@ -689,10 +689,10 @@ apply_handle_update(StringInfo s)
 
 	/* Initialize the executor state. */
 	estate = create_estate_for_relation(rel);
-	remoteslot = ExecInitExtraTupleSlot(estate);
-	ExecSetSlotDescriptor(remoteslot, RelationGetDescr(rel->localrel));
-	localslot = ExecInitExtraTupleSlot(estate);
-	ExecSetSlotDescriptor(localslot, RelationGetDescr(rel->localrel));
+	remoteslot = ExecInitExtraTupleSlot(estate,
+										RelationGetDescr(rel->localrel));
+	localslot = ExecInitExtraTupleSlot(estate,
+									   RelationGetDescr(rel->localrel));
 	EvalPlanQualInit(&epqstate, estate, NULL, NIL, -1);
 
 	PushActiveSnapshot(GetTransactionSnapshot());
@@ -807,10 +807,10 @@ apply_handle_delete(StringInfo s)
 
 	/* Initialize the executor state. */
 	estate = create_estate_for_relation(rel);
-	remoteslot = ExecInitExtraTupleSlot(estate);
-	ExecSetSlotDescriptor(remoteslot, RelationGetDescr(rel->localrel));
-	localslot = ExecInitExtraTupleSlot(estate);
-	ExecSetSlotDescriptor(localslot, RelationGetDescr(rel->localrel));
+	remoteslot = ExecInitExtraTupleSlot(estate,
+										RelationGetDescr(rel->localrel));
+	localslot = ExecInitExtraTupleSlot(estate,
+									   RelationGetDescr(rel->localrel));
 	EvalPlanQualInit(&epqstate, estate, NULL, NIL, -1);
 
 	PushActiveSnapshot(GetTransactionSnapshot());
diff --git a/src/include/executor/executor.h b/src/include/executor/executor.h
index 621e7c3dc46..45a077a949c 100644
--- a/src/include/executor/executor.h
+++ b/src/include/executor/executor.h
@@ -431,9 +431,10 @@ extern void ExecScanReScan(ScanState *node);
 /*
  * prototypes from functions in execTuples.c
  */
-extern void ExecInitResultTupleSlot(EState *estate, PlanState *planstate);
-extern void ExecInitScanTupleSlot(EState *estate, ScanState *scanstate);
-extern TupleTableSlot *ExecInitExtraTupleSlot(EState *estate);
+extern void ExecInitResultTupleSlotTL(EState *estate, PlanState *planstate);
+extern void ExecInitScanTupleSlot(EState *estate, ScanState *scanstate, TupleDesc tupleDesc);
+extern TupleTableSlot *ExecInitExtraTupleSlot(EState *estate,
+					  TupleDesc tupleDesc);
 extern TupleTableSlot *ExecInitNullTupleSlot(EState *estate,
 					  TupleDesc tupType);
 extern TupleDesc ExecTypeFromTL(List *targetList, bool hasoid);
@@ -502,8 +503,6 @@ extern ExprContext *MakePerTupleExprContext(EState *estate);
 	} while (0)
 
 extern void ExecAssignExprContext(EState *estate, PlanState *planstate);
-extern void ExecAssignResultType(PlanState *planstate, TupleDesc tupDesc);
-extern void ExecAssignResultTypeFromTL(PlanState *planstate);
 extern TupleDesc ExecGetResultType(PlanState *planstate);
 extern void ExecAssignProjectionInfo(PlanState *planstate,
 						 TupleDesc inputDesc);
@@ -511,7 +510,7 @@ extern void ExecConditionalAssignProjectionInfo(PlanState *planstate,
 									TupleDesc inputDesc, Index varno);
 extern void ExecFreeExprContext(PlanState *planstate);
 extern void ExecAssignScanType(ScanState *scanstate, TupleDesc tupDesc);
-extern void ExecAssignScanTypeFromOuterPlan(ScanState *scanstate);
+extern void ExecCreateScanSlotFromOuterPlan(EState *estate, ScanState *scanstate);
 
 extern bool ExecRelationIsTargetRelation(EState *estate, Index scanrelid);
 
diff --git a/src/include/executor/tuptable.h b/src/include/executor/tuptable.h
index 5b54834d33e..8be0d5edc29 100644
--- a/src/include/executor/tuptable.h
+++ b/src/include/executor/tuptable.h
@@ -127,6 +127,7 @@ typedef struct TupleTableSlot
 	MinimalTuple tts_mintuple;	/* minimal tuple, or NULL if none */
 	HeapTupleData tts_minhdr;	/* workspace for minimal-tuple-only case */
 	long		tts_off;		/* saved state for slot_deform_tuple */
+	bool		tts_fixedTupleDescriptor; /* descriptor can't be changed */
 } TupleTableSlot;
 
 #define TTS_HAS_PHYSICAL_TUPLE(slot)  \
@@ -139,8 +140,8 @@ typedef struct TupleTableSlot
 	((slot) == NULL || (slot)->tts_isempty)
 
 /* in executor/execTuples.c */
-extern TupleTableSlot *MakeTupleTableSlot(void);
-extern TupleTableSlot *ExecAllocTableSlot(List **tupleTable);
+extern TupleTableSlot *MakeTupleTableSlot(TupleDesc desc);
+extern TupleTableSlot *ExecAllocTableSlot(List **tupleTable, TupleDesc desc);
 extern void ExecResetTupleTable(List *tupleTable, bool shouldFree);
 extern TupleTableSlot *MakeSingleTupleTableSlot(TupleDesc tupdesc);
 extern void ExecDropSingleTupleTableSlot(TupleTableSlot *slot);