diff --git a/contrib/auto_explain/auto_explain.c b/contrib/auto_explain/auto_explain.c
index 623a674f99..f2eaa8e494 100644
--- a/contrib/auto_explain/auto_explain.c
+++ b/contrib/auto_explain/auto_explain.c
@@ -79,7 +79,7 @@ static ExecutorEnd_hook_type prev_ExecutorEnd = NULL;
 static void explain_ExecutorStart(QueryDesc *queryDesc, int eflags);
 static void explain_ExecutorRun(QueryDesc *queryDesc,
 								ScanDirection direction,
-								uint64 count, bool execute_once);
+								uint64 count);
 static void explain_ExecutorFinish(QueryDesc *queryDesc);
 static void explain_ExecutorEnd(QueryDesc *queryDesc);
 
@@ -321,15 +321,15 @@ explain_ExecutorStart(QueryDesc *queryDesc, int eflags)
  */
 static void
 explain_ExecutorRun(QueryDesc *queryDesc, ScanDirection direction,
-					uint64 count, bool execute_once)
+					uint64 count)
 {
 	nesting_level++;
 	PG_TRY();
 	{
 		if (prev_ExecutorRun)
-			prev_ExecutorRun(queryDesc, direction, count, execute_once);
+			prev_ExecutorRun(queryDesc, direction, count);
 		else
-			standard_ExecutorRun(queryDesc, direction, count, execute_once);
+			standard_ExecutorRun(queryDesc, direction, count);
 	}
 	PG_FINALLY();
 	{
diff --git a/contrib/pg_stat_statements/pg_stat_statements.c b/contrib/pg_stat_statements/pg_stat_statements.c
index 49c657b3e0..602cae54ff 100644
--- a/contrib/pg_stat_statements/pg_stat_statements.c
+++ b/contrib/pg_stat_statements/pg_stat_statements.c
@@ -335,7 +335,7 @@ static PlannedStmt *pgss_planner(Query *parse,
 static void pgss_ExecutorStart(QueryDesc *queryDesc, int eflags);
 static void pgss_ExecutorRun(QueryDesc *queryDesc,
 							 ScanDirection direction,
-							 uint64 count, bool execute_once);
+							 uint64 count);
 static void pgss_ExecutorFinish(QueryDesc *queryDesc);
 static void pgss_ExecutorEnd(QueryDesc *queryDesc);
 static void pgss_ProcessUtility(PlannedStmt *pstmt, const char *queryString,
@@ -1021,16 +1021,15 @@ pgss_ExecutorStart(QueryDesc *queryDesc, int eflags)
  * ExecutorRun hook: all we need do is track nesting depth
  */
 static void
-pgss_ExecutorRun(QueryDesc *queryDesc, ScanDirection direction, uint64 count,
-				 bool execute_once)
+pgss_ExecutorRun(QueryDesc *queryDesc, ScanDirection direction, uint64 count)
 {
 	nesting_level++;
 	PG_TRY();
 	{
 		if (prev_ExecutorRun)
-			prev_ExecutorRun(queryDesc, direction, count, execute_once);
+			prev_ExecutorRun(queryDesc, direction, count);
 		else
-			standard_ExecutorRun(queryDesc, direction, count, execute_once);
+			standard_ExecutorRun(queryDesc, direction, count);
 	}
 	PG_FINALLY();
 	{
diff --git a/src/backend/commands/copyto.c b/src/backend/commands/copyto.c
index f55e6d9675..161a0f8b0a 100644
--- a/src/backend/commands/copyto.c
+++ b/src/backend/commands/copyto.c
@@ -880,7 +880,7 @@ DoCopyTo(CopyToState cstate)
 	else
 	{
 		/* run the plan --- the dest receiver will send tuples */
-		ExecutorRun(cstate->queryDesc, ForwardScanDirection, 0, true);
+		ExecutorRun(cstate->queryDesc, ForwardScanDirection, 0);
 		processed = ((DR_copy *) cstate->queryDesc->dest)->processed;
 	}
 
diff --git a/src/backend/commands/createas.c b/src/backend/commands/createas.c
index 5c92e48a56..466376af9b 100644
--- a/src/backend/commands/createas.c
+++ b/src/backend/commands/createas.c
@@ -340,7 +340,7 @@ ExecCreateTableAs(ParseState *pstate, CreateTableAsStmt *stmt,
 		ExecutorStart(queryDesc, GetIntoRelEFlags(into));
 
 		/* run the plan to completion */
-		ExecutorRun(queryDesc, ForwardScanDirection, 0, true);
+		ExecutorRun(queryDesc, ForwardScanDirection, 0);
 
 		/* save the rowcount if we're given a qc to fill */
 		if (qc)
diff --git a/src/backend/commands/explain.c b/src/backend/commands/explain.c
index a3f1d53d7a..3078f5c1a3 100644
--- a/src/backend/commands/explain.c
+++ b/src/backend/commands/explain.c
@@ -719,7 +719,7 @@ ExplainOnePlan(PlannedStmt *plannedstmt, IntoClause *into, ExplainState *es,
 			dir = ForwardScanDirection;
 
 		/* run the plan */
-		ExecutorRun(queryDesc, dir, 0, true);
+		ExecutorRun(queryDesc, dir, 0);
 
 		/* run cleanup too */
 		ExecutorFinish(queryDesc);
diff --git a/src/backend/commands/extension.c b/src/backend/commands/extension.c
index af6bd8ff42..e683c520a8 100644
--- a/src/backend/commands/extension.c
+++ b/src/backend/commands/extension.c
@@ -912,7 +912,7 @@ execute_sql_string(const char *sql, const char *filename)
 										dest, NULL, NULL, 0);
 
 				ExecutorStart(qdesc, 0);
-				ExecutorRun(qdesc, ForwardScanDirection, 0, true);
+				ExecutorRun(qdesc, ForwardScanDirection, 0);
 				ExecutorFinish(qdesc);
 				ExecutorEnd(qdesc);
 
diff --git a/src/backend/commands/matview.c b/src/backend/commands/matview.c
index 010097873d..694da8291e 100644
--- a/src/backend/commands/matview.c
+++ b/src/backend/commands/matview.c
@@ -446,7 +446,7 @@ refresh_matview_datafill(DestReceiver *dest, Query *query,
 	ExecutorStart(queryDesc, 0);
 
 	/* run the plan */
-	ExecutorRun(queryDesc, ForwardScanDirection, 0, true);
+	ExecutorRun(queryDesc, ForwardScanDirection, 0);
 
 	processed = queryDesc->estate->es_processed;
 
diff --git a/src/backend/commands/portalcmds.c b/src/backend/commands/portalcmds.c
index ac52ca25e9..dc68264242 100644
--- a/src/backend/commands/portalcmds.c
+++ b/src/backend/commands/portalcmds.c
@@ -427,7 +427,7 @@ PersistHoldablePortal(Portal portal)
 										NULL);
 
 		/* Fetch the result set into the tuplestore */
-		ExecutorRun(queryDesc, direction, 0, false);
+		ExecutorRun(queryDesc, direction, 0);
 
 		queryDesc->dest->rDestroy(queryDesc->dest);
 		queryDesc->dest = NULL;
diff --git a/src/backend/commands/prepare.c b/src/backend/commands/prepare.c
index a93f970a29..39a71c1de2 100644
--- a/src/backend/commands/prepare.c
+++ b/src/backend/commands/prepare.c
@@ -252,7 +252,7 @@ ExecuteQuery(ParseState *pstate,
 	 */
 	PortalStart(portal, paramLI, eflags, GetActiveSnapshot());
 
-	(void) PortalRun(portal, count, false, true, dest, dest, qc);
+	(void) PortalRun(portal, count, false, dest, dest, qc);
 
 	PortalDrop(portal, false);
 
diff --git a/src/backend/executor/execMain.c b/src/backend/executor/execMain.c
index 5ca856fd27..312f622f32 100644
--- a/src/backend/executor/execMain.c
+++ b/src/backend/executor/execMain.c
@@ -77,14 +77,13 @@ static void InitPlan(QueryDesc *queryDesc, int eflags);
 static void CheckValidRowMarkRel(Relation rel, RowMarkType markType);
 static void ExecPostprocessPlan(EState *estate);
 static void ExecEndPlan(PlanState *planstate, EState *estate);
-static void ExecutePlan(EState *estate, PlanState *planstate,
+static void ExecutePlan(QueryDesc *queryDesc,
 						bool use_parallel_mode,
 						CmdType operation,
 						bool sendTuples,
 						uint64 numberTuples,
 						ScanDirection direction,
-						DestReceiver *dest,
-						bool execute_once);
+						DestReceiver *dest);
 static bool ExecCheckOneRelPerms(RTEPermissionInfo *perminfo);
 static bool ExecCheckPermissionsModified(Oid relOid, Oid userid,
 										 Bitmapset *modifiedCols,
@@ -294,18 +293,17 @@ standard_ExecutorStart(QueryDesc *queryDesc, int eflags)
  */
 void
 ExecutorRun(QueryDesc *queryDesc,
-			ScanDirection direction, uint64 count,
-			bool execute_once)
+			ScanDirection direction, uint64 count)
 {
 	if (ExecutorRun_hook)
-		(*ExecutorRun_hook) (queryDesc, direction, count, execute_once);
+		(*ExecutorRun_hook) (queryDesc, direction, count);
 	else
-		standard_ExecutorRun(queryDesc, direction, count, execute_once);
+		standard_ExecutorRun(queryDesc, direction, count);
 }
 
 void
 standard_ExecutorRun(QueryDesc *queryDesc,
-					 ScanDirection direction, uint64 count, bool execute_once)
+					 ScanDirection direction, uint64 count)
 {
 	EState	   *estate;
 	CmdType		operation;
@@ -354,21 +352,13 @@ standard_ExecutorRun(QueryDesc *queryDesc,
 	 * run plan
 	 */
 	if (!ScanDirectionIsNoMovement(direction))
-	{
-		if (execute_once && queryDesc->already_executed)
-			elog(ERROR, "can't re-execute query flagged for single execution");
-		queryDesc->already_executed = true;
-
-		ExecutePlan(estate,
-					queryDesc->planstate,
+		ExecutePlan(queryDesc,
 					queryDesc->plannedstmt->parallelModeNeeded,
 					operation,
 					sendTuples,
 					count,
 					direction,
-					dest,
-					execute_once);
-	}
+					dest);
 
 	/*
 	 * Update es_total_processed to keep track of the number of tuples
@@ -1601,22 +1591,19 @@ ExecCloseRangeTableRelations(EState *estate)
  *		moving in the specified direction.
  *
  *		Runs to completion if numberTuples is 0
- *
- * Note: the ctid attribute is a 'junk' attribute that is removed before the
- * user can see it
  * ----------------------------------------------------------------
  */
 static void
-ExecutePlan(EState *estate,
-			PlanState *planstate,
+ExecutePlan(QueryDesc *queryDesc,
 			bool use_parallel_mode,
 			CmdType operation,
 			bool sendTuples,
 			uint64 numberTuples,
 			ScanDirection direction,
-			DestReceiver *dest,
-			bool execute_once)
+			DestReceiver *dest)
 {
+	EState	   *estate = queryDesc->estate;
+	PlanState  *planstate = queryDesc->planstate;
 	TupleTableSlot *slot;
 	uint64		current_tuple_count;
 
@@ -1631,11 +1618,13 @@ ExecutePlan(EState *estate,
 	estate->es_direction = direction;
 
 	/*
-	 * If the plan might potentially be executed multiple times, we must force
-	 * it to run without parallelism, because we might exit early.
+	 * Parallel mode only supports complete execution of a plan.  If we've
+	 * already partially executed it, or if the caller asks us to exit early,
+	 * we must force the plan to run without parallelism.
 	 */
-	if (!execute_once)
+	if (queryDesc->already_executed || numberTuples != 0)
 		use_parallel_mode = false;
+	queryDesc->already_executed = true;
 
 	estate->es_use_parallel_mode = use_parallel_mode;
 	if (use_parallel_mode)
diff --git a/src/backend/executor/execParallel.c b/src/backend/executor/execParallel.c
index bfb3419efb..846ec727de 100644
--- a/src/backend/executor/execParallel.c
+++ b/src/backend/executor/execParallel.c
@@ -1471,8 +1471,7 @@ ParallelQueryMain(dsm_segment *seg, shm_toc *toc)
 	 */
 	ExecutorRun(queryDesc,
 				ForwardScanDirection,
-				fpes->tuples_needed < 0 ? (int64) 0 : fpes->tuples_needed,
-				true);
+				fpes->tuples_needed < 0 ? (int64) 0 : fpes->tuples_needed);
 
 	/* Shut down the executor */
 	ExecutorFinish(queryDesc);
diff --git a/src/backend/executor/functions.c b/src/backend/executor/functions.c
index 8d1fda2ddc..3b2f78b219 100644
--- a/src/backend/executor/functions.c
+++ b/src/backend/executor/functions.c
@@ -894,7 +894,7 @@ postquel_getnext(execution_state *es, SQLFunctionCachePtr fcache)
 		/* Run regular commands to completion unless lazyEval */
 		uint64		count = (es->lazyEval) ? 1 : 0;
 
-		ExecutorRun(es->qd, ForwardScanDirection, count, !fcache->returnsSet || !es->lazyEval);
+		ExecutorRun(es->qd, ForwardScanDirection, count);
 
 		/*
 		 * If we requested run to completion OR there was no tuple returned,
diff --git a/src/backend/executor/spi.c b/src/backend/executor/spi.c
index 2fb2e73604..c1d8fd08c6 100644
--- a/src/backend/executor/spi.c
+++ b/src/backend/executor/spi.c
@@ -2929,7 +2929,7 @@ _SPI_pquery(QueryDesc *queryDesc, bool fire_triggers, uint64 tcount)
 
 	ExecutorStart(queryDesc, eflags);
 
-	ExecutorRun(queryDesc, ForwardScanDirection, tcount, true);
+	ExecutorRun(queryDesc, ForwardScanDirection, tcount);
 
 	_SPI_current->processed = queryDesc->estate->es_processed;
 
diff --git a/src/backend/tcop/postgres.c b/src/backend/tcop/postgres.c
index 42af768045..e0a603f42b 100644
--- a/src/backend/tcop/postgres.c
+++ b/src/backend/tcop/postgres.c
@@ -1283,7 +1283,6 @@ exec_simple_query(const char *query_string)
 		(void) PortalRun(portal,
 						 FETCH_ALL,
 						 true,	/* always top level */
-						 true,
 						 receiver,
 						 receiver,
 						 &qc);
@@ -2260,7 +2259,6 @@ exec_execute_message(const char *portal_name, long max_rows)
 	completed = PortalRun(portal,
 						  max_rows,
 						  true, /* always top level */
-						  !execute_is_fetch && max_rows == FETCH_ALL,
 						  receiver,
 						  receiver,
 						  &qc);
diff --git a/src/backend/tcop/pquery.c b/src/backend/tcop/pquery.c
index 0c45fcf318..89d704df8d 100644
--- a/src/backend/tcop/pquery.c
+++ b/src/backend/tcop/pquery.c
@@ -157,7 +157,7 @@ ProcessQuery(PlannedStmt *plan,
 	/*
 	 * Run the plan to completion.
 	 */
-	ExecutorRun(queryDesc, ForwardScanDirection, 0, true);
+	ExecutorRun(queryDesc, ForwardScanDirection, 0);
 
 	/*
 	 * Build command completion status data, if caller wants one.
@@ -681,7 +681,7 @@ PortalSetResultFormat(Portal portal, int nFormats, int16 *formats)
  * suspended due to exhaustion of the count parameter.
  */
 bool
-PortalRun(Portal portal, long count, bool isTopLevel, bool run_once,
+PortalRun(Portal portal, long count, bool isTopLevel,
 		  DestReceiver *dest, DestReceiver *altdest,
 		  QueryCompletion *qc)
 {
@@ -714,10 +714,6 @@ PortalRun(Portal portal, long count, bool isTopLevel, bool run_once,
 	 */
 	MarkPortalActive(portal);
 
-	/* Set run_once flag.  Shouldn't be clear if previously set. */
-	Assert(!portal->run_once || run_once);
-	portal->run_once = run_once;
-
 	/*
 	 * Set up global portal context pointers.
 	 *
@@ -921,8 +917,7 @@ PortalRunSelect(Portal portal,
 		else
 		{
 			PushActiveSnapshot(queryDesc->snapshot);
-			ExecutorRun(queryDesc, direction, (uint64) count,
-						portal->run_once);
+			ExecutorRun(queryDesc, direction, (uint64) count);
 			nprocessed = queryDesc->estate->es_processed;
 			PopActiveSnapshot();
 		}
@@ -961,8 +956,7 @@ PortalRunSelect(Portal portal,
 		else
 		{
 			PushActiveSnapshot(queryDesc->snapshot);
-			ExecutorRun(queryDesc, direction, (uint64) count,
-						portal->run_once);
+			ExecutorRun(queryDesc, direction, (uint64) count);
 			nprocessed = queryDesc->estate->es_processed;
 			PopActiveSnapshot();
 		}
@@ -1406,9 +1400,6 @@ PortalRunFetch(Portal portal,
 	 */
 	MarkPortalActive(portal);
 
-	/* If supporting FETCH, portal can't be run-once. */
-	Assert(!portal->run_once);
-
 	/*
 	 * Set up global portal context pointers.
 	 */
diff --git a/src/include/executor/execdesc.h b/src/include/executor/execdesc.h
index 0a7274e26c..79e8b63111 100644
--- a/src/include/executor/execdesc.h
+++ b/src/include/executor/execdesc.h
@@ -48,7 +48,7 @@ typedef struct QueryDesc
 	EState	   *estate;			/* executor's query-wide state */
 	PlanState  *planstate;		/* tree of per-plan-node state */
 
-	/* This field is set by ExecutorRun */
+	/* This field is set by ExecutePlan */
 	bool		already_executed;	/* true if previously executed */
 
 	/* This is always set NULL by the core system, but plugins can change it */
diff --git a/src/include/executor/executor.h b/src/include/executor/executor.h
index 69c3ebff00..892cf055cd 100644
--- a/src/include/executor/executor.h
+++ b/src/include/executor/executor.h
@@ -78,8 +78,7 @@ extern PGDLLIMPORT ExecutorStart_hook_type ExecutorStart_hook;
 /* Hook for plugins to get control in ExecutorRun() */
 typedef void (*ExecutorRun_hook_type) (QueryDesc *queryDesc,
 									   ScanDirection direction,
-									   uint64 count,
-									   bool execute_once);
+									   uint64 count);
 extern PGDLLIMPORT ExecutorRun_hook_type ExecutorRun_hook;
 
 /* Hook for plugins to get control in ExecutorFinish() */
@@ -200,9 +199,9 @@ ExecGetJunkAttribute(TupleTableSlot *slot, AttrNumber attno, bool *isNull)
 extern void ExecutorStart(QueryDesc *queryDesc, int eflags);
 extern void standard_ExecutorStart(QueryDesc *queryDesc, int eflags);
 extern void ExecutorRun(QueryDesc *queryDesc,
-						ScanDirection direction, uint64 count, bool execute_once);
+						ScanDirection direction, uint64 count);
 extern void standard_ExecutorRun(QueryDesc *queryDesc,
-								 ScanDirection direction, uint64 count, bool execute_once);
+								 ScanDirection direction, uint64 count);
 extern void ExecutorFinish(QueryDesc *queryDesc);
 extern void standard_ExecutorFinish(QueryDesc *queryDesc);
 extern void ExecutorEnd(QueryDesc *queryDesc);
diff --git a/src/include/tcop/pquery.h b/src/include/tcop/pquery.h
index 073fb323bc..37ba3160e5 100644
--- a/src/include/tcop/pquery.h
+++ b/src/include/tcop/pquery.h
@@ -36,7 +36,7 @@ extern void PortalSetResultFormat(Portal portal, int nFormats,
 								  int16 *formats);
 
 extern bool PortalRun(Portal portal, long count, bool isTopLevel,
-					  bool run_once, DestReceiver *dest, DestReceiver *altdest,
+					  DestReceiver *dest, DestReceiver *altdest,
 					  QueryCompletion *qc);
 
 extern uint64 PortalRunFetch(Portal portal,
diff --git a/src/include/utils/portal.h b/src/include/utils/portal.h
index 29f49829f2..afe605a8ed 100644
--- a/src/include/utils/portal.h
+++ b/src/include/utils/portal.h
@@ -145,7 +145,6 @@ typedef struct PortalData
 	/* Features/options */
 	PortalStrategy strategy;	/* see above */
 	int			cursorOptions;	/* DECLARE CURSOR option bits */
-	bool		run_once;		/* portal will only be run once */
 
 	/* Status data */
 	PortalStatus status;		/* see above */