diff --git a/src/backend/executor/execScan.c b/src/backend/executor/execScan.c
index 69ab34573e..9f1d8b6d1e 100644
--- a/src/backend/executor/execScan.c
+++ b/src/backend/executor/execScan.c
@@ -282,7 +282,7 @@ ExecAssignScanProjectionInfo(ScanState *node)
  *		As above, but caller can specify varno expected in Vars in the tlist.
  */
 void
-ExecAssignScanProjectionInfoWithVarno(ScanState *node, Index varno)
+ExecAssignScanProjectionInfoWithVarno(ScanState *node, int varno)
 {
 	TupleDesc	tupdesc = node->ss_ScanTupleSlot->tts_tupleDescriptor;
 
diff --git a/src/backend/executor/execUtils.c b/src/backend/executor/execUtils.c
index ad11392b99..4ab1302313 100644
--- a/src/backend/executor/execUtils.c
+++ b/src/backend/executor/execUtils.c
@@ -65,7 +65,7 @@
 #include "utils/typcache.h"
 
 
-static bool tlist_matches_tupdesc(PlanState *ps, List *tlist, Index varno, TupleDesc tupdesc);
+static bool tlist_matches_tupdesc(PlanState *ps, List *tlist, int varno, TupleDesc tupdesc);
 static void ShutdownExprContext(ExprContext *econtext, bool isCommit);
 
 
@@ -553,7 +553,7 @@ ExecAssignProjectionInfo(PlanState *planstate,
  */
 void
 ExecConditionalAssignProjectionInfo(PlanState *planstate, TupleDesc inputDesc,
-									Index varno)
+									int varno)
 {
 	if (tlist_matches_tupdesc(planstate,
 							  planstate->plan->targetlist,
@@ -579,7 +579,7 @@ ExecConditionalAssignProjectionInfo(PlanState *planstate, TupleDesc inputDesc,
 }
 
 static bool
-tlist_matches_tupdesc(PlanState *ps, List *tlist, Index varno, TupleDesc tupdesc)
+tlist_matches_tupdesc(PlanState *ps, List *tlist, int varno, TupleDesc tupdesc)
 {
 	int			numattrs = tupdesc->natts;
 	int			attrno;
diff --git a/src/backend/executor/nodeCustom.c b/src/backend/executor/nodeCustom.c
index c82060e6d1..1dfa53c381 100644
--- a/src/backend/executor/nodeCustom.c
+++ b/src/backend/executor/nodeCustom.c
@@ -31,7 +31,7 @@ ExecInitCustomScan(CustomScan *cscan, EState *estate, int eflags)
 	CustomScanState *css;
 	Relation	scan_rel = NULL;
 	Index		scanrelid = cscan->scan.scanrelid;
-	Index		tlistvarno;
+	int			tlistvarno;
 
 	/*
 	 * Allocate the CustomScanState object.  We let the custom scan provider
diff --git a/src/backend/executor/nodeForeignscan.c b/src/backend/executor/nodeForeignscan.c
index 1abd906b16..0a549afcc0 100644
--- a/src/backend/executor/nodeForeignscan.c
+++ b/src/backend/executor/nodeForeignscan.c
@@ -138,7 +138,7 @@ ExecInitForeignScan(ForeignScan *node, EState *estate, int eflags)
 	ForeignScanState *scanstate;
 	Relation	currentRelation = NULL;
 	Index		scanrelid = node->scan.scanrelid;
-	Index		tlistvarno;
+	int			tlistvarno;
 	FdwRoutine *fdwroutine;
 
 	/* check for unsupported flags */
diff --git a/src/backend/nodes/makefuncs.c b/src/backend/nodes/makefuncs.c
index 01c110cd2f..7d1a01d1ed 100644
--- a/src/backend/nodes/makefuncs.c
+++ b/src/backend/nodes/makefuncs.c
@@ -63,7 +63,7 @@ makeSimpleA_Expr(A_Expr_Kind kind, char *name,
  *	  creates a Var node
  */
 Var *
-makeVar(Index varno,
+makeVar(int varno,
 		AttrNumber varattno,
 		Oid vartype,
 		int32 vartypmod,
@@ -85,7 +85,7 @@ makeVar(Index varno,
 	 * them, but just initialize them to the given varno/varattno.  This
 	 * reduces code clutter and chance of error for most callers.
 	 */
-	var->varnosyn = varno;
+	var->varnosyn = (Index) varno;
 	var->varattnosyn = varattno;
 
 	/* Likewise, we just set location to "unknown" here */
@@ -100,7 +100,7 @@ makeVar(Index varno,
  *		TargetEntry
  */
 Var *
-makeVarFromTargetEntry(Index varno,
+makeVarFromTargetEntry(int varno,
 					   TargetEntry *tle)
 {
 	return makeVar(varno,
@@ -131,7 +131,7 @@ makeVarFromTargetEntry(Index varno,
  */
 Var *
 makeWholeRowVar(RangeTblEntry *rte,
-				Index varno,
+				int varno,
 				Index varlevelsup,
 				bool allowScalar)
 {
diff --git a/src/backend/nodes/outfuncs.c b/src/backend/nodes/outfuncs.c
index 6b290737a6..2e5ed77e18 100644
--- a/src/backend/nodes/outfuncs.c
+++ b/src/backend/nodes/outfuncs.c
@@ -1123,7 +1123,7 @@ _outVar(StringInfo str, const Var *node)
 {
 	WRITE_NODE_TYPE("VAR");
 
-	WRITE_UINT_FIELD(varno);
+	WRITE_INT_FIELD(varno);
 	WRITE_INT_FIELD(varattno);
 	WRITE_OID_FIELD(vartype);
 	WRITE_INT_FIELD(vartypmod);
diff --git a/src/backend/nodes/readfuncs.c b/src/backend/nodes/readfuncs.c
index 01aee85bd4..abf08b7a2f 100644
--- a/src/backend/nodes/readfuncs.c
+++ b/src/backend/nodes/readfuncs.c
@@ -577,7 +577,7 @@ _readVar(void)
 {
 	READ_LOCALS(Var);
 
-	READ_UINT_FIELD(varno);
+	READ_INT_FIELD(varno);
 	READ_INT_FIELD(varattno);
 	READ_OID_FIELD(vartype);
 	READ_INT_FIELD(vartypmod);
diff --git a/src/backend/optimizer/path/costsize.c b/src/backend/optimizer/path/costsize.c
index 1fd53b40bb..1e4d404f02 100644
--- a/src/backend/optimizer/path/costsize.c
+++ b/src/backend/optimizer/path/costsize.c
@@ -5961,7 +5961,8 @@ set_pathtarget_cost_width(PlannerInfo *root, PathTarget *target)
 			Assert(var->varlevelsup == 0);
 
 			/* Try to get data from RelOptInfo cache */
-			if (var->varno < root->simple_rel_array_size)
+			if (!IS_SPECIAL_VARNO(var->varno) &&
+				var->varno < root->simple_rel_array_size)
 			{
 				RelOptInfo *rel = root->simple_rel_array[var->varno];
 
diff --git a/src/backend/optimizer/plan/createplan.c b/src/backend/optimizer/plan/createplan.c
index a5f6d678cc..3dc0176a51 100644
--- a/src/backend/optimizer/plan/createplan.c
+++ b/src/backend/optimizer/plan/createplan.c
@@ -4805,7 +4805,8 @@ replace_nestloop_params_mutator(Node *node, PlannerInfo *root)
 		/* Upper-level Vars should be long gone at this point */
 		Assert(var->varlevelsup == 0);
 		/* If not to be replaced, we can just return the Var unmodified */
-		if (!bms_is_member(var->varno, root->curOuterRels))
+		if (IS_SPECIAL_VARNO(var->varno) ||
+			!bms_is_member(var->varno, root->curOuterRels))
 			return node;
 		/* Replace the Var with a nestloop Param */
 		return (Node *) replace_nestloop_param_var(root, var);
diff --git a/src/backend/optimizer/plan/setrefs.c b/src/backend/optimizer/plan/setrefs.c
index 3d23a2e5ac..6ccec759bd 100644
--- a/src/backend/optimizer/plan/setrefs.c
+++ b/src/backend/optimizer/plan/setrefs.c
@@ -31,7 +31,7 @@
 
 typedef struct
 {
-	Index		varno;			/* RT index of Var */
+	int			varno;			/* RT index of Var */
 	AttrNumber	varattno;		/* attr number of Var */
 	AttrNumber	resno;			/* TLE position of Var */
 } tlist_vinfo;
@@ -66,7 +66,7 @@ typedef struct
 {
 	PlannerInfo *root;
 	indexed_tlist *subplan_itlist;
-	Index		newvarno;
+	int			newvarno;
 	int			rtoffset;
 	double		num_exec;
 } fix_upper_expr_context;
@@ -143,15 +143,15 @@ static void set_dummy_tlist_references(Plan *plan, int rtoffset);
 static indexed_tlist *build_tlist_index(List *tlist);
 static Var *search_indexed_tlist_for_var(Var *var,
 										 indexed_tlist *itlist,
-										 Index newvarno,
+										 int newvarno,
 										 int rtoffset);
 static Var *search_indexed_tlist_for_non_var(Expr *node,
 											 indexed_tlist *itlist,
-											 Index newvarno);
+											 int newvarno);
 static Var *search_indexed_tlist_for_sortgroupref(Expr *node,
 												  Index sortgroupref,
 												  indexed_tlist *itlist,
-												  Index newvarno);
+												  int newvarno);
 static List *fix_join_expr(PlannerInfo *root,
 						   List *clauses,
 						   indexed_tlist *outer_itlist,
@@ -163,7 +163,7 @@ static Node *fix_join_expr_mutator(Node *node,
 static Node *fix_upper_expr(PlannerInfo *root,
 							Node *node,
 							indexed_tlist *subplan_itlist,
-							Index newvarno,
+							int newvarno,
 							int rtoffset, double num_exec);
 static Node *fix_upper_expr_mutator(Node *node,
 									fix_upper_expr_context *context);
@@ -505,16 +505,6 @@ add_rte_to_flat_rtable(PlannerGlobal *glob, RangeTblEntry *rte)
 
 	glob->finalrtable = lappend(glob->finalrtable, newrte);
 
-	/*
-	 * Check for RT index overflow; it's very unlikely, but if it did happen,
-	 * the executor would get confused by varnos that match the special varno
-	 * values.
-	 */
-	if (IS_SPECIAL_VARNO(list_length(glob->finalrtable)))
-		ereport(ERROR,
-				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
-				 errmsg("too many range table entries")));
-
 	/*
 	 * If it's a plain relation RTE, add the table to relationOids.
 	 *
@@ -1947,10 +1937,8 @@ fix_scan_expr_mutator(Node *node, fix_scan_expr_context *context)
 	{
 		CurrentOfExpr *cexpr = (CurrentOfExpr *) copyObject(node);
 
-		Assert(cexpr->cvarno != INNER_VAR);
-		Assert(cexpr->cvarno != OUTER_VAR);
-		if (!IS_SPECIAL_VARNO(cexpr->cvarno))
-			cexpr->cvarno += context->rtoffset;
+		Assert(!IS_SPECIAL_VARNO(cexpr->cvarno));
+		cexpr->cvarno += context->rtoffset;
 		return (Node *) cexpr;
 	}
 	if (IsA(node, PlaceHolderVar))
@@ -2447,7 +2435,7 @@ build_tlist_index(List *tlist)
  * (so nothing other than Vars and PlaceHolderVars can be matched).
  */
 static indexed_tlist *
-build_tlist_index_other_vars(List *tlist, Index ignore_rel)
+build_tlist_index_other_vars(List *tlist, int ignore_rel)
 {
 	indexed_tlist *itlist;
 	tlist_vinfo *vinfo;
@@ -2499,9 +2487,9 @@ build_tlist_index_other_vars(List *tlist, Index ignore_rel)
  */
 static Var *
 search_indexed_tlist_for_var(Var *var, indexed_tlist *itlist,
-							 Index newvarno, int rtoffset)
+							 int newvarno, int rtoffset)
 {
-	Index		varno = var->varno;
+	int			varno = var->varno;
 	AttrNumber	varattno = var->varattno;
 	tlist_vinfo *vinfo;
 	int			i;
@@ -2539,7 +2527,7 @@ search_indexed_tlist_for_var(Var *var, indexed_tlist *itlist,
  */
 static Var *
 search_indexed_tlist_for_non_var(Expr *node,
-								 indexed_tlist *itlist, Index newvarno)
+								 indexed_tlist *itlist, int newvarno)
 {
 	TargetEntry *tle;
 
@@ -2581,7 +2569,7 @@ static Var *
 search_indexed_tlist_for_sortgroupref(Expr *node,
 									  Index sortgroupref,
 									  indexed_tlist *itlist,
-									  Index newvarno)
+									  int newvarno)
 {
 	ListCell   *lc;
 
@@ -2799,7 +2787,7 @@ static Node *
 fix_upper_expr(PlannerInfo *root,
 			   Node *node,
 			   indexed_tlist *subplan_itlist,
-			   Index newvarno,
+			   int newvarno,
 			   int rtoffset,
 			   double num_exec)
 {
diff --git a/src/backend/optimizer/prep/prepjointree.c b/src/backend/optimizer/prep/prepjointree.c
index 224c5153b1..387a35e112 100644
--- a/src/backend/optimizer/prep/prepjointree.c
+++ b/src/backend/optimizer/prep/prepjointree.c
@@ -80,7 +80,7 @@ static Node *pull_up_simple_union_all(PlannerInfo *root, Node *jtnode,
 static void pull_up_union_leaf_queries(Node *setOp, PlannerInfo *root,
 									   int parentRTindex, Query *setOpQuery,
 									   int childRToffset);
-static void make_setop_translation_list(Query *query, Index newvarno,
+static void make_setop_translation_list(Query *query, int newvarno,
 										AppendRelInfo *appinfo);
 static bool is_simple_subquery(PlannerInfo *root, Query *subquery,
 							   RangeTblEntry *rte,
@@ -1372,7 +1372,7 @@ pull_up_union_leaf_queries(Node *setOp, PlannerInfo *root, int parentRTindex,
  *	  Also create the rather trivial reverse-translation array.
  */
 static void
-make_setop_translation_list(Query *query, Index newvarno,
+make_setop_translation_list(Query *query, int newvarno,
 							AppendRelInfo *appinfo)
 {
 	List	   *vars = NIL;
diff --git a/src/backend/utils/adt/ruleutils.c b/src/backend/utils/adt/ruleutils.c
index ccd2835c22..b932a83827 100644
--- a/src/backend/utils/adt/ruleutils.c
+++ b/src/backend/utils/adt/ruleutils.c
@@ -6949,7 +6949,7 @@ get_variable(Var *var, int levelsup, bool istoplevel, deparse_context *context)
 	AttrNumber	attnum;
 	int			netlevelsup;
 	deparse_namespace *dpns;
-	Index		varno;
+	int			varno;
 	AttrNumber	varattno;
 	deparse_columns *colinfo;
 	char	   *refname;
@@ -6995,7 +6995,7 @@ get_variable(Var *var, int levelsup, bool istoplevel, deparse_context *context)
 		 */
 		if (context->appendparents && dpns->appendrels)
 		{
-			Index		pvarno = varno;
+			int			pvarno = varno;
 			AttrNumber	pvarattno = varattno;
 			AppendRelInfo *appinfo = dpns->appendrels[pvarno];
 			bool		found = false;
@@ -7305,7 +7305,7 @@ get_name_for_var_field(Var *var, int fieldno,
 	AttrNumber	attnum;
 	int			netlevelsup;
 	deparse_namespace *dpns;
-	Index		varno;
+	int			varno;
 	AttrNumber	varattno;
 	TupleDesc	tupleDesc;
 	Node	   *expr;
diff --git a/src/include/executor/executor.h b/src/include/executor/executor.h
index 3dc03c913e..cd57a704ad 100644
--- a/src/include/executor/executor.h
+++ b/src/include/executor/executor.h
@@ -459,7 +459,7 @@ typedef bool (*ExecScanRecheckMtd) (ScanState *node, TupleTableSlot *slot);
 extern TupleTableSlot *ExecScan(ScanState *node, ExecScanAccessMtd accessMtd,
 								ExecScanRecheckMtd recheckMtd);
 extern void ExecAssignScanProjectionInfo(ScanState *node);
-extern void ExecAssignScanProjectionInfoWithVarno(ScanState *node, Index varno);
+extern void ExecAssignScanProjectionInfoWithVarno(ScanState *node, int varno);
 extern void ExecScanReScan(ScanState *node);
 
 /*
@@ -552,7 +552,7 @@ extern const TupleTableSlotOps *ExecGetResultSlotOps(PlanState *planstate,
 extern void ExecAssignProjectionInfo(PlanState *planstate,
 									 TupleDesc inputDesc);
 extern void ExecConditionalAssignProjectionInfo(PlanState *planstate,
-												TupleDesc inputDesc, Index varno);
+												TupleDesc inputDesc, int varno);
 extern void ExecFreeExprContext(PlanState *planstate);
 extern void ExecAssignScanType(ScanState *scanstate, TupleDesc tupDesc);
 extern void ExecCreateScanSlotFromOuterPlan(EState *estate,
diff --git a/src/include/nodes/makefuncs.h b/src/include/nodes/makefuncs.h
index 48a7ebfe45..eea87f847d 100644
--- a/src/include/nodes/makefuncs.h
+++ b/src/include/nodes/makefuncs.h
@@ -24,18 +24,18 @@ extern A_Expr *makeA_Expr(A_Expr_Kind kind, List *name,
 extern A_Expr *makeSimpleA_Expr(A_Expr_Kind kind, char *name,
 								Node *lexpr, Node *rexpr, int location);
 
-extern Var *makeVar(Index varno,
+extern Var *makeVar(int varno,
 					AttrNumber varattno,
 					Oid vartype,
 					int32 vartypmod,
 					Oid varcollid,
 					Index varlevelsup);
 
-extern Var *makeVarFromTargetEntry(Index varno,
+extern Var *makeVarFromTargetEntry(int varno,
 								   TargetEntry *tle);
 
 extern Var *makeWholeRowVar(RangeTblEntry *rte,
-							Index varno,
+							int varno,
 							Index varlevelsup,
 							bool allowScalar);
 
diff --git a/src/include/nodes/primnodes.h b/src/include/nodes/primnodes.h
index 7b125904b4..433437643e 100644
--- a/src/include/nodes/primnodes.h
+++ b/src/include/nodes/primnodes.h
@@ -172,12 +172,12 @@ typedef struct Expr
  * in the planner and doesn't correspond to any simple relation column may
  * have varnosyn = varattnosyn = 0.
  */
-#define    INNER_VAR		65000	/* reference to inner subplan */
-#define    OUTER_VAR		65001	/* reference to outer subplan */
-#define    INDEX_VAR		65002	/* reference to index column */
-#define    ROWID_VAR		65003	/* row identity column during planning */
+#define    INNER_VAR		(-1)	/* reference to inner subplan */
+#define    OUTER_VAR		(-2)	/* reference to outer subplan */
+#define    INDEX_VAR		(-3)	/* reference to index column */
+#define    ROWID_VAR		(-4)	/* row identity column during planning */
 
-#define IS_SPECIAL_VARNO(varno)		((varno) >= INNER_VAR)
+#define IS_SPECIAL_VARNO(varno)		((int) (varno) < 0)
 
 /* Symbols for the indexes of the special RTE entries in rules */
 #define    PRS2_OLD_VARNO			1
@@ -186,8 +186,8 @@ typedef struct Expr
 typedef struct Var
 {
 	Expr		xpr;
-	Index		varno;			/* index of this var's relation in the range
-								 * table, or INNER_VAR/OUTER_VAR/INDEX_VAR */
+	int			varno;			/* index of this var's relation in the range
+								 * table, or INNER_VAR/OUTER_VAR/etc */
 	AttrNumber	varattno;		/* attribute number of this var, or zero for
 								 * all attrs ("whole-row Var") */
 	Oid			vartype;		/* pg_type OID for the type of this var */
@@ -1351,6 +1351,7 @@ typedef struct SetToDefault
  * of the target relation being constrained; this aids placing the expression
  * correctly during planning.  We can assume however that its "levelsup" is
  * always zero, due to the syntactic constraints on where it can appear.
+ * Also, cvarno will always be a true RT index, never INNER_VAR etc.
  *
  * The referenced cursor can be represented either as a hardwired string
  * or as a reference to a run-time parameter of type REFCURSOR.  The latter