Reimplementation of UNION/INTERSECT/EXCEPT. INTERSECT/EXCEPT now meet the

SQL92 semantics, including support for ALL option.  All three can be used
in subqueries and views.  DISTINCT and ORDER BY work now in views, too.
This rewrite fixes many problems with cross-datatype UNIONs and INSERT/SELECT
where the SELECT yields different datatypes than the INSERT needs.  I did
that by making UNION subqueries and SELECT in INSERT be treated like
subselects-in-FROM, thereby allowing an extra level of targetlist where the
datatype conversions can be inserted safely.
INITDB NEEDED!

5 files changed, 187 insertions, 142 deletions

diff --git a/src/backend/optimizer/plan/createplan.c b/src/backend/optimizer/plan/createplan.c
index cc308b4fc96..eb005121cd5 100644
--- a/src/backend/optimizer/plan/createplan.c
+++ b/src/backend/optimizer/plan/createplan.c
@@ -10,7 +10,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/optimizer/plan/createplan.c,v 1.97 2000/09/29 18:21:33 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/optimizer/plan/createplan.c,v 1.98 2000/10/05 19:11:29 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -68,8 +68,6 @@ static IndexScan *make_indexscan(List *qptlist, List *qpqual, Index scanrelid,
 			   ScanDirection indexscandir);
 static TidScan *make_tidscan(List *qptlist, List *qpqual, Index scanrelid,
 			 List *tideval);
-static SubqueryScan *make_subqueryscan(List *qptlist, List *qpqual,
-									   Index scanrelid, Plan *subplan);
 static NestLoop *make_nestloop(List *tlist,
 							   List *joinclauses, List *otherclauses,
 							   Plan *lefttree, Plan *righttree,
@@ -86,7 +84,6 @@ static MergeJoin *make_mergejoin(List *tlist,
 								 Plan *lefttree, Plan *righttree,
 								 JoinType jointype);
 static void copy_path_costsize(Plan *dest, Path *src);
-static void copy_plan_costsize(Plan *dest, Plan *src);
 
 /*
  * create_plan
@@ -1109,7 +1106,7 @@ copy_path_costsize(Plan *dest, Path *src)
  * but it helps produce more reasonable-looking EXPLAIN output.
  * (Some callers alter the info after copying it.)
  */
-static void
+void
 copy_plan_costsize(Plan *dest, Plan *src)
 {
 	if (src)
@@ -1206,7 +1203,7 @@ make_tidscan(List *qptlist,
 	return node;
 }
 
-static SubqueryScan *
+SubqueryScan *
 make_subqueryscan(List *qptlist,
 				  List *qpqual,
 				  Index scanrelid,
@@ -1593,6 +1590,67 @@ make_unique(List *tlist, Plan *lefttree, List *distinctList)
 	return node;
 }
 
+/*
+ * distinctList is a list of SortClauses, identifying the targetlist items
+ * that should be considered by the SetOp filter.
+ */
+
+SetOp *
+make_setop(SetOpCmd cmd, List *tlist, Plan *lefttree,
+		   List *distinctList, AttrNumber flagColIdx)
+{
+	SetOp	   *node = makeNode(SetOp);
+	Plan	   *plan = &node->plan;
+	int			numCols = length(distinctList);
+	int			keyno = 0;
+	AttrNumber *dupColIdx;
+	List	   *slitem;
+
+	copy_plan_costsize(plan, lefttree);
+
+	/*
+	 * Charge one cpu_operator_cost per comparison per input tuple. We
+	 * assume all columns get compared at most of the tuples.
+	 */
+	plan->total_cost += cpu_operator_cost * plan->plan_rows * numCols;
+
+	/*
+	 * As for Group, we make the unsupported assumption that there will be
+	 * 10% as many tuples out as in.
+	 */
+	plan->plan_rows *= 0.1;
+	if (plan->plan_rows < 1)
+		plan->plan_rows = 1;
+
+	plan->state = (EState *) NULL;
+	plan->targetlist = tlist;
+	plan->qual = NIL;
+	plan->lefttree = lefttree;
+	plan->righttree = NULL;
+
+	/*
+	 * convert SortClause list into array of attr indexes, as wanted by
+	 * exec
+	 */
+	Assert(numCols > 0);
+	dupColIdx = (AttrNumber *) palloc(sizeof(AttrNumber) * numCols);
+
+	foreach(slitem, distinctList)
+	{
+		SortClause *sortcl = (SortClause *) lfirst(slitem);
+		TargetEntry *tle = get_sortgroupclause_tle(sortcl, tlist);
+
+		dupColIdx[keyno++] = tle->resdom->resno;
+	}
+
+	node->cmd = cmd;
+	node->numCols = numCols;
+	node->dupColIdx = dupColIdx;
+	node->flagColIdx = flagColIdx;
+
+	return node;
+}
+
 Result *
 make_result(List *tlist,
 			Node *resconstantqual,
diff --git a/src/backend/optimizer/plan/planmain.c b/src/backend/optimizer/plan/planmain.c
index 29cfccfef7b..a9747b32799 100644
--- a/src/backend/optimizer/plan/planmain.c
+++ b/src/backend/optimizer/plan/planmain.c
@@ -14,7 +14,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/optimizer/plan/planmain.c,v 1.60 2000/09/29 18:21:33 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/optimizer/plan/planmain.c,v 1.61 2000/10/05 19:11:29 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -174,8 +174,6 @@ subplanner(Query *root,
 	List	   *brel;
 	RelOptInfo *final_rel;
 	Plan	   *resultplan;
-	MemoryContext mycontext;
-	MemoryContext oldcxt;
 	Path	   *cheapestpath;
 	Path	   *presortedpath;
 
@@ -228,24 +226,6 @@ subplanner(Query *root,
 	root->query_pathkeys = canonicalize_pathkeys(root, root->query_pathkeys);
 
 	/*
-	 * We might allocate quite a lot of storage during planning (due to
-	 * constructing lots of Paths), but all of it can be reclaimed after
-	 * we generate the finished Plan tree.  Work in a temporary context
-	 * to let that happen.  We make the context a child of
-	 * TransactionCommandContext so it will be freed if error abort.
-	 *
-	 * Note: beware of trying to move this up to the start of this routine.
-	 * Some of the data structures built above --- notably the pathkey
-	 * equivalence sets --- will still be needed after this routine exits.
-	 */
-	mycontext = AllocSetContextCreate(TransactionCommandContext,
-									  "Planner",
-									  ALLOCSET_DEFAULT_MINSIZE,
-									  ALLOCSET_DEFAULT_INITSIZE,
-									  ALLOCSET_DEFAULT_MAXSIZE);
-	oldcxt = MemoryContextSwitchTo(mycontext);
-
-	/*
 	 * Ready to do the primary planning.
 	 */
 	final_rel = make_one_rel(root);
@@ -355,25 +335,5 @@ subplanner(Query *root,
 
 plan_built:
 
-	/*
-	 * Must copy the completed plan tree and its pathkeys out of temporary
-	 * context.  We also have to copy the rtable in case it contains any
-	 * subqueries.  (If it does, they'll have been modified during the
-	 * recursive invocation of planner.c, and hence will contain substructure
-	 * allocated in my temporary context...)
-	 */
-	MemoryContextSwitchTo(oldcxt);
-
-	resultplan = copyObject(resultplan);
-
-	root->query_pathkeys = copyObject(root->query_pathkeys);
-
-	root->rtable = copyObject(root->rtable);
-
-	/*
-	 * Now we can release the Path storage.
-	 */
-	MemoryContextDelete(mycontext);
-
 	return resultplan;
 }
diff --git a/src/backend/optimizer/plan/planner.c b/src/backend/optimizer/plan/planner.c
index 937628121b3..d73ca9a34ac 100644
--- a/src/backend/optimizer/plan/planner.c
+++ b/src/backend/optimizer/plan/planner.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/optimizer/plan/planner.c,v 1.91 2000/09/29 18:21:33 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/optimizer/plan/planner.c,v 1.92 2000/10/05 19:11:29 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -48,7 +48,6 @@ static List *make_subplanTargetList(Query *parse, List *tlist,
 static Plan *make_groupplan(List *group_tlist, bool tuplePerGroup,
 			   List *groupClause, AttrNumber *grpColIdx,
 			   bool is_presorted, Plan *subplan);
-static Plan *make_sortplan(List *tlist, Plan *plannode, List *sortcls);
 
 /*****************************************************************************
  *
@@ -60,43 +59,32 @@ planner(Query *parse)
 {
 	Plan	   *result_plan;
 	Index		save_PlannerQueryLevel;
-	List	   *save_PlannerInitPlan;
 	List	   *save_PlannerParamVar;
-	int			save_PlannerPlanId;
 
 	/*
-	 * The outer planner can be called recursively, for example to process
-	 * a subquery in the rangetable.  (A less obvious example occurs when
-	 * eval_const_expressions tries to simplify an SQL function.)
-	 * So, global state variables must be saved and restored.
+	 * The planner can be called recursively (an example is when
+	 * eval_const_expressions tries to simplify an SQL function).
+	 * So, these global state variables must be saved and restored.
 	 *
-	 * (Perhaps these should be moved into the Query structure instead?)
+	 * These vars cannot be moved into the Query structure since their
+	 * whole purpose is communication across multiple sub-Queries.
+	 *
+	 * Note we do NOT save and restore PlannerPlanId: it exists to assign
+	 * unique IDs to SubPlan nodes, and we want those IDs to be unique
+	 * for the life of a backend.  Also, PlannerInitPlan is saved/restored
+	 * in subquery_planner, not here.
 	 */
 	save_PlannerQueryLevel = PlannerQueryLevel;
-	save_PlannerInitPlan = PlannerInitPlan;
 	save_PlannerParamVar = PlannerParamVar;
-	save_PlannerPlanId = PlannerPlanId;
 
-	/* Initialize state for subselects */
-	PlannerQueryLevel = 1;
-	PlannerInitPlan = NULL;
-	PlannerParamVar = NULL;
-	PlannerPlanId = 0;
+	/* Initialize state for handling outer-level references and params */
+	PlannerQueryLevel = 0;		/* will be 1 in top-level subquery_planner */
+	PlannerParamVar = NIL;
 
-	/* this should go away sometime soon */
-	transformKeySetQuery(parse);
-
-	/* primary planning entry point (may recurse for sublinks) */
+	/* primary planning entry point (may recurse for subqueries) */
 	result_plan = subquery_planner(parse, -1.0 /* default case */ );
 
-	Assert(PlannerQueryLevel == 1);
-
-	/* if top-level query had subqueries, do housekeeping for them */
-	if (PlannerPlanId > 0)
-	{
-		(void) SS_finalize_plan(result_plan);
-		result_plan->initPlan = PlannerInitPlan;
-	}
+	Assert(PlannerQueryLevel == 0);
 
 	/* executor wants to know total number of Params used overall */
 	result_plan->nParamExec = length(PlannerParamVar);
@@ -106,9 +94,7 @@ planner(Query *parse)
 
 	/* restore state for outer planner, if any */
 	PlannerQueryLevel = save_PlannerQueryLevel;
-	PlannerInitPlan = save_PlannerInitPlan;
 	PlannerParamVar = save_PlannerParamVar;
-	PlannerPlanId = save_PlannerPlanId;
 
 	return result_plan;
 }
@@ -125,14 +111,9 @@ planner(Query *parse)
  *
  * Basically, this routine does the stuff that should only be done once
  * per Query object.  It then calls union_planner, which may be called
- * recursively on the same Query node in order to handle UNIONs and/or
- * inheritance.  subquery_planner is called recursively from subselect.c
- * to handle sub-Query nodes found within the query's expressions.
- *
- * prepunion.c uses an unholy combination of calling union_planner when
- * recursing on the primary Query node, or subquery_planner when recursing
- * on a UNION'd Query node that hasn't previously been seen by
- * subquery_planner.  That whole chunk of code needs rewritten from scratch.
+ * recursively on the same Query node in order to handle inheritance.
+ * subquery_planner will be called recursively to handle sub-Query nodes
+ * found within the query's expressions and rangetable.
  *
  * Returns a query plan.
  *--------------------
@@ -140,6 +121,20 @@ planner(Query *parse)
 Plan *
 subquery_planner(Query *parse, double tuple_fraction)
 {
+	List	   *saved_initplan = PlannerInitPlan;
+	int			saved_planid = PlannerPlanId;
+	Plan	   *plan;
+	List	   *lst;
+
+	/* Set up for a new level of subquery */
+	PlannerQueryLevel++;
+	PlannerInitPlan = NIL;
+
+#ifdef ENABLE_KEY_SET_QUERY
+	/* this should go away sometime soon */
+	transformKeySetQuery(parse);
+#endif
+
 	/*
 	 * Check to see if any subqueries in the rangetable can be merged into
 	 * this query.
@@ -179,9 +174,9 @@ subquery_planner(Query *parse, double tuple_fraction)
 											  EXPRKIND_HAVING);
 
 	/*
-	 * Do the main planning (potentially recursive)
+	 * Do the main planning (potentially recursive for inheritance)
 	 */
-	return union_planner(parse, tuple_fraction);
+	plan = union_planner(parse, tuple_fraction);
 
 	/*
 	 * XXX should any more of union_planner's activity be moved here?
@@ -190,6 +185,35 @@ subquery_planner(Query *parse, double tuple_fraction)
 	 * but I suspect it would pay off in simplicity and avoidance of
 	 * wasted cycles.
 	 */
+
+	/*
+	 * If any subplans were generated, or if we're inside a subplan,
+	 * build subPlan, extParam and locParam lists for plan nodes.
+	 */
+	if (PlannerPlanId != saved_planid || PlannerQueryLevel > 1)
+	{
+		(void) SS_finalize_plan(plan);
+		/*
+		 * At the moment, SS_finalize_plan doesn't handle initPlans
+		 * and so we assign them to the topmost plan node.
+		 */
+		plan->initPlan = PlannerInitPlan;
+		/* Must add the initPlans' extParams to the topmost node's, too */
+		foreach(lst, plan->initPlan)
+		{
+			SubPlan *subplan = (SubPlan *) lfirst(lst);
+
+			plan->extParam = set_unioni(plan->extParam,
+										subplan->plan->extParam);
+		}
+	}
+
+	/* Return to outer subquery context */
+	PlannerQueryLevel--;
+	PlannerInitPlan = saved_initplan;
+	/* we do NOT restore PlannerPlanId; that's not an oversight! */
+
+	return plan;
 }
 
 /*
@@ -320,9 +344,10 @@ is_simple_subquery(Query *subquery)
 	if (subquery->limitOffset || subquery->limitCount)
 		elog(ERROR, "LIMIT is not supported in subselects");
 	/*
-	 * Can't currently pull up a union query.  Maybe after querytree redesign.
+	 * Can't currently pull up a query with setops.
+	 * Maybe after querytree redesign...
 	 */
-	if (subquery->unionClause)
+	if (subquery->setOperations)
 		return false;
 	/*
 	 * Can't pull up a subquery involving grouping, aggregation, or sorting.
@@ -573,7 +598,7 @@ preprocess_qual_conditions(Query *parse, Node *jtnode)
 
 /*--------------------
  * union_planner
- *	  Invokes the planner on union-type queries (both regular UNIONs and
+ *	  Invokes the planner on union-type queries (both set operations and
  *	  appends produced by inheritance), recursing if necessary to get them
  *	  all, then processes normal plans.
  *
@@ -606,24 +631,31 @@ union_planner(Query *parse,
 	Index		rt_index;
 	List	   *inheritors;
 
-	if (parse->unionClause)
+	if (parse->setOperations)
 	{
-		result_plan = plan_union_queries(parse);
-		/* XXX do we need to do this? bjm 12/19/97 */
-		tlist = preprocess_targetlist(tlist,
-									  parse->commandType,
-									  parse->resultRelation,
-									  parse->rtable);
+		/*
+		 * Construct the plan for set operations.  The result will
+		 * not need any work except perhaps a top-level sort.
+		 */
+		result_plan = plan_set_operations(parse);
+
+		/*
+		 * We should not need to call preprocess_targetlist, since we must
+		 * be in a SELECT query node.
+		 */
+		Assert(parse->commandType == CMD_SELECT);
 
 		/*
 		 * We leave current_pathkeys NIL indicating we do not know sort
-		 * order.  This is correct for the appended-together subplan
-		 * results, even if the subplans themselves produced sorted results.
+		 * order.  This is correct when the top set operation is UNION ALL,
+		 * since the appended-together results are unsorted even if the
+		 * subplans were sorted.  For other set operations we could be
+		 * smarter --- future improvement!
 		 */
 
 		/*
 		 * Calculate pathkeys that represent grouping/ordering
-		 * requirements
+		 * requirements (grouping should always be null, but...)
 		 */
 		group_pathkeys = make_pathkeys_for_sortclauses(parse->groupClause,
 													   tlist);
@@ -886,7 +918,7 @@ union_planner(Query *parse,
 				tuple_fraction = 0.25;
 		}
 
-		/* Generate the (sub) plan */
+		/* Generate the basic plan for this Query */
 		result_plan = query_planner(parse,
 									sub_tlist,
 									tuple_fraction);
@@ -1176,7 +1208,7 @@ make_groupplan(List *group_tlist,
  * make_sortplan
  *	  Add a Sort node to implement an explicit ORDER BY clause.
  */
-static Plan *
+Plan *
 make_sortplan(List *tlist, Plan *plannode, List *sortcls)
 {
 	List	   *sort_tlist;
diff --git a/src/backend/optimizer/plan/setrefs.c b/src/backend/optimizer/plan/setrefs.c
index ad1b47aaeb6..14c9dad3ef3 100644
--- a/src/backend/optimizer/plan/setrefs.c
+++ b/src/backend/optimizer/plan/setrefs.c
@@ -9,7 +9,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/optimizer/plan/setrefs.c,v 1.66 2000/09/29 18:21:33 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/optimizer/plan/setrefs.c,v 1.67 2000/10/05 19:11:29 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -103,9 +103,15 @@ set_plan_references(Plan *plan)
 			fix_expr_references(plan, (Node *) plan->qual);
 			break;
 		case T_SubqueryScan:
+			/*
+			 * We do not do set_uppernode_references() here, because
+			 * a SubqueryScan will always have been created with correct
+			 * references to its subplan's outputs to begin with.
+			 */
 			fix_expr_references(plan, (Node *) plan->targetlist);
 			fix_expr_references(plan, (Node *) plan->qual);
-			/* No need to recurse into the subplan, it's fixed already */
+			/* Recurse into subplan too */
+			set_plan_references(((SubqueryScan *) plan)->subplan);
 			break;
 		case T_NestLoop:
 			set_join_references((Join *) plan);
@@ -132,6 +138,7 @@ set_plan_references(Plan *plan)
 		case T_Material:
 		case T_Sort:
 		case T_Unique:
+		case T_SetOp:
 		case T_Hash:
 
 			/*
@@ -170,6 +177,7 @@ set_plan_references(Plan *plan)
 			 * Append, like Sort et al, doesn't actually evaluate its
 			 * targetlist or quals, and we haven't bothered to give it
 			 * its own tlist copy.  So, don't fix targetlist/qual.
+			 * But do recurse into subplans.
 			 */
 			foreach(pl, ((Append *) plan)->appendplans)
 				set_plan_references((Plan *) lfirst(pl));
diff --git a/src/backend/optimizer/plan/subselect.c b/src/backend/optimizer/plan/subselect.c
index 182d1384aa1..03e38371df5 100644
--- a/src/backend/optimizer/plan/subselect.c
+++ b/src/backend/optimizer/plan/subselect.c
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/optimizer/plan/subselect.c,v 1.42 2000/09/29 18:21:33 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/optimizer/plan/subselect.c,v 1.43 2000/10/05 19:11:29 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -29,7 +29,8 @@
 Index		PlannerQueryLevel;	/* level of current query */
 List	   *PlannerInitPlan;	/* init subplans for current query */
 List	   *PlannerParamVar;	/* to get Var from Param->paramid */
-int			PlannerPlanId;		/* to assign unique ID to subquery plans */
+
+int			PlannerPlanId = 0;	/* to assign unique ID to subquery plans */
 
 /*--------------------
  * PlannerParamVar is a list of Var nodes, wherein the n'th entry
@@ -81,7 +82,7 @@ replace_var(Var *var)
 
 	/*
 	 * If there's already a PlannerParamVar entry for this same Var, just
-	 * use it.	NOTE: in situations involving UNION or inheritance, it is
+	 * use it.	NOTE: in sufficiently complex querytrees, it is
 	 * possible for the same varno/varlevel to refer to different RTEs in
 	 * different parts of the parsetree, so that different fields might
 	 * end up sharing the same Param number.  As long as we check the
@@ -128,11 +129,6 @@ make_subplan(SubLink *slink)
 	Plan	   *plan;
 	List	   *lst;
 	Node	   *result;
-	List	   *saved_ip = PlannerInitPlan;
-
-	PlannerInitPlan = NULL;
-
-	PlannerQueryLevel++;		/* we become child */
 
 	/*
 	 * Check to see if this node was already processed; if so we have
@@ -181,45 +177,30 @@ make_subplan(SubLink *slink)
 	else
 		tuple_fraction = -1.0;	/* default behavior */
 
-	node->plan = plan = subquery_planner(subquery, tuple_fraction);
-
 	/*
-	 * Assign subPlan, extParam and locParam to plan nodes. At the moment,
-	 * SS_finalize_plan doesn't handle initPlan-s and so we assign them to
-	 * the topmost plan node and take care about its extParam too.
+	 * Generate the plan for the subquery.
 	 */
-	(void) SS_finalize_plan(plan);
-	plan->initPlan = PlannerInitPlan;
-
-	/* Create extParam list as union of InitPlan-s' lists */
-	foreach(lst, PlannerInitPlan)
-	{
-		List	   *lp;
-
-		foreach(lp, ((SubPlan *) lfirst(lst))->plan->extParam)
-		{
-			if (!intMember(lfirsti(lp), plan->extParam))
-				plan->extParam = lappendi(plan->extParam, lfirsti(lp));
-		}
-	}
+	node->plan = plan = subquery_planner(subquery, tuple_fraction);
 
-	/* and now we are parent again */
-	PlannerInitPlan = saved_ip;
-	PlannerQueryLevel--;
+	node->plan_id = PlannerPlanId++; /* Assign unique ID to this SubPlan */
 
-	node->plan_id = PlannerPlanId++;
 	node->rtable = subquery->rtable;
 	node->sublink = slink;
+
 	slink->subselect = NULL;	/* cool ?! see error check above! */
 
-	/* make parParam list of params coming from current query level */
+	/*
+	 * Make parParam list of params that current query level will pass
+	 * to this child plan.
+	 */
 	foreach(lst, plan->extParam)
 	{
-		Var		   *var = nth(lfirsti(lst), PlannerParamVar);
+		int			paramid = lfirsti(lst);
+		Var		   *var = nth(paramid, PlannerParamVar);
 
 		/* note varlevelsup is absolute level number */
 		if (var->varlevelsup == PlannerQueryLevel)
-			node->parParam = lappendi(node->parParam, lfirsti(lst));
+			node->parParam = lappendi(node->parParam, paramid);
 	}
 
 	/*
@@ -625,6 +606,11 @@ SS_finalize_plan(Plan *plan)
 								 SS_finalize_plan((Plan *) lfirst(lst)));
 			break;
 
+		case T_SubqueryScan:
+			results.paramids = set_unioni(results.paramids,
+						SS_finalize_plan(((SubqueryScan *) plan)->subplan));
+			break;
+
 		case T_IndexScan:
 			finalize_primnode((Node *) ((IndexScan *) plan)->indxqual,
 							  &results);
@@ -667,10 +653,10 @@ SS_finalize_plan(Plan *plan)
 
 		case T_Agg:
 		case T_SeqScan:
-		case T_SubqueryScan:
 		case T_Material:
 		case T_Sort:
 		case T_Unique:
+		case T_SetOp:
 		case T_Group:
 			break;
 
@@ -689,17 +675,18 @@ SS_finalize_plan(Plan *plan)
 
 	foreach(lst, results.paramids)
 	{
-		Var		   *var = nth(lfirsti(lst), PlannerParamVar);
+		int			paramid = lfirsti(lst);
+		Var		   *var = nth(paramid, PlannerParamVar);
 
 		/* note varlevelsup is absolute level number */
 		if (var->varlevelsup < PlannerQueryLevel)
-			extParam = lappendi(extParam, lfirsti(lst));
+			extParam = lappendi(extParam, paramid);
 		else if (var->varlevelsup > PlannerQueryLevel)
 			elog(ERROR, "SS_finalize_plan: plan shouldn't reference subplan's variable");
 		else
 		{
 			Assert(var->varno == 0 && var->varattno == 0);
-			locParam = lappendi(locParam, lfirsti(lst));
+			locParam = lappendi(locParam, paramid);
 		}
 	}