From: Andres Freund <andres@anarazel.de>
Date: Mon, 17 Jul 2017 07:33:49 +0000 (-0700)
Subject: Move ExecProcNode from dispatch to function pointer based model.
X-Git-Tag: REL_10_BETA3~65
X-Git-Url: http://git.postgresql.org/gitweb/?a=commitdiff_plain;h=cc9f08b6b813e30789100b6b34110d8be1090ba0;p=postgresql.git

Move ExecProcNode from dispatch to function pointer based model.

This allows us to add stack-depth checks the first time an executor
node is called, and skip that overhead on following
calls. Additionally it yields a nice speedup.

While it'd probably have been a good idea to have that check all
along, it has become more important after the new expression
evaluation framework in b8d7f053c5c2bf2a7e - there's no stack depth
check in common paths anymore now. We previously relied on
ExecEvalExpr() being executed somewhere.

We should move towards that model for further routines, but as this is
required for v10, it seems better to only do the necessary (which
already is quite large).

Author: Andres Freund, Tom Lane
Reported-By: Julien Rouhaud
Discussion:
    https://postgr.es/m/22833.1490390175@sss.pgh.pa.us
    https://postgr.es/m/b0af9eaa-130c-60d0-9e4e-7a135b1e0c76@dalibo.com
---

diff --git a/src/backend/executor/execProcnode.c b/src/backend/executor/execProcnode.c
index 20fd9f822ed..396920c0a23 100644
--- a/src/backend/executor/execProcnode.c
+++ b/src/backend/executor/execProcnode.c
@@ -17,15 +17,10 @@
  *-------------------------------------------------------------------------
  */
 /*
- *	 INTERFACE ROUTINES
- *		ExecInitNode	-		initialize a plan node and its subplans
- *		ExecProcNode	-		get a tuple by executing the plan node
- *		ExecEndNode		-		shut down a plan node and its subplans
- *
  *	 NOTES
  *		This used to be three files.  It is now all combined into
- *		one file so that it is easier to keep ExecInitNode, ExecProcNode,
- *		and ExecEndNode in sync when new nodes are added.
+ *		one file so that it is easier to keep the dispatch routines
+ *		in sync when new nodes are added.
  *
  *	 EXAMPLE
  *		Suppose we want the age of the manager of the shoe department and
@@ -122,6 +117,10 @@
 #include "miscadmin.h"
 
 
+static TupleTableSlot *ExecProcNodeFirst(PlanState *node);
+static TupleTableSlot *ExecProcNodeInstr(PlanState *node);
+
+
 /* ------------------------------------------------------------------------
  *		ExecInitNode
  *
@@ -149,6 +148,13 @@ ExecInitNode(Plan *node, EState *estate, int eflags)
 	if (node == NULL)
 		return NULL;
 
+	/*
+	 * Make sure there's enough stack available. Need to check here, in
+	 * addition to ExecProcNode() (via ExecProcNodeFirst()), to ensure the
+	 * stack isn't overrun while initializing the node tree.
+	 */
+	check_stack_depth();
+
 	switch (nodeTag(node))
 	{
 			/*
@@ -364,6 +370,13 @@ ExecInitNode(Plan *node, EState *estate, int eflags)
 			break;
 	}
 
+	/*
+	 * Add a wrapper around the ExecProcNode callback that checks stack depth
+	 * during the first execution.
+	 */
+	result->ExecProcNodeReal = result->ExecProcNode;
+	result->ExecProcNode = ExecProcNodeFirst;
+
 	/*
 	 * Initialize any initPlans present in this node.  The planner put them in
 	 * a separate list for us.
@@ -388,195 +401,51 @@ ExecInitNode(Plan *node, EState *estate, int eflags)
 }
 
 
-/* ----------------------------------------------------------------
- *		ExecProcNode
- *
- *		Execute the given node to return a(nother) tuple.
- * ----------------------------------------------------------------
+/*
+ * ExecProcNode wrapper that performs some one-time checks, before calling
+ * the relevant node method (possibly via an instrumentation wrapper).
  */
-TupleTableSlot *
-ExecProcNode(PlanState *node)
+static TupleTableSlot *
+ExecProcNodeFirst(PlanState *node)
 {
-	TupleTableSlot *result;
-
-	if (node->chgParam != NULL) /* something changed */
-		ExecReScan(node);		/* let ReScan handle this */
+	/*
+	 * Perform stack depth check during the first execution of the node.  We
+	 * only do so the first time round because it turns out to not be cheap on
+	 * some common architectures (eg. x86).  This relies on the assumption that
+	 * ExecProcNode calls for a given plan node will always be made at roughly
+	 * the same stack depth.
+	 */
+	check_stack_depth();
 
+	/*
+	 * If instrumentation is required, change the wrapper to one that just
+	 * does instrumentation.  Otherwise we can dispense with all wrappers and
+	 * have ExecProcNode() directly call the relevant function from now on.
+	 */
 	if (node->instrument)
-		InstrStartNode(node->instrument);
-
-	switch (nodeTag(node))
-	{
-			/*
-			 * control nodes
-			 */
-		case T_ResultState:
-			result = ExecResult((ResultState *) node);
-			break;
-
-		case T_ProjectSetState:
-			result = ExecProjectSet((ProjectSetState *) node);
-			break;
-
-		case T_ModifyTableState:
-			result = ExecModifyTable((ModifyTableState *) node);
-			break;
-
-		case T_AppendState:
-			result = ExecAppend((AppendState *) node);
-			break;
-
-		case T_MergeAppendState:
-			result = ExecMergeAppend((MergeAppendState *) node);
-			break;
-
-		case T_RecursiveUnionState:
-			result = ExecRecursiveUnion((RecursiveUnionState *) node);
-			break;
-
-			/* BitmapAndState does not yield tuples */
-
-			/* BitmapOrState does not yield tuples */
-
-			/*
-			 * scan nodes
-			 */
-		case T_SeqScanState:
-			result = ExecSeqScan((SeqScanState *) node);
-			break;
-
-		case T_SampleScanState:
-			result = ExecSampleScan((SampleScanState *) node);
-			break;
-
-		case T_IndexScanState:
-			result = ExecIndexScan((IndexScanState *) node);
-			break;
-
-		case T_IndexOnlyScanState:
-			result = ExecIndexOnlyScan((IndexOnlyScanState *) node);
-			break;
-
-			/* BitmapIndexScanState does not yield tuples */
-
-		case T_BitmapHeapScanState:
-			result = ExecBitmapHeapScan((BitmapHeapScanState *) node);
-			break;
-
-		case T_TidScanState:
-			result = ExecTidScan((TidScanState *) node);
-			break;
-
-		case T_SubqueryScanState:
-			result = ExecSubqueryScan((SubqueryScanState *) node);
-			break;
-
-		case T_FunctionScanState:
-			result = ExecFunctionScan((FunctionScanState *) node);
-			break;
-
-		case T_TableFuncScanState:
-			result = ExecTableFuncScan((TableFuncScanState *) node);
-			break;
-
-		case T_ValuesScanState:
-			result = ExecValuesScan((ValuesScanState *) node);
-			break;
-
-		case T_CteScanState:
-			result = ExecCteScan((CteScanState *) node);
-			break;
-
-		case T_NamedTuplestoreScanState:
-			result = ExecNamedTuplestoreScan((NamedTuplestoreScanState *) node);
-			break;
-
-		case T_WorkTableScanState:
-			result = ExecWorkTableScan((WorkTableScanState *) node);
-			break;
-
-		case T_ForeignScanState:
-			result = ExecForeignScan((ForeignScanState *) node);
-			break;
-
-		case T_CustomScanState:
-			result = ExecCustomScan((CustomScanState *) node);
-			break;
-
-			/*
-			 * join nodes
-			 */
-		case T_NestLoopState:
-			result = ExecNestLoop((NestLoopState *) node);
-			break;
-
-		case T_MergeJoinState:
-			result = ExecMergeJoin((MergeJoinState *) node);
-			break;
-
-		case T_HashJoinState:
-			result = ExecHashJoin((HashJoinState *) node);
-			break;
-
-			/*
-			 * materialization nodes
-			 */
-		case T_MaterialState:
-			result = ExecMaterial((MaterialState *) node);
-			break;
-
-		case T_SortState:
-			result = ExecSort((SortState *) node);
-			break;
-
-		case T_GroupState:
-			result = ExecGroup((GroupState *) node);
-			break;
+		node->ExecProcNode = ExecProcNodeInstr;
+	else
+		node->ExecProcNode = node->ExecProcNodeReal;
 
-		case T_AggState:
-			result = ExecAgg((AggState *) node);
-			break;
-
-		case T_WindowAggState:
-			result = ExecWindowAgg((WindowAggState *) node);
-			break;
-
-		case T_UniqueState:
-			result = ExecUnique((UniqueState *) node);
-			break;
-
-		case T_GatherState:
-			result = ExecGather((GatherState *) node);
-			break;
-
-		case T_GatherMergeState:
-			result = ExecGatherMerge((GatherMergeState *) node);
-			break;
-
-		case T_HashState:
-			result = ExecHash((HashState *) node);
-			break;
+	return node->ExecProcNode(node);
+}
 
-		case T_SetOpState:
-			result = ExecSetOp((SetOpState *) node);
-			break;
 
-		case T_LockRowsState:
-			result = ExecLockRows((LockRowsState *) node);
-			break;
+/*
+ * ExecProcNode wrapper that performs instrumentation calls.  By keeping
+ * this a separate function, we avoid overhead in the normal case where
+ * no instrumentation is wanted.
+ */
+static TupleTableSlot *
+ExecProcNodeInstr(PlanState *node)
+{
+	TupleTableSlot *result;
 
-		case T_LimitState:
-			result = ExecLimit((LimitState *) node);
-			break;
+	InstrStartNode(node->instrument);
 
-		default:
-			elog(ERROR, "unrecognized node type: %d", (int) nodeTag(node));
-			result = NULL;
-			break;
-	}
+	result = node->ExecProcNodeReal(node);
 
-	if (node->instrument)
-		InstrStopNode(node->instrument, TupIsNull(result) ? 0.0 : 1.0);
+	InstrStopNode(node->instrument, TupIsNull(result) ? 0.0 : 1.0);
 
 	return result;
 }
@@ -600,6 +469,8 @@ MultiExecProcNode(PlanState *node)
 {
 	Node	   *result;
 
+	check_stack_depth();
+
 	CHECK_FOR_INTERRUPTS();
 
 	if (node->chgParam != NULL) /* something changed */
@@ -657,6 +528,13 @@ ExecEndNode(PlanState *node)
 	if (node == NULL)
 		return;
 
+	/*
+	 * Make sure there's enough stack available. Need to check here, in
+	 * addition to ExecProcNode() (via ExecProcNodeFirst()), because it's not
+	 * guaranteed that ExecProcNode() is reached for all nodes.
+	 */
+	check_stack_depth();
+
 	if (node->chgParam != NULL)
 	{
 		bms_free(node->chgParam);
@@ -855,6 +733,8 @@ ExecShutdownNode(PlanState *node)
 	if (node == NULL)
 		return false;
 
+	check_stack_depth();
+
 	planstate_tree_walker(node, ExecShutdownNode, NULL);
 
 	switch (nodeTag(node))
diff --git a/src/backend/executor/nodeAgg.c b/src/backend/executor/nodeAgg.c
index 377916dae75..6a26773a49f 100644
--- a/src/backend/executor/nodeAgg.c
+++ b/src/backend/executor/nodeAgg.c
@@ -2099,9 +2099,10 @@ lookup_hash_entries(AggState *aggstate)
  *	  stored in the expression context to be used when ExecProject evaluates
  *	  the result tuple.
  */
-TupleTableSlot *
-ExecAgg(AggState *node)
+static TupleTableSlot *
+ExecAgg(PlanState *pstate)
 {
+	AggState   *node = castNode(AggState, pstate);
 	TupleTableSlot *result = NULL;
 
 	CHECK_FOR_INTERRUPTS();
@@ -2695,6 +2696,7 @@ ExecInitAgg(Agg *node, EState *estate, int eflags)
 	aggstate = makeNode(AggState);
 	aggstate->ss.ps.plan = (Plan *) node;
 	aggstate->ss.ps.state = estate;
+	aggstate->ss.ps.ExecProcNode = ExecAgg;
 
 	aggstate->aggs = NIL;
 	aggstate->numaggs = 0;
diff --git a/src/backend/executor/nodeAppend.c b/src/backend/executor/nodeAppend.c
index 58045e05e5d..bed9bb87138 100644
--- a/src/backend/executor/nodeAppend.c
+++ b/src/backend/executor/nodeAppend.c
@@ -61,6 +61,7 @@
 #include "executor/nodeAppend.h"
 #include "miscadmin.h"
 
+static TupleTableSlot *ExecAppend(PlanState *pstate);
 static bool exec_append_initialize_next(AppendState *appendstate);
 
 
@@ -147,6 +148,7 @@ ExecInitAppend(Append *node, EState *estate, int eflags)
 	 */
 	appendstate->ps.plan = (Plan *) node;
 	appendstate->ps.state = estate;
+	appendstate->ps.ExecProcNode = ExecAppend;
 	appendstate->appendplans = appendplanstates;
 	appendstate->as_nplans = nplans;
 
@@ -197,9 +199,11 @@ ExecInitAppend(Append *node, EState *estate, int eflags)
  *		Handles iteration over multiple subplans.
  * ----------------------------------------------------------------
  */
-TupleTableSlot *
-ExecAppend(AppendState *node)
+static TupleTableSlot *
+ExecAppend(PlanState *pstate)
 {
+	AppendState *node = castNode(AppendState, pstate);
+
 	for (;;)
 	{
 		PlanState  *subnode;
diff --git a/src/backend/executor/nodeBitmapAnd.c b/src/backend/executor/nodeBitmapAnd.c
index e4eb028ff9c..1c5c312c954 100644
--- a/src/backend/executor/nodeBitmapAnd.c
+++ b/src/backend/executor/nodeBitmapAnd.c
@@ -32,6 +32,19 @@
 #include "executor/nodeBitmapAnd.h"
 
 
+/* ----------------------------------------------------------------
+ *		ExecBitmapAnd
+ *
+ *		stub for pro forma compliance
+ * ----------------------------------------------------------------
+ */
+static TupleTableSlot *
+ExecBitmapAnd(PlanState *pstate)
+{
+	elog(ERROR, "BitmapAnd node does not support ExecProcNode call convention");
+	return NULL;
+}
+
 /* ----------------------------------------------------------------
  *		ExecInitBitmapAnd
  *
@@ -63,6 +76,7 @@ ExecInitBitmapAnd(BitmapAnd *node, EState *estate, int eflags)
 	 */
 	bitmapandstate->ps.plan = (Plan *) node;
 	bitmapandstate->ps.state = estate;
+	bitmapandstate->ps.ExecProcNode = ExecBitmapAnd;
 	bitmapandstate->bitmapplans = bitmapplanstates;
 	bitmapandstate->nplans = nplans;
 
diff --git a/src/backend/executor/nodeBitmapHeapscan.c b/src/backend/executor/nodeBitmapHeapscan.c
index cf109d5049f..79f534e4e92 100644
--- a/src/backend/executor/nodeBitmapHeapscan.c
+++ b/src/backend/executor/nodeBitmapHeapscan.c
@@ -665,9 +665,11 @@ BitmapHeapRecheck(BitmapHeapScanState *node, TupleTableSlot *slot)
  *		ExecBitmapHeapScan(node)
  * ----------------------------------------------------------------
  */
-TupleTableSlot *
-ExecBitmapHeapScan(BitmapHeapScanState *node)
+static TupleTableSlot *
+ExecBitmapHeapScan(PlanState *pstate)
 {
+	BitmapHeapScanState *node = castNode(BitmapHeapScanState, pstate);
+
 	return ExecScan(&node->ss,
 					(ExecScanAccessMtd) BitmapHeapNext,
 					(ExecScanRecheckMtd) BitmapHeapRecheck);
@@ -815,6 +817,7 @@ ExecInitBitmapHeapScan(BitmapHeapScan *node, EState *estate, int eflags)
 	scanstate = makeNode(BitmapHeapScanState);
 	scanstate->ss.ps.plan = (Plan *) node;
 	scanstate->ss.ps.state = estate;
+	scanstate->ss.ps.ExecProcNode = ExecBitmapHeapScan;
 
 	scanstate->tbm = NULL;
 	scanstate->tbmiterator = NULL;
diff --git a/src/backend/executor/nodeBitmapIndexscan.c b/src/backend/executor/nodeBitmapIndexscan.c
index 2411a2e5c1a..6feb70f4ae3 100644
--- a/src/backend/executor/nodeBitmapIndexscan.c
+++ b/src/backend/executor/nodeBitmapIndexscan.c
@@ -28,6 +28,19 @@
 #include "utils/memutils.h"
 
 
+/* ----------------------------------------------------------------
+ *		ExecBitmapIndexScan
+ *
+ *		stub for pro forma compliance
+ * ----------------------------------------------------------------
+ */
+static TupleTableSlot *
+ExecBitmapIndexScan(PlanState *pstate)
+{
+	elog(ERROR, "BitmapIndexScan node does not support ExecProcNode call convention");
+	return NULL;
+}
+
 /* ----------------------------------------------------------------
  *		MultiExecBitmapIndexScan(node)
  * ----------------------------------------------------------------
@@ -208,6 +221,7 @@ ExecInitBitmapIndexScan(BitmapIndexScan *node, EState *estate, int eflags)
 	indexstate = makeNode(BitmapIndexScanState);
 	indexstate->ss.ps.plan = (Plan *) node;
 	indexstate->ss.ps.state = estate;
+	indexstate->ss.ps.ExecProcNode = ExecBitmapIndexScan;
 
 	/* normally we don't make the result bitmap till runtime */
 	indexstate->biss_result = NULL;
diff --git a/src/backend/executor/nodeBitmapOr.c b/src/backend/executor/nodeBitmapOr.c
index 4f0ddc6dffd..66a7a89a8b7 100644
--- a/src/backend/executor/nodeBitmapOr.c
+++ b/src/backend/executor/nodeBitmapOr.c
@@ -33,6 +33,19 @@
 #include "miscadmin.h"
 
 
+/* ----------------------------------------------------------------
+ *		ExecBitmapOr
+ *
+ *		stub for pro forma compliance
+ * ----------------------------------------------------------------
+ */
+static TupleTableSlot *
+ExecBitmapOr(PlanState *pstate)
+{
+	elog(ERROR, "BitmapOr node does not support ExecProcNode call convention");
+	return NULL;
+}
+
 /* ----------------------------------------------------------------
  *		ExecInitBitmapOr
  *
@@ -64,6 +77,7 @@ ExecInitBitmapOr(BitmapOr *node, EState *estate, int eflags)
 	 */
 	bitmaporstate->ps.plan = (Plan *) node;
 	bitmaporstate->ps.state = estate;
+	bitmaporstate->ps.ExecProcNode = ExecBitmapOr;
 	bitmaporstate->bitmapplans = bitmapplanstates;
 	bitmaporstate->nplans = nplans;
 
diff --git a/src/backend/executor/nodeCtescan.c b/src/backend/executor/nodeCtescan.c
index bed7949c5a0..79676ca9787 100644
--- a/src/backend/executor/nodeCtescan.c
+++ b/src/backend/executor/nodeCtescan.c
@@ -149,9 +149,11 @@ CteScanRecheck(CteScanState *node, TupleTableSlot *slot)
  *		access method functions.
  * ----------------------------------------------------------------
  */
-TupleTableSlot *
-ExecCteScan(CteScanState *node)
+static TupleTableSlot *
+ExecCteScan(PlanState *pstate)
 {
+	CteScanState *node = castNode(CteScanState, pstate);
+
 	return ExecScan(&node->ss,
 					(ExecScanAccessMtd) CteScanNext,
 					(ExecScanRecheckMtd) CteScanRecheck);
@@ -191,6 +193,7 @@ ExecInitCteScan(CteScan *node, EState *estate, int eflags)
 	scanstate = makeNode(CteScanState);
 	scanstate->ss.ps.plan = (Plan *) node;
 	scanstate->ss.ps.state = estate;
+	scanstate->ss.ps.ExecProcNode = ExecCteScan;
 	scanstate->eflags = eflags;
 	scanstate->cte_table = NULL;
 	scanstate->eof_cte = false;
diff --git a/src/backend/executor/nodeCustom.c b/src/backend/executor/nodeCustom.c
index fc15974a2d0..fb7645b1f46 100644
--- a/src/backend/executor/nodeCustom.c
+++ b/src/backend/executor/nodeCustom.c
@@ -21,6 +21,10 @@
 #include "utils/memutils.h"
 #include "utils/rel.h"
 
+
+static TupleTableSlot *ExecCustomScan(PlanState *pstate);
+
+
 CustomScanState *
 ExecInitCustomScan(CustomScan *cscan, EState *estate, int eflags)
 {
@@ -45,6 +49,7 @@ ExecInitCustomScan(CustomScan *cscan, EState *estate, int eflags)
 	/* fill up fields of ScanState */
 	css->ss.ps.plan = &cscan->scan.plan;
 	css->ss.ps.state = estate;
+	css->ss.ps.ExecProcNode = ExecCustomScan;
 
 	/* create expression context for node */
 	ExecAssignExprContext(estate, &css->ss.ps);
@@ -102,9 +107,11 @@ ExecInitCustomScan(CustomScan *cscan, EState *estate, int eflags)
 	return css;
 }
 
-TupleTableSlot *
-ExecCustomScan(CustomScanState *node)
+static TupleTableSlot *
+ExecCustomScan(PlanState *pstate)
 {
+	CustomScanState *node = castNode(CustomScanState, pstate);
+
 	CHECK_FOR_INTERRUPTS();
 
 	Assert(node->methods->ExecCustomScan != NULL);
diff --git a/src/backend/executor/nodeForeignscan.c b/src/backend/executor/nodeForeignscan.c
index 9cde112554b..140e82ef5e4 100644
--- a/src/backend/executor/nodeForeignscan.c
+++ b/src/backend/executor/nodeForeignscan.c
@@ -113,10 +113,12 @@ ForeignRecheck(ForeignScanState *node, TupleTableSlot *slot)
  *		access method functions.
  * ----------------------------------------------------------------
  */
-TupleTableSlot *
-ExecForeignScan(ForeignScanState *node)
+static TupleTableSlot *
+ExecForeignScan(PlanState *pstate)
 {
-	return ExecScan((ScanState *) node,
+	ForeignScanState *node = castNode(ForeignScanState, pstate);
+
+	return ExecScan(&node->ss,
 					(ExecScanAccessMtd) ForeignNext,
 					(ExecScanRecheckMtd) ForeignRecheck);
 }
@@ -144,6 +146,7 @@ ExecInitForeignScan(ForeignScan *node, EState *estate, int eflags)
 	scanstate = makeNode(ForeignScanState);
 	scanstate->ss.ps.plan = (Plan *) node;
 	scanstate->ss.ps.state = estate;
+	scanstate->ss.ps.ExecProcNode = ExecForeignScan;
 
 	/*
 	 * Miscellaneous initialization
diff --git a/src/backend/executor/nodeFunctionscan.c b/src/backend/executor/nodeFunctionscan.c
index 3217d641d76..9f87a7e5cdd 100644
--- a/src/backend/executor/nodeFunctionscan.c
+++ b/src/backend/executor/nodeFunctionscan.c
@@ -262,9 +262,11 @@ FunctionRecheck(FunctionScanState *node, TupleTableSlot *slot)
  *		access method functions.
  * ----------------------------------------------------------------
  */
-TupleTableSlot *
-ExecFunctionScan(FunctionScanState *node)
+static TupleTableSlot *
+ExecFunctionScan(PlanState *pstate)
 {
+	FunctionScanState *node = castNode(FunctionScanState, pstate);
+
 	return ExecScan(&node->ss,
 					(ExecScanAccessMtd) FunctionNext,
 					(ExecScanRecheckMtd) FunctionRecheck);
@@ -299,6 +301,7 @@ ExecInitFunctionScan(FunctionScan *node, EState *estate, int eflags)
 	scanstate = makeNode(FunctionScanState);
 	scanstate->ss.ps.plan = (Plan *) node;
 	scanstate->ss.ps.state = estate;
+	scanstate->ss.ps.ExecProcNode = ExecFunctionScan;
 	scanstate->eflags = eflags;
 
 	/*
diff --git a/src/backend/executor/nodeGather.c b/src/backend/executor/nodeGather.c
index 5dbe19c056d..e8d94ee6f38 100644
--- a/src/backend/executor/nodeGather.c
+++ b/src/backend/executor/nodeGather.c
@@ -43,6 +43,7 @@
 #include "utils/rel.h"
 
 
+static TupleTableSlot *ExecGather(PlanState *pstate);
 static TupleTableSlot *gather_getnext(GatherState *gatherstate);
 static HeapTuple gather_readnext(GatherState *gatherstate);
 static void ExecShutdownGatherWorkers(GatherState *node);
@@ -69,6 +70,7 @@ ExecInitGather(Gather *node, EState *estate, int eflags)
 	gatherstate = makeNode(GatherState);
 	gatherstate->ps.plan = (Plan *) node;
 	gatherstate->ps.state = estate;
+	gatherstate->ps.ExecProcNode = ExecGather;
 	gatherstate->need_to_scan_locally = !node->single_copy;
 
 	/*
@@ -120,9 +122,10 @@ ExecInitGather(Gather *node, EState *estate, int eflags)
  *		the next qualifying tuple.
  * ----------------------------------------------------------------
  */
-TupleTableSlot *
-ExecGather(GatherState *node)
+static TupleTableSlot *
+ExecGather(PlanState *pstate)
 {
+	GatherState *node = castNode(GatherState, pstate);
 	TupleTableSlot *fslot = node->funnel_slot;
 	int			i;
 	TupleTableSlot *slot;
diff --git a/src/backend/executor/nodeGatherMerge.c b/src/backend/executor/nodeGatherMerge.c
index 0aff3798f75..9a81e225100 100644
--- a/src/backend/executor/nodeGatherMerge.c
+++ b/src/backend/executor/nodeGatherMerge.c
@@ -44,6 +44,7 @@ typedef struct GMReaderTupleBuffer
  */
 #define MAX_TUPLE_STORE 10
 
+static TupleTableSlot *ExecGatherMerge(PlanState *pstate);
 static int32 heap_compare_slots(Datum a, Datum b, void *arg);
 static TupleTableSlot *gather_merge_getnext(GatherMergeState *gm_state);
 static HeapTuple gm_readnext_tuple(GatherMergeState *gm_state, int nreader,
@@ -75,6 +76,7 @@ ExecInitGatherMerge(GatherMerge *node, EState *estate, int eflags)
 	gm_state = makeNode(GatherMergeState);
 	gm_state->ps.plan = (Plan *) node;
 	gm_state->ps.state = estate;
+	gm_state->ps.ExecProcNode = ExecGatherMerge;
 
 	/*
 	 * Miscellaneous initialization
@@ -157,9 +159,10 @@ ExecInitGatherMerge(GatherMerge *node, EState *estate, int eflags)
  *		the next qualifying tuple.
  * ----------------------------------------------------------------
  */
-TupleTableSlot *
-ExecGatherMerge(GatherMergeState *node)
+static TupleTableSlot *
+ExecGatherMerge(PlanState *pstate)
 {
+	GatherMergeState *node = castNode(GatherMergeState, pstate);
 	TupleTableSlot *slot;
 	ExprContext *econtext;
 	int			i;
diff --git a/src/backend/executor/nodeGroup.c b/src/backend/executor/nodeGroup.c
index fc5e0e59bcc..ab4ae24a6bc 100644
--- a/src/backend/executor/nodeGroup.c
+++ b/src/backend/executor/nodeGroup.c
@@ -32,9 +32,10 @@
  *
  *		Return one tuple for each group of matching input tuples.
  */
-TupleTableSlot *
-ExecGroup(GroupState *node)
+static TupleTableSlot *
+ExecGroup(PlanState *pstate)
 {
+	GroupState *node = castNode(GroupState, pstate);
 	ExprContext *econtext;
 	int			numCols;
 	AttrNumber *grpColIdx;
@@ -175,6 +176,7 @@ ExecInitGroup(Group *node, EState *estate, int eflags)
 	grpstate = makeNode(GroupState);
 	grpstate->ss.ps.plan = (Plan *) node;
 	grpstate->ss.ps.state = estate;
+	grpstate->ss.ps.ExecProcNode = ExecGroup;
 	grpstate->grp_done = FALSE;
 
 	/*
diff --git a/src/backend/executor/nodeHash.c b/src/backend/executor/nodeHash.c
index fbeb562489c..d10d94ccc26 100644
--- a/src/backend/executor/nodeHash.c
+++ b/src/backend/executor/nodeHash.c
@@ -56,8 +56,8 @@ static void *dense_alloc(HashJoinTable hashtable, Size size);
  *		stub for pro forma compliance
  * ----------------------------------------------------------------
  */
-TupleTableSlot *
-ExecHash(HashState *node)
+static TupleTableSlot *
+ExecHash(PlanState *pstate)
 {
 	elog(ERROR, "Hash node does not support ExecProcNode call convention");
 	return NULL;
@@ -172,6 +172,7 @@ ExecInitHash(Hash *node, EState *estate, int eflags)
 	hashstate = makeNode(HashState);
 	hashstate->ps.plan = (Plan *) node;
 	hashstate->ps.state = estate;
+	hashstate->ps.ExecProcNode = ExecHash;
 	hashstate->hashtable = NULL;
 	hashstate->hashkeys = NIL;	/* will be set by parent HashJoin */
 
diff --git a/src/backend/executor/nodeHashjoin.c b/src/backend/executor/nodeHashjoin.c
index 252960c81c5..ab1632cc13d 100644
--- a/src/backend/executor/nodeHashjoin.c
+++ b/src/backend/executor/nodeHashjoin.c
@@ -58,9 +58,10 @@ static bool ExecHashJoinNewBatch(HashJoinState *hjstate);
  *			  the other one is "outer".
  * ----------------------------------------------------------------
  */
-TupleTableSlot *				/* return: a tuple or NULL */
-ExecHashJoin(HashJoinState *node)
+static TupleTableSlot *			/* return: a tuple or NULL */
+ExecHashJoin(PlanState *pstate)
 {
+	HashJoinState *node = castNode(HashJoinState, pstate);
 	PlanState  *outerNode;
 	HashState  *hashNode;
 	ExprState  *joinqual;
@@ -399,6 +400,7 @@ ExecInitHashJoin(HashJoin *node, EState *estate, int eflags)
 	hjstate = makeNode(HashJoinState);
 	hjstate->js.ps.plan = (Plan *) node;
 	hjstate->js.ps.state = estate;
+	hjstate->js.ps.ExecProcNode = ExecHashJoin;
 
 	/*
 	 * Miscellaneous initialization
diff --git a/src/backend/executor/nodeIndexonlyscan.c b/src/backend/executor/nodeIndexonlyscan.c
index e2000764a46..fe7ba3f1a4f 100644
--- a/src/backend/executor/nodeIndexonlyscan.c
+++ b/src/backend/executor/nodeIndexonlyscan.c
@@ -306,9 +306,11 @@ IndexOnlyRecheck(IndexOnlyScanState *node, TupleTableSlot *slot)
  *		ExecIndexOnlyScan(node)
  * ----------------------------------------------------------------
  */
-TupleTableSlot *
-ExecIndexOnlyScan(IndexOnlyScanState *node)
+static TupleTableSlot *
+ExecIndexOnlyScan(PlanState *pstate)
 {
+	IndexOnlyScanState *node = castNode(IndexOnlyScanState, pstate);
+
 	/*
 	 * If we have runtime keys and they've not already been set up, do it now.
 	 */
@@ -476,6 +478,7 @@ ExecInitIndexOnlyScan(IndexOnlyScan *node, EState *estate, int eflags)
 	indexstate = makeNode(IndexOnlyScanState);
 	indexstate->ss.ps.plan = (Plan *) node;
 	indexstate->ss.ps.state = estate;
+	indexstate->ss.ps.ExecProcNode = ExecIndexOnlyScan;
 	indexstate->ioss_HeapFetches = 0;
 
 	/*
diff --git a/src/backend/executor/nodeIndexscan.c b/src/backend/executor/nodeIndexscan.c
index 6704ede9955..404076d5930 100644
--- a/src/backend/executor/nodeIndexscan.c
+++ b/src/backend/executor/nodeIndexscan.c
@@ -542,9 +542,11 @@ reorderqueue_pop(IndexScanState *node)
  *		ExecIndexScan(node)
  * ----------------------------------------------------------------
  */
-TupleTableSlot *
-ExecIndexScan(IndexScanState *node)
+static TupleTableSlot *
+ExecIndexScan(PlanState *pstate)
 {
+	IndexScanState *node = castNode(IndexScanState, pstate);
+
 	/*
 	 * If we have runtime keys and they've not already been set up, do it now.
 	 */
@@ -910,6 +912,7 @@ ExecInitIndexScan(IndexScan *node, EState *estate, int eflags)
 	indexstate = makeNode(IndexScanState);
 	indexstate->ss.ps.plan = (Plan *) node;
 	indexstate->ss.ps.state = estate;
+	indexstate->ss.ps.ExecProcNode = ExecIndexScan;
 
 	/*
 	 * Miscellaneous initialization
diff --git a/src/backend/executor/nodeLimit.c b/src/backend/executor/nodeLimit.c
index 2ed3523257f..ac5a2ff0e60 100644
--- a/src/backend/executor/nodeLimit.c
+++ b/src/backend/executor/nodeLimit.c
@@ -37,9 +37,10 @@ static void pass_down_bound(LimitState *node, PlanState *child_node);
  *		filtering on the stream of tuples returned by a subplan.
  * ----------------------------------------------------------------
  */
-TupleTableSlot *				/* return: a tuple or NULL */
-ExecLimit(LimitState *node)
+static TupleTableSlot *			/* return: a tuple or NULL */
+ExecLimit(PlanState *pstate)
 {
+	LimitState *node = castNode(LimitState, pstate);
 	ScanDirection direction;
 	TupleTableSlot *slot;
 	PlanState  *outerPlan;
@@ -378,6 +379,7 @@ ExecInitLimit(Limit *node, EState *estate, int eflags)
 	limitstate = makeNode(LimitState);
 	limitstate->ps.plan = (Plan *) node;
 	limitstate->ps.state = estate;
+	limitstate->ps.ExecProcNode = ExecLimit;
 
 	limitstate->lstate = LIMIT_INITIAL;
 
diff --git a/src/backend/executor/nodeLockRows.c b/src/backend/executor/nodeLockRows.c
index dd4e2c5f2f1..93895600a5d 100644
--- a/src/backend/executor/nodeLockRows.c
+++ b/src/backend/executor/nodeLockRows.c
@@ -36,9 +36,10 @@
  *		ExecLockRows
  * ----------------------------------------------------------------
  */
-TupleTableSlot *				/* return: a tuple or NULL */
-ExecLockRows(LockRowsState *node)
+static TupleTableSlot *			/* return: a tuple or NULL */
+ExecLockRows(PlanState *pstate)
 {
+	LockRowsState *node = castNode(LockRowsState, pstate);
 	TupleTableSlot *slot;
 	EState	   *estate;
 	PlanState  *outerPlan;
@@ -364,6 +365,7 @@ ExecInitLockRows(LockRows *node, EState *estate, int eflags)
 	lrstate = makeNode(LockRowsState);
 	lrstate->ps.plan = (Plan *) node;
 	lrstate->ps.state = estate;
+	lrstate->ps.ExecProcNode = ExecLockRows;
 
 	/*
 	 * Miscellaneous initialization
diff --git a/src/backend/executor/nodeMaterial.c b/src/backend/executor/nodeMaterial.c
index 33429495909..91178f10198 100644
--- a/src/backend/executor/nodeMaterial.c
+++ b/src/backend/executor/nodeMaterial.c
@@ -35,9 +35,10 @@
  *
  * ----------------------------------------------------------------
  */
-TupleTableSlot *				/* result tuple from subplan */
-ExecMaterial(MaterialState *node)
+static TupleTableSlot *			/* result tuple from subplan */
+ExecMaterial(PlanState *pstate)
 {
+	MaterialState *node = castNode(MaterialState, pstate);
 	EState	   *estate;
 	ScanDirection dir;
 	bool		forward;
@@ -173,6 +174,7 @@ ExecInitMaterial(Material *node, EState *estate, int eflags)
 	matstate = makeNode(MaterialState);
 	matstate->ss.ps.plan = (Plan *) node;
 	matstate->ss.ps.state = estate;
+	matstate->ss.ps.ExecProcNode = ExecMaterial;
 
 	/*
 	 * We must have a tuplestore buffering the subplan output to do backward
diff --git a/src/backend/executor/nodeMergeAppend.c b/src/backend/executor/nodeMergeAppend.c
index d41def13506..6bf490bd700 100644
--- a/src/backend/executor/nodeMergeAppend.c
+++ b/src/backend/executor/nodeMergeAppend.c
@@ -50,6 +50,7 @@
  */
 typedef int32 SlotNumber;
 
+static TupleTableSlot *ExecMergeAppend(PlanState *pstate);
 static int	heap_compare_slots(Datum a, Datum b, void *arg);
 
 
@@ -89,6 +90,7 @@ ExecInitMergeAppend(MergeAppend *node, EState *estate, int eflags)
 	 */
 	mergestate->ps.plan = (Plan *) node;
 	mergestate->ps.state = estate;
+	mergestate->ps.ExecProcNode = ExecMergeAppend;
 	mergestate->mergeplans = mergeplanstates;
 	mergestate->ms_nplans = nplans;
 
@@ -169,9 +171,10 @@ ExecInitMergeAppend(MergeAppend *node, EState *estate, int eflags)
  *		Handles iteration over multiple subplans.
  * ----------------------------------------------------------------
  */
-TupleTableSlot *
-ExecMergeAppend(MergeAppendState *node)
+static TupleTableSlot *
+ExecMergeAppend(PlanState *pstate)
 {
+	MergeAppendState *node = castNode(MergeAppendState, pstate);
 	TupleTableSlot *result;
 	SlotNumber	i;
 
diff --git a/src/backend/executor/nodeMergejoin.c b/src/backend/executor/nodeMergejoin.c
index 324b61b8c0c..925b4cf5535 100644
--- a/src/backend/executor/nodeMergejoin.c
+++ b/src/backend/executor/nodeMergejoin.c
@@ -596,9 +596,10 @@ ExecMergeTupleDump(MergeJoinState *mergestate)
  *		ExecMergeJoin
  * ----------------------------------------------------------------
  */
-TupleTableSlot *
-ExecMergeJoin(MergeJoinState *node)
+static TupleTableSlot *
+ExecMergeJoin(PlanState *pstate)
 {
+	MergeJoinState *node = castNode(MergeJoinState, pstate);
 	ExprState  *joinqual;
 	ExprState  *otherqual;
 	bool		qualResult;
@@ -1448,6 +1449,7 @@ ExecInitMergeJoin(MergeJoin *node, EState *estate, int eflags)
 	mergestate = makeNode(MergeJoinState);
 	mergestate->js.ps.plan = (Plan *) node;
 	mergestate->js.ps.state = estate;
+	mergestate->js.ps.ExecProcNode = ExecMergeJoin;
 
 	/*
 	 * Miscellaneous initialization
diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c
index 637a582e1cc..0dde0ed6eb2 100644
--- a/src/backend/executor/nodeModifyTable.c
+++ b/src/backend/executor/nodeModifyTable.c
@@ -1535,9 +1535,10 @@ ExecSetupTransitionCaptureState(ModifyTableState *mtstate, EState *estate)
  *		if needed.
  * ----------------------------------------------------------------
  */
-TupleTableSlot *
-ExecModifyTable(ModifyTableState *node)
+static TupleTableSlot *
+ExecModifyTable(PlanState *pstate)
 {
+	ModifyTableState *node = castNode(ModifyTableState, pstate);
 	EState	   *estate = node->ps.state;
 	CmdType		operation = node->operation;
 	ResultRelInfo *saved_resultRelInfo;
@@ -1806,6 +1807,7 @@ ExecInitModifyTable(ModifyTable *node, EState *estate, int eflags)
 	mtstate = makeNode(ModifyTableState);
 	mtstate->ps.plan = (Plan *) node;
 	mtstate->ps.state = estate;
+	mtstate->ps.ExecProcNode = ExecModifyTable;
 
 	mtstate->operation = operation;
 	mtstate->canSetTag = node->canSetTag;
diff --git a/src/backend/executor/nodeNamedtuplestorescan.c b/src/backend/executor/nodeNamedtuplestorescan.c
index 62234869abb..3a65b9f5dc9 100644
--- a/src/backend/executor/nodeNamedtuplestorescan.c
+++ b/src/backend/executor/nodeNamedtuplestorescan.c
@@ -63,9 +63,11 @@ NamedTuplestoreScanRecheck(NamedTuplestoreScanState *node, TupleTableSlot *slot)
  *		access method functions.
  * ----------------------------------------------------------------
  */
-TupleTableSlot *
-ExecNamedTuplestoreScan(NamedTuplestoreScanState *node)
+static TupleTableSlot *
+ExecNamedTuplestoreScan(PlanState *pstate)
 {
+	NamedTuplestoreScanState *node = castNode(NamedTuplestoreScanState, pstate);
+
 	return ExecScan(&node->ss,
 					(ExecScanAccessMtd) NamedTuplestoreScanNext,
 					(ExecScanRecheckMtd) NamedTuplestoreScanRecheck);
@@ -97,6 +99,7 @@ ExecInitNamedTuplestoreScan(NamedTuplestoreScan *node, EState *estate, int eflag
 	scanstate = makeNode(NamedTuplestoreScanState);
 	scanstate->ss.ps.plan = (Plan *) node;
 	scanstate->ss.ps.state = estate;
+	scanstate->ss.ps.ExecProcNode = ExecNamedTuplestoreScan;
 
 	enr = get_ENR(estate->es_queryEnv, node->enrname);
 	if (!enr)
diff --git a/src/backend/executor/nodeNestloop.c b/src/backend/executor/nodeNestloop.c
index bedc374ef05..4447b7c051a 100644
--- a/src/backend/executor/nodeNestloop.c
+++ b/src/backend/executor/nodeNestloop.c
@@ -57,9 +57,10 @@
  *			   are prepared to return the first tuple.
  * ----------------------------------------------------------------
  */
-TupleTableSlot *
-ExecNestLoop(NestLoopState *node)
+static TupleTableSlot *
+ExecNestLoop(PlanState *pstate)
 {
+	NestLoopState *node = castNode(NestLoopState, pstate);
 	NestLoop   *nl;
 	PlanState  *innerPlan;
 	PlanState  *outerPlan;
@@ -275,6 +276,7 @@ ExecInitNestLoop(NestLoop *node, EState *estate, int eflags)
 	nlstate = makeNode(NestLoopState);
 	nlstate->js.ps.plan = (Plan *) node;
 	nlstate->js.ps.state = estate;
+	nlstate->js.ps.ExecProcNode = ExecNestLoop;
 
 	/*
 	 * Miscellaneous initialization
diff --git a/src/backend/executor/nodeProjectSet.c b/src/backend/executor/nodeProjectSet.c
index 3b69c7adeea..d93462c5421 100644
--- a/src/backend/executor/nodeProjectSet.c
+++ b/src/backend/executor/nodeProjectSet.c
@@ -39,9 +39,10 @@ static TupleTableSlot *ExecProjectSRF(ProjectSetState *node, bool continuing);
  *		returning functions).
  * ----------------------------------------------------------------
  */
-TupleTableSlot *
-ExecProjectSet(ProjectSetState *node)
+static TupleTableSlot *
+ExecProjectSet(PlanState *pstate)
 {
+	ProjectSetState *node = castNode(ProjectSetState, pstate);
 	TupleTableSlot *outerTupleSlot;
 	TupleTableSlot *resultSlot;
 	PlanState  *outerPlan;
@@ -215,6 +216,7 @@ ExecInitProjectSet(ProjectSet *node, EState *estate, int eflags)
 	state = makeNode(ProjectSetState);
 	state->ps.plan = (Plan *) node;
 	state->ps.state = estate;
+	state->ps.ExecProcNode = ExecProjectSet;
 
 	state->pending_srf_tuples = false;
 
diff --git a/src/backend/executor/nodeRecursiveunion.c b/src/backend/executor/nodeRecursiveunion.c
index 2802fffa2b6..a64dd1397a4 100644
--- a/src/backend/executor/nodeRecursiveunion.c
+++ b/src/backend/executor/nodeRecursiveunion.c
@@ -66,9 +66,10 @@ build_hash_table(RecursiveUnionState *rustate)
  * 2.6 go back to 2.2
  * ----------------------------------------------------------------
  */
-TupleTableSlot *
-ExecRecursiveUnion(RecursiveUnionState *node)
+static TupleTableSlot *
+ExecRecursiveUnion(PlanState *pstate)
 {
+	RecursiveUnionState *node = castNode(RecursiveUnionState, pstate);
 	PlanState  *outerPlan = outerPlanState(node);
 	PlanState  *innerPlan = innerPlanState(node);
 	RecursiveUnion *plan = (RecursiveUnion *) node->ps.plan;
@@ -172,6 +173,7 @@ ExecInitRecursiveUnion(RecursiveUnion *node, EState *estate, int eflags)
 	rustate = makeNode(RecursiveUnionState);
 	rustate->ps.plan = (Plan *) node;
 	rustate->ps.state = estate;
+	rustate->ps.ExecProcNode = ExecRecursiveUnion;
 
 	rustate->eqfunctions = NULL;
 	rustate->hashfunctions = NULL;
diff --git a/src/backend/executor/nodeResult.c b/src/backend/executor/nodeResult.c
index f007f46784f..4c879d87655 100644
--- a/src/backend/executor/nodeResult.c
+++ b/src/backend/executor/nodeResult.c
@@ -64,9 +64,10 @@
  *		'nil' if the constant qualification is not satisfied.
  * ----------------------------------------------------------------
  */
-TupleTableSlot *
-ExecResult(ResultState *node)
+static TupleTableSlot *
+ExecResult(PlanState *pstate)
 {
+	ResultState *node = castNode(ResultState, pstate);
 	TupleTableSlot *outerTupleSlot;
 	PlanState  *outerPlan;
 	ExprContext *econtext;
@@ -191,6 +192,7 @@ ExecInitResult(Result *node, EState *estate, int eflags)
 	resstate = makeNode(ResultState);
 	resstate->ps.plan = (Plan *) node;
 	resstate->ps.state = estate;
+	resstate->ps.ExecProcNode = ExecResult;
 
 	resstate->rs_done = false;
 	resstate->rs_checkqual = (node->resconstantqual == NULL) ? false : true;
diff --git a/src/backend/executor/nodeSamplescan.c b/src/backend/executor/nodeSamplescan.c
index b710ef7edf2..9c74a836e40 100644
--- a/src/backend/executor/nodeSamplescan.c
+++ b/src/backend/executor/nodeSamplescan.c
@@ -96,10 +96,12 @@ SampleRecheck(SampleScanState *node, TupleTableSlot *slot)
  *		access method functions.
  * ----------------------------------------------------------------
  */
-TupleTableSlot *
-ExecSampleScan(SampleScanState *node)
+static TupleTableSlot *
+ExecSampleScan(PlanState *pstate)
 {
-	return ExecScan((ScanState *) node,
+	SampleScanState *node = castNode(SampleScanState, pstate);
+
+	return ExecScan(&node->ss,
 					(ExecScanAccessMtd) SampleNext,
 					(ExecScanRecheckMtd) SampleRecheck);
 }
@@ -153,6 +155,7 @@ ExecInitSampleScan(SampleScan *node, EState *estate, int eflags)
 	scanstate = makeNode(SampleScanState);
 	scanstate->ss.ps.plan = (Plan *) node;
 	scanstate->ss.ps.state = estate;
+	scanstate->ss.ps.ExecProcNode = ExecSampleScan;
 
 	/*
 	 * Miscellaneous initialization
diff --git a/src/backend/executor/nodeSeqscan.c b/src/backend/executor/nodeSeqscan.c
index 307df87c82f..5c49d4ca8a9 100644
--- a/src/backend/executor/nodeSeqscan.c
+++ b/src/backend/executor/nodeSeqscan.c
@@ -121,10 +121,12 @@ SeqRecheck(SeqScanState *node, TupleTableSlot *slot)
  *		access method functions.
  * ----------------------------------------------------------------
  */
-TupleTableSlot *
-ExecSeqScan(SeqScanState *node)
+static TupleTableSlot *
+ExecSeqScan(PlanState *pstate)
 {
-	return ExecScan((ScanState *) node,
+	SeqScanState *node = castNode(SeqScanState, pstate);
+
+	return ExecScan(&node->ss,
 					(ExecScanAccessMtd) SeqNext,
 					(ExecScanRecheckMtd) SeqRecheck);
 }
@@ -177,6 +179,7 @@ ExecInitSeqScan(SeqScan *node, EState *estate, int eflags)
 	scanstate = makeNode(SeqScanState);
 	scanstate->ss.ps.plan = (Plan *) node;
 	scanstate->ss.ps.state = estate;
+	scanstate->ss.ps.ExecProcNode = ExecSeqScan;
 
 	/*
 	 * Miscellaneous initialization
diff --git a/src/backend/executor/nodeSetOp.c b/src/backend/executor/nodeSetOp.c
index 56c5643f175..571cbf86b1d 100644
--- a/src/backend/executor/nodeSetOp.c
+++ b/src/backend/executor/nodeSetOp.c
@@ -180,9 +180,10 @@ set_output_count(SetOpState *setopstate, SetOpStatePerGroup pergroup)
  *		ExecSetOp
  * ----------------------------------------------------------------
  */
-TupleTableSlot *				/* return: a tuple or NULL */
-ExecSetOp(SetOpState *node)
+static TupleTableSlot *			/* return: a tuple or NULL */
+ExecSetOp(PlanState *pstate)
 {
+	SetOpState *node = castNode(SetOpState, pstate);
 	SetOp	   *plannode = (SetOp *) node->ps.plan;
 	TupleTableSlot *resultTupleSlot = node->ps.ps_ResultTupleSlot;
 
@@ -485,6 +486,7 @@ ExecInitSetOp(SetOp *node, EState *estate, int eflags)
 	setopstate = makeNode(SetOpState);
 	setopstate->ps.plan = (Plan *) node;
 	setopstate->ps.state = estate;
+	setopstate->ps.ExecProcNode = ExecSetOp;
 
 	setopstate->eqfunctions = NULL;
 	setopstate->hashfunctions = NULL;
diff --git a/src/backend/executor/nodeSort.c b/src/backend/executor/nodeSort.c
index 799a4e92042..aae4150e2c8 100644
--- a/src/backend/executor/nodeSort.c
+++ b/src/backend/executor/nodeSort.c
@@ -35,9 +35,10 @@
  *		  -- the outer child is prepared to return the first tuple.
  * ----------------------------------------------------------------
  */
-TupleTableSlot *
-ExecSort(SortState *node)
+static TupleTableSlot *
+ExecSort(PlanState *pstate)
 {
+	SortState  *node = castNode(SortState, pstate);
 	EState	   *estate;
 	ScanDirection dir;
 	Tuplesortstate *tuplesortstate;
@@ -165,6 +166,7 @@ ExecInitSort(Sort *node, EState *estate, int eflags)
 	sortstate = makeNode(SortState);
 	sortstate->ss.ps.plan = (Plan *) node;
 	sortstate->ss.ps.state = estate;
+	sortstate->ss.ps.ExecProcNode = ExecSort;
 
 	/*
 	 * We must have random access to the sort output to do backward scan or
diff --git a/src/backend/executor/nodeSubqueryscan.c b/src/backend/executor/nodeSubqueryscan.c
index ae184700a67..088c92992ec 100644
--- a/src/backend/executor/nodeSubqueryscan.c
+++ b/src/backend/executor/nodeSubqueryscan.c
@@ -79,9 +79,11 @@ SubqueryRecheck(SubqueryScanState *node, TupleTableSlot *slot)
  *		access method functions.
  * ----------------------------------------------------------------
  */
-TupleTableSlot *
-ExecSubqueryScan(SubqueryScanState *node)
+static TupleTableSlot *
+ExecSubqueryScan(PlanState *pstate)
 {
+	SubqueryScanState *node = castNode(SubqueryScanState, pstate);
+
 	return ExecScan(&node->ss,
 					(ExecScanAccessMtd) SubqueryNext,
 					(ExecScanRecheckMtd) SubqueryRecheck);
@@ -109,6 +111,7 @@ ExecInitSubqueryScan(SubqueryScan *node, EState *estate, int eflags)
 	subquerystate = makeNode(SubqueryScanState);
 	subquerystate->ss.ps.plan = (Plan *) node;
 	subquerystate->ss.ps.state = estate;
+	subquerystate->ss.ps.ExecProcNode = ExecSubqueryScan;
 
 	/*
 	 * Miscellaneous initialization
diff --git a/src/backend/executor/nodeTableFuncscan.c b/src/backend/executor/nodeTableFuncscan.c
index 2859363fe2c..b03d2ef7622 100644
--- a/src/backend/executor/nodeTableFuncscan.c
+++ b/src/backend/executor/nodeTableFuncscan.c
@@ -93,9 +93,11 @@ TableFuncRecheck(TableFuncScanState *node, TupleTableSlot *slot)
  *		access method functions.
  * ----------------------------------------------------------------
  */
-TupleTableSlot *
-ExecTableFuncScan(TableFuncScanState *node)
+static TupleTableSlot *
+ExecTableFuncScan(PlanState *pstate)
 {
+	TableFuncScanState *node = castNode(TableFuncScanState, pstate);
+
 	return ExecScan(&node->ss,
 					(ExecScanAccessMtd) TableFuncNext,
 					(ExecScanRecheckMtd) TableFuncRecheck);
@@ -128,6 +130,7 @@ ExecInitTableFuncScan(TableFuncScan *node, EState *estate, int eflags)
 	scanstate = makeNode(TableFuncScanState);
 	scanstate->ss.ps.plan = (Plan *) node;
 	scanstate->ss.ps.state = estate;
+	scanstate->ss.ps.ExecProcNode = ExecTableFuncScan;
 
 	/*
 	 * Miscellaneous initialization
diff --git a/src/backend/executor/nodeTidscan.c b/src/backend/executor/nodeTidscan.c
index c122473bdf8..0ee76e7d252 100644
--- a/src/backend/executor/nodeTidscan.c
+++ b/src/backend/executor/nodeTidscan.c
@@ -445,9 +445,11 @@ TidRecheck(TidScanState *node, TupleTableSlot *slot)
  *		  -- tidPtr is -1.
  * ----------------------------------------------------------------
  */
-TupleTableSlot *
-ExecTidScan(TidScanState *node)
+static TupleTableSlot *
+ExecTidScan(PlanState *pstate)
 {
+	TidScanState *node = castNode(TidScanState, pstate);
+
 	return ExecScan(&node->ss,
 					(ExecScanAccessMtd) TidNext,
 					(ExecScanRecheckMtd) TidRecheck);
@@ -519,6 +521,7 @@ ExecInitTidScan(TidScan *node, EState *estate, int eflags)
 	tidstate = makeNode(TidScanState);
 	tidstate->ss.ps.plan = (Plan *) node;
 	tidstate->ss.ps.state = estate;
+	tidstate->ss.ps.ExecProcNode = ExecTidScan;
 
 	/*
 	 * Miscellaneous initialization
diff --git a/src/backend/executor/nodeUnique.c b/src/backend/executor/nodeUnique.c
index db78c88368b..621fdd9b9c1 100644
--- a/src/backend/executor/nodeUnique.c
+++ b/src/backend/executor/nodeUnique.c
@@ -43,9 +43,10 @@
  *		ExecUnique
  * ----------------------------------------------------------------
  */
-TupleTableSlot *				/* return: a tuple or NULL */
-ExecUnique(UniqueState *node)
+static TupleTableSlot *			/* return: a tuple or NULL */
+ExecUnique(PlanState *pstate)
 {
+	UniqueState *node = castNode(UniqueState, pstate);
 	Unique	   *plannode = (Unique *) node->ps.plan;
 	TupleTableSlot *resultTupleSlot;
 	TupleTableSlot *slot;
@@ -125,6 +126,7 @@ ExecInitUnique(Unique *node, EState *estate, int eflags)
 	uniquestate = makeNode(UniqueState);
 	uniquestate->ps.plan = (Plan *) node;
 	uniquestate->ps.state = estate;
+	uniquestate->ps.ExecProcNode = ExecUnique;
 
 	/*
 	 * Miscellaneous initialization
diff --git a/src/backend/executor/nodeValuesscan.c b/src/backend/executor/nodeValuesscan.c
index 9ee776c4c32..6eacaed8bb8 100644
--- a/src/backend/executor/nodeValuesscan.c
+++ b/src/backend/executor/nodeValuesscan.c
@@ -185,9 +185,11 @@ ValuesRecheck(ValuesScanState *node, TupleTableSlot *slot)
  *		access method functions.
  * ----------------------------------------------------------------
  */
-TupleTableSlot *
-ExecValuesScan(ValuesScanState *node)
+static TupleTableSlot *
+ExecValuesScan(PlanState *pstate)
 {
+	ValuesScanState *node = castNode(ValuesScanState, pstate);
+
 	return ExecScan(&node->ss,
 					(ExecScanAccessMtd) ValuesNext,
 					(ExecScanRecheckMtd) ValuesRecheck);
@@ -218,6 +220,7 @@ ExecInitValuesScan(ValuesScan *node, EState *estate, int eflags)
 	scanstate = makeNode(ValuesScanState);
 	scanstate->ss.ps.plan = (Plan *) node;
 	scanstate->ss.ps.state = estate;
+	scanstate->ss.ps.ExecProcNode = ExecValuesScan;
 
 	/*
 	 * Miscellaneous initialization
diff --git a/src/backend/executor/nodeWindowAgg.c b/src/backend/executor/nodeWindowAgg.c
index 9da35ac506b..80be46029f4 100644
--- a/src/backend/executor/nodeWindowAgg.c
+++ b/src/backend/executor/nodeWindowAgg.c
@@ -1587,9 +1587,10 @@ update_frametailpos(WindowObject winobj, TupleTableSlot *slot)
  *	returned rows is exactly the same as its outer subplan's result.
  * -----------------
  */
-TupleTableSlot *
-ExecWindowAgg(WindowAggState *winstate)
+static TupleTableSlot *
+ExecWindowAgg(PlanState *pstate)
 {
+	WindowAggState *winstate = castNode(WindowAggState, pstate);
 	ExprContext *econtext;
 	int			i;
 	int			numfuncs;
@@ -1790,6 +1791,7 @@ ExecInitWindowAgg(WindowAgg *node, EState *estate, int eflags)
 	winstate = makeNode(WindowAggState);
 	winstate->ss.ps.plan = (Plan *) node;
 	winstate->ss.ps.state = estate;
+	winstate->ss.ps.ExecProcNode = ExecWindowAgg;
 
 	/*
 	 * Create expression contexts.  We need two, one for per-input-tuple
diff --git a/src/backend/executor/nodeWorktablescan.c b/src/backend/executor/nodeWorktablescan.c
index d7616be0652..d5ffadda3e8 100644
--- a/src/backend/executor/nodeWorktablescan.c
+++ b/src/backend/executor/nodeWorktablescan.c
@@ -77,9 +77,11 @@ WorkTableScanRecheck(WorkTableScanState *node, TupleTableSlot *slot)
  *		access method functions.
  * ----------------------------------------------------------------
  */
-TupleTableSlot *
-ExecWorkTableScan(WorkTableScanState *node)
+static TupleTableSlot *
+ExecWorkTableScan(PlanState *pstate)
 {
+	WorkTableScanState *node = castNode(WorkTableScanState, pstate);
+
 	/*
 	 * On the first call, find the ancestor RecursiveUnion's state via the
 	 * Param slot reserved for it.  (We can't do this during node init because
@@ -144,6 +146,7 @@ ExecInitWorkTableScan(WorkTableScan *node, EState *estate, int eflags)
 	scanstate = makeNode(WorkTableScanState);
 	scanstate->ss.ps.plan = (Plan *) node;
 	scanstate->ss.ps.state = estate;
+	scanstate->ss.ps.ExecProcNode = ExecWorkTableScan;
 	scanstate->rustate = NULL;	/* we'll set this later */
 
 	/*
diff --git a/src/include/executor/executor.h b/src/include/executor/executor.h
index 59c28b709e6..60326f9d037 100644
--- a/src/include/executor/executor.h
+++ b/src/include/executor/executor.h
@@ -225,14 +225,31 @@ extern void EvalPlanQualBegin(EPQState *epqstate, EState *parentestate);
 extern void EvalPlanQualEnd(EPQState *epqstate);
 
 /*
- * prototypes from functions in execProcnode.c
+ * functions in execProcnode.c
  */
 extern PlanState *ExecInitNode(Plan *node, EState *estate, int eflags);
-extern TupleTableSlot *ExecProcNode(PlanState *node);
 extern Node *MultiExecProcNode(PlanState *node);
 extern void ExecEndNode(PlanState *node);
 extern bool ExecShutdownNode(PlanState *node);
 
+
+/* ----------------------------------------------------------------
+ *		ExecProcNode
+ *
+ *		Execute the given node to return a(nother) tuple.
+ * ----------------------------------------------------------------
+ */
+#ifndef FRONTEND
+static inline TupleTableSlot *
+ExecProcNode(PlanState *node)
+{
+	if (node->chgParam != NULL) /* something changed? */
+		ExecReScan(node);		/* let ReScan handle this */
+
+	return node->ExecProcNode(node);
+}
+#endif
+
 /*
  * prototypes from functions in execExpr.c
  */
diff --git a/src/include/executor/nodeAgg.h b/src/include/executor/nodeAgg.h
index fa11ba93a6b..eff5af9c2a4 100644
--- a/src/include/executor/nodeAgg.h
+++ b/src/include/executor/nodeAgg.h
@@ -17,7 +17,6 @@
 #include "nodes/execnodes.h"
 
 extern AggState *ExecInitAgg(Agg *node, EState *estate, int eflags);
-extern TupleTableSlot *ExecAgg(AggState *node);
 extern void ExecEndAgg(AggState *node);
 extern void ExecReScanAgg(AggState *node);
 
diff --git a/src/include/executor/nodeAppend.h b/src/include/executor/nodeAppend.h
index ee0b6ad23dd..4e38a1380e2 100644
--- a/src/include/executor/nodeAppend.h
+++ b/src/include/executor/nodeAppend.h
@@ -17,7 +17,6 @@
 #include "nodes/execnodes.h"
 
 extern AppendState *ExecInitAppend(Append *node, EState *estate, int eflags);
-extern TupleTableSlot *ExecAppend(AppendState *node);
 extern void ExecEndAppend(AppendState *node);
 extern void ExecReScanAppend(AppendState *node);
 
diff --git a/src/include/executor/nodeBitmapHeapscan.h b/src/include/executor/nodeBitmapHeapscan.h
index f477d1c7720..c77694cf22f 100644
--- a/src/include/executor/nodeBitmapHeapscan.h
+++ b/src/include/executor/nodeBitmapHeapscan.h
@@ -18,7 +18,6 @@
 #include "access/parallel.h"
 
 extern BitmapHeapScanState *ExecInitBitmapHeapScan(BitmapHeapScan *node, EState *estate, int eflags);
-extern TupleTableSlot *ExecBitmapHeapScan(BitmapHeapScanState *node);
 extern void ExecEndBitmapHeapScan(BitmapHeapScanState *node);
 extern void ExecReScanBitmapHeapScan(BitmapHeapScanState *node);
 extern void ExecBitmapHeapEstimate(BitmapHeapScanState *node,
diff --git a/src/include/executor/nodeCtescan.h b/src/include/executor/nodeCtescan.h
index 397bdfdd1ce..d2fbcbd5868 100644
--- a/src/include/executor/nodeCtescan.h
+++ b/src/include/executor/nodeCtescan.h
@@ -17,7 +17,6 @@
 #include "nodes/execnodes.h"
 
 extern CteScanState *ExecInitCteScan(CteScan *node, EState *estate, int eflags);
-extern TupleTableSlot *ExecCteScan(CteScanState *node);
 extern void ExecEndCteScan(CteScanState *node);
 extern void ExecReScanCteScan(CteScanState *node);
 
diff --git a/src/include/executor/nodeCustom.h b/src/include/executor/nodeCustom.h
index e81bcf7f21c..a1cc63ae1f3 100644
--- a/src/include/executor/nodeCustom.h
+++ b/src/include/executor/nodeCustom.h
@@ -21,7 +21,6 @@
  */
 extern CustomScanState *ExecInitCustomScan(CustomScan *custom_scan,
 				   EState *estate, int eflags);
-extern TupleTableSlot *ExecCustomScan(CustomScanState *node);
 extern void ExecEndCustomScan(CustomScanState *node);
 
 extern void ExecReScanCustomScan(CustomScanState *node);
diff --git a/src/include/executor/nodeForeignscan.h b/src/include/executor/nodeForeignscan.h
index 3ff4ecd8c93..0b662597d8f 100644
--- a/src/include/executor/nodeForeignscan.h
+++ b/src/include/executor/nodeForeignscan.h
@@ -18,7 +18,6 @@
 #include "nodes/execnodes.h"
 
 extern ForeignScanState *ExecInitForeignScan(ForeignScan *node, EState *estate, int eflags);
-extern TupleTableSlot *ExecForeignScan(ForeignScanState *node);
 extern void ExecEndForeignScan(ForeignScanState *node);
 extern void ExecReScanForeignScan(ForeignScanState *node);
 
diff --git a/src/include/executor/nodeFunctionscan.h b/src/include/executor/nodeFunctionscan.h
index 5e830ebdeae..aaa9d8c3166 100644
--- a/src/include/executor/nodeFunctionscan.h
+++ b/src/include/executor/nodeFunctionscan.h
@@ -17,7 +17,6 @@
 #include "nodes/execnodes.h"
 
 extern FunctionScanState *ExecInitFunctionScan(FunctionScan *node, EState *estate, int eflags);
-extern TupleTableSlot *ExecFunctionScan(FunctionScanState *node);
 extern void ExecEndFunctionScan(FunctionScanState *node);
 extern void ExecReScanFunctionScan(FunctionScanState *node);
 
diff --git a/src/include/executor/nodeGather.h b/src/include/executor/nodeGather.h
index b0006934d4d..189bd70041f 100644
--- a/src/include/executor/nodeGather.h
+++ b/src/include/executor/nodeGather.h
@@ -17,7 +17,6 @@
 #include "nodes/execnodes.h"
 
 extern GatherState *ExecInitGather(Gather *node, EState *estate, int eflags);
-extern TupleTableSlot *ExecGather(GatherState *node);
 extern void ExecEndGather(GatherState *node);
 extern void ExecShutdownGather(GatherState *node);
 extern void ExecReScanGather(GatherState *node);
diff --git a/src/include/executor/nodeGatherMerge.h b/src/include/executor/nodeGatherMerge.h
index 14b31a086c3..0154d733129 100644
--- a/src/include/executor/nodeGatherMerge.h
+++ b/src/include/executor/nodeGatherMerge.h
@@ -19,7 +19,6 @@
 extern GatherMergeState *ExecInitGatherMerge(GatherMerge *node,
 					EState *estate,
 					int eflags);
-extern TupleTableSlot *ExecGatherMerge(GatherMergeState *node);
 extern void ExecEndGatherMerge(GatherMergeState *node);
 extern void ExecReScanGatherMerge(GatherMergeState *node);
 extern void ExecShutdownGatherMerge(GatherMergeState *node);
diff --git a/src/include/executor/nodeGroup.h b/src/include/executor/nodeGroup.h
index 7358b61707c..b0d7e312c98 100644
--- a/src/include/executor/nodeGroup.h
+++ b/src/include/executor/nodeGroup.h
@@ -17,7 +17,6 @@
 #include "nodes/execnodes.h"
 
 extern GroupState *ExecInitGroup(Group *node, EState *estate, int eflags);
-extern TupleTableSlot *ExecGroup(GroupState *node);
 extern void ExecEndGroup(GroupState *node);
 extern void ExecReScanGroup(GroupState *node);
 
diff --git a/src/include/executor/nodeHash.h b/src/include/executor/nodeHash.h
index 8052f27d0b1..3ae556fb6c5 100644
--- a/src/include/executor/nodeHash.h
+++ b/src/include/executor/nodeHash.h
@@ -17,7 +17,6 @@
 #include "nodes/execnodes.h"
 
 extern HashState *ExecInitHash(Hash *node, EState *estate, int eflags);
-extern TupleTableSlot *ExecHash(HashState *node);
 extern Node *MultiExecHash(HashState *node);
 extern void ExecEndHash(HashState *node);
 extern void ExecReScanHash(HashState *node);
diff --git a/src/include/executor/nodeHashjoin.h b/src/include/executor/nodeHashjoin.h
index 541c81edc71..7469bfbf60c 100644
--- a/src/include/executor/nodeHashjoin.h
+++ b/src/include/executor/nodeHashjoin.h
@@ -18,7 +18,6 @@
 #include "storage/buffile.h"
 
 extern HashJoinState *ExecInitHashJoin(HashJoin *node, EState *estate, int eflags);
-extern TupleTableSlot *ExecHashJoin(HashJoinState *node);
 extern void ExecEndHashJoin(HashJoinState *node);
 extern void ExecReScanHashJoin(HashJoinState *node);
 
diff --git a/src/include/executor/nodeIndexonlyscan.h b/src/include/executor/nodeIndexonlyscan.h
index cf227daae04..c8a709c26ed 100644
--- a/src/include/executor/nodeIndexonlyscan.h
+++ b/src/include/executor/nodeIndexonlyscan.h
@@ -18,7 +18,6 @@
 #include "access/parallel.h"
 
 extern IndexOnlyScanState *ExecInitIndexOnlyScan(IndexOnlyScan *node, EState *estate, int eflags);
-extern TupleTableSlot *ExecIndexOnlyScan(IndexOnlyScanState *node);
 extern void ExecEndIndexOnlyScan(IndexOnlyScanState *node);
 extern void ExecIndexOnlyMarkPos(IndexOnlyScanState *node);
 extern void ExecIndexOnlyRestrPos(IndexOnlyScanState *node);
diff --git a/src/include/executor/nodeIndexscan.h b/src/include/executor/nodeIndexscan.h
index 0118234eca7..1668e347eef 100644
--- a/src/include/executor/nodeIndexscan.h
+++ b/src/include/executor/nodeIndexscan.h
@@ -18,7 +18,6 @@
 #include "nodes/execnodes.h"
 
 extern IndexScanState *ExecInitIndexScan(IndexScan *node, EState *estate, int eflags);
-extern TupleTableSlot *ExecIndexScan(IndexScanState *node);
 extern void ExecEndIndexScan(IndexScanState *node);
 extern void ExecIndexMarkPos(IndexScanState *node);
 extern void ExecIndexRestrPos(IndexScanState *node);
diff --git a/src/include/executor/nodeLimit.h b/src/include/executor/nodeLimit.h
index 7bb20d99786..db65b5524cd 100644
--- a/src/include/executor/nodeLimit.h
+++ b/src/include/executor/nodeLimit.h
@@ -17,7 +17,6 @@
 #include "nodes/execnodes.h"
 
 extern LimitState *ExecInitLimit(Limit *node, EState *estate, int eflags);
-extern TupleTableSlot *ExecLimit(LimitState *node);
 extern void ExecEndLimit(LimitState *node);
 extern void ExecReScanLimit(LimitState *node);
 
diff --git a/src/include/executor/nodeLockRows.h b/src/include/executor/nodeLockRows.h
index 6b90756e4c0..c9d05b87f1a 100644
--- a/src/include/executor/nodeLockRows.h
+++ b/src/include/executor/nodeLockRows.h
@@ -17,7 +17,6 @@
 #include "nodes/execnodes.h"
 
 extern LockRowsState *ExecInitLockRows(LockRows *node, EState *estate, int eflags);
-extern TupleTableSlot *ExecLockRows(LockRowsState *node);
 extern void ExecEndLockRows(LockRowsState *node);
 extern void ExecReScanLockRows(LockRowsState *node);
 
diff --git a/src/include/executor/nodeMaterial.h b/src/include/executor/nodeMaterial.h
index f69abbca82b..4b3c2578c9c 100644
--- a/src/include/executor/nodeMaterial.h
+++ b/src/include/executor/nodeMaterial.h
@@ -17,7 +17,6 @@
 #include "nodes/execnodes.h"
 
 extern MaterialState *ExecInitMaterial(Material *node, EState *estate, int eflags);
-extern TupleTableSlot *ExecMaterial(MaterialState *node);
 extern void ExecEndMaterial(MaterialState *node);
 extern void ExecMaterialMarkPos(MaterialState *node);
 extern void ExecMaterialRestrPos(MaterialState *node);
diff --git a/src/include/executor/nodeMergeAppend.h b/src/include/executor/nodeMergeAppend.h
index 3cc6ef549b3..a0ccbae9651 100644
--- a/src/include/executor/nodeMergeAppend.h
+++ b/src/include/executor/nodeMergeAppend.h
@@ -17,7 +17,6 @@
 #include "nodes/execnodes.h"
 
 extern MergeAppendState *ExecInitMergeAppend(MergeAppend *node, EState *estate, int eflags);
-extern TupleTableSlot *ExecMergeAppend(MergeAppendState *node);
 extern void ExecEndMergeAppend(MergeAppendState *node);
 extern void ExecReScanMergeAppend(MergeAppendState *node);
 
diff --git a/src/include/executor/nodeMergejoin.h b/src/include/executor/nodeMergejoin.h
index 32df25ae8b3..d20e41505db 100644
--- a/src/include/executor/nodeMergejoin.h
+++ b/src/include/executor/nodeMergejoin.h
@@ -17,7 +17,6 @@
 #include "nodes/execnodes.h"
 
 extern MergeJoinState *ExecInitMergeJoin(MergeJoin *node, EState *estate, int eflags);
-extern TupleTableSlot *ExecMergeJoin(MergeJoinState *node);
 extern void ExecEndMergeJoin(MergeJoinState *node);
 extern void ExecReScanMergeJoin(MergeJoinState *node);
 
diff --git a/src/include/executor/nodeModifyTable.h b/src/include/executor/nodeModifyTable.h
index 5a406f236d4..a2e7af98de8 100644
--- a/src/include/executor/nodeModifyTable.h
+++ b/src/include/executor/nodeModifyTable.h
@@ -16,7 +16,6 @@
 #include "nodes/execnodes.h"
 
 extern ModifyTableState *ExecInitModifyTable(ModifyTable *node, EState *estate, int eflags);
-extern TupleTableSlot *ExecModifyTable(ModifyTableState *node);
 extern void ExecEndModifyTable(ModifyTableState *node);
 extern void ExecReScanModifyTable(ModifyTableState *node);
 
diff --git a/src/include/executor/nodeNamedtuplestorescan.h b/src/include/executor/nodeNamedtuplestorescan.h
index 7f72fbe98af..395d978f624 100644
--- a/src/include/executor/nodeNamedtuplestorescan.h
+++ b/src/include/executor/nodeNamedtuplestorescan.h
@@ -17,7 +17,6 @@
 #include "nodes/execnodes.h"
 
 extern NamedTuplestoreScanState *ExecInitNamedTuplestoreScan(NamedTuplestoreScan *node, EState *estate, int eflags);
-extern TupleTableSlot *ExecNamedTuplestoreScan(NamedTuplestoreScanState *node);
 extern void ExecEndNamedTuplestoreScan(NamedTuplestoreScanState *node);
 extern void ExecReScanNamedTuplestoreScan(NamedTuplestoreScanState *node);
 
diff --git a/src/include/executor/nodeNestloop.h b/src/include/executor/nodeNestloop.h
index 8e0fcc1922c..0d6486cc57a 100644
--- a/src/include/executor/nodeNestloop.h
+++ b/src/include/executor/nodeNestloop.h
@@ -17,7 +17,6 @@
 #include "nodes/execnodes.h"
 
 extern NestLoopState *ExecInitNestLoop(NestLoop *node, EState *estate, int eflags);
-extern TupleTableSlot *ExecNestLoop(NestLoopState *node);
 extern void ExecEndNestLoop(NestLoopState *node);
 extern void ExecReScanNestLoop(NestLoopState *node);
 
diff --git a/src/include/executor/nodeProjectSet.h b/src/include/executor/nodeProjectSet.h
index 2f6999e8db3..a0b0521f8d2 100644
--- a/src/include/executor/nodeProjectSet.h
+++ b/src/include/executor/nodeProjectSet.h
@@ -17,7 +17,6 @@
 #include "nodes/execnodes.h"
 
 extern ProjectSetState *ExecInitProjectSet(ProjectSet *node, EState *estate, int eflags);
-extern TupleTableSlot *ExecProjectSet(ProjectSetState *node);
 extern void ExecEndProjectSet(ProjectSetState *node);
 extern void ExecReScanProjectSet(ProjectSetState *node);
 
diff --git a/src/include/executor/nodeRecursiveunion.h b/src/include/executor/nodeRecursiveunion.h
index f0eba05bee9..e6ce1b47831 100644
--- a/src/include/executor/nodeRecursiveunion.h
+++ b/src/include/executor/nodeRecursiveunion.h
@@ -17,7 +17,6 @@
 #include "nodes/execnodes.h"
 
 extern RecursiveUnionState *ExecInitRecursiveUnion(RecursiveUnion *node, EState *estate, int eflags);
-extern TupleTableSlot *ExecRecursiveUnion(RecursiveUnionState *node);
 extern void ExecEndRecursiveUnion(RecursiveUnionState *node);
 extern void ExecReScanRecursiveUnion(RecursiveUnionState *node);
 
diff --git a/src/include/executor/nodeResult.h b/src/include/executor/nodeResult.h
index 61d3cb2cc2e..20e0063410e 100644
--- a/src/include/executor/nodeResult.h
+++ b/src/include/executor/nodeResult.h
@@ -17,7 +17,6 @@
 #include "nodes/execnodes.h"
 
 extern ResultState *ExecInitResult(Result *node, EState *estate, int eflags);
-extern TupleTableSlot *ExecResult(ResultState *node);
 extern void ExecEndResult(ResultState *node);
 extern void ExecResultMarkPos(ResultState *node);
 extern void ExecResultRestrPos(ResultState *node);
diff --git a/src/include/executor/nodeSamplescan.h b/src/include/executor/nodeSamplescan.h
index ed06e77e4ee..607bbd94125 100644
--- a/src/include/executor/nodeSamplescan.h
+++ b/src/include/executor/nodeSamplescan.h
@@ -17,7 +17,6 @@
 #include "nodes/execnodes.h"
 
 extern SampleScanState *ExecInitSampleScan(SampleScan *node, EState *estate, int eflags);
-extern TupleTableSlot *ExecSampleScan(SampleScanState *node);
 extern void ExecEndSampleScan(SampleScanState *node);
 extern void ExecReScanSampleScan(SampleScanState *node);
 
diff --git a/src/include/executor/nodeSeqscan.h b/src/include/executor/nodeSeqscan.h
index 06e0686b0b7..0fba79f8de6 100644
--- a/src/include/executor/nodeSeqscan.h
+++ b/src/include/executor/nodeSeqscan.h
@@ -18,7 +18,6 @@
 #include "nodes/execnodes.h"
 
 extern SeqScanState *ExecInitSeqScan(SeqScan *node, EState *estate, int eflags);
-extern TupleTableSlot *ExecSeqScan(SeqScanState *node);
 extern void ExecEndSeqScan(SeqScanState *node);
 extern void ExecReScanSeqScan(SeqScanState *node);
 
diff --git a/src/include/executor/nodeSetOp.h b/src/include/executor/nodeSetOp.h
index af859771838..c15f9450468 100644
--- a/src/include/executor/nodeSetOp.h
+++ b/src/include/executor/nodeSetOp.h
@@ -17,7 +17,6 @@
 #include "nodes/execnodes.h"
 
 extern SetOpState *ExecInitSetOp(SetOp *node, EState *estate, int eflags);
-extern TupleTableSlot *ExecSetOp(SetOpState *node);
 extern void ExecEndSetOp(SetOpState *node);
 extern void ExecReScanSetOp(SetOpState *node);
 
diff --git a/src/include/executor/nodeSort.h b/src/include/executor/nodeSort.h
index 1d2b7130b32..ed0e9dbb53e 100644
--- a/src/include/executor/nodeSort.h
+++ b/src/include/executor/nodeSort.h
@@ -17,7 +17,6 @@
 #include "nodes/execnodes.h"
 
 extern SortState *ExecInitSort(Sort *node, EState *estate, int eflags);
-extern TupleTableSlot *ExecSort(SortState *node);
 extern void ExecEndSort(SortState *node);
 extern void ExecSortMarkPos(SortState *node);
 extern void ExecSortRestrPos(SortState *node);
diff --git a/src/include/executor/nodeSubqueryscan.h b/src/include/executor/nodeSubqueryscan.h
index c852e2947f9..710e050285c 100644
--- a/src/include/executor/nodeSubqueryscan.h
+++ b/src/include/executor/nodeSubqueryscan.h
@@ -17,7 +17,6 @@
 #include "nodes/execnodes.h"
 
 extern SubqueryScanState *ExecInitSubqueryScan(SubqueryScan *node, EState *estate, int eflags);
-extern TupleTableSlot *ExecSubqueryScan(SubqueryScanState *node);
 extern void ExecEndSubqueryScan(SubqueryScanState *node);
 extern void ExecReScanSubqueryScan(SubqueryScanState *node);
 
diff --git a/src/include/executor/nodeTableFuncscan.h b/src/include/executor/nodeTableFuncscan.h
index c58156e99c2..c4672c0ac04 100644
--- a/src/include/executor/nodeTableFuncscan.h
+++ b/src/include/executor/nodeTableFuncscan.h
@@ -17,7 +17,6 @@
 #include "nodes/execnodes.h"
 
 extern TableFuncScanState *ExecInitTableFuncScan(TableFuncScan *node, EState *estate, int eflags);
-extern TupleTableSlot *ExecTableFuncScan(TableFuncScanState *node);
 extern void ExecEndTableFuncScan(TableFuncScanState *node);
 extern void ExecReScanTableFuncScan(TableFuncScanState *node);
 
diff --git a/src/include/executor/nodeTidscan.h b/src/include/executor/nodeTidscan.h
index d07ed7c8641..e68aaf38290 100644
--- a/src/include/executor/nodeTidscan.h
+++ b/src/include/executor/nodeTidscan.h
@@ -17,7 +17,6 @@
 #include "nodes/execnodes.h"
 
 extern TidScanState *ExecInitTidScan(TidScan *node, EState *estate, int eflags);
-extern TupleTableSlot *ExecTidScan(TidScanState *node);
 extern void ExecEndTidScan(TidScanState *node);
 extern void ExecReScanTidScan(TidScanState *node);
 
diff --git a/src/include/executor/nodeUnique.h b/src/include/executor/nodeUnique.h
index 3d0ac9dde16..008774ae0f0 100644
--- a/src/include/executor/nodeUnique.h
+++ b/src/include/executor/nodeUnique.h
@@ -17,7 +17,6 @@
 #include "nodes/execnodes.h"
 
 extern UniqueState *ExecInitUnique(Unique *node, EState *estate, int eflags);
-extern TupleTableSlot *ExecUnique(UniqueState *node);
 extern void ExecEndUnique(UniqueState *node);
 extern void ExecReScanUnique(UniqueState *node);
 
diff --git a/src/include/executor/nodeValuesscan.h b/src/include/executor/nodeValuesscan.h
index c28bb1acce6..772a5e9705d 100644
--- a/src/include/executor/nodeValuesscan.h
+++ b/src/include/executor/nodeValuesscan.h
@@ -17,7 +17,6 @@
 #include "nodes/execnodes.h"
 
 extern ValuesScanState *ExecInitValuesScan(ValuesScan *node, EState *estate, int eflags);
-extern TupleTableSlot *ExecValuesScan(ValuesScanState *node);
 extern void ExecEndValuesScan(ValuesScanState *node);
 extern void ExecReScanValuesScan(ValuesScanState *node);
 
diff --git a/src/include/executor/nodeWindowAgg.h b/src/include/executor/nodeWindowAgg.h
index db1ad60677a..1c177309ae6 100644
--- a/src/include/executor/nodeWindowAgg.h
+++ b/src/include/executor/nodeWindowAgg.h
@@ -17,7 +17,6 @@
 #include "nodes/execnodes.h"
 
 extern WindowAggState *ExecInitWindowAgg(WindowAgg *node, EState *estate, int eflags);
-extern TupleTableSlot *ExecWindowAgg(WindowAggState *node);
 extern void ExecEndWindowAgg(WindowAggState *node);
 extern void ExecReScanWindowAgg(WindowAggState *node);
 
diff --git a/src/include/executor/nodeWorktablescan.h b/src/include/executor/nodeWorktablescan.h
index c222d9f6b4d..df05e75111b 100644
--- a/src/include/executor/nodeWorktablescan.h
+++ b/src/include/executor/nodeWorktablescan.h
@@ -17,7 +17,6 @@
 #include "nodes/execnodes.h"
 
 extern WorkTableScanState *ExecInitWorkTableScan(WorkTableScan *node, EState *estate, int eflags);
-extern TupleTableSlot *ExecWorkTableScan(WorkTableScanState *node);
 extern void ExecEndWorkTableScan(WorkTableScanState *node);
 extern void ExecReScanWorkTableScan(WorkTableScanState *node);
 
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index 85fac8ab91b..35c28a61431 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -818,6 +818,18 @@ typedef struct DomainConstraintState
  * ----------------------------------------------------------------
  */
 
+struct PlanState;
+
+/* ----------------
+ *	 ExecProcNodeMtd
+ *
+ * This is the method called by ExecProcNode to return the next tuple
+ * from an executor node.  It returns NULL, or an empty TupleTableSlot,
+ * if no more tuples are available.
+ * ----------------
+ */
+typedef TupleTableSlot *(*ExecProcNodeMtd) (struct PlanState *pstate);
+
 /* ----------------
  *		PlanState node
  *
@@ -835,6 +847,10 @@ typedef struct PlanState
 								 * nodes point to one EState for the whole
 								 * top-level plan */
 
+	ExecProcNodeMtd ExecProcNode;	/* function to return next tuple */
+	ExecProcNodeMtd ExecProcNodeReal;	/* actual function, if above is a
+										 * wrapper */
+
 	Instrumentation *instrument;	/* Optional runtime stats for this node */
 	WorkerInstrumentation *worker_instrument;	/* per-worker instrumentation */