Adding upstream version 14.5.upstream/14.5upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 3178 insertions, 0 deletions

diff --git a/src/backend/optimizer/plan/setrefs.c b/src/backend/optimizer/plan/setrefs.c
new file mode 100644
index 0000000..c79a65e
--- /dev/null
+++ b/src/backend/optimizer/plan/setrefs.c
@@ -0,0 +1,3178 @@
+/*-------------------------------------------------------------------------
+ *
+ * setrefs.c
+ *	  Post-processing of a completed plan tree: fix references to subplan
+ *	  vars, compute regproc values for operators, etc
+ *
+ * Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ *
+ * IDENTIFICATION
+ *	  src/backend/optimizer/plan/setrefs.c
+ *
+ *-------------------------------------------------------------------------
+ */
+#include "postgres.h"
+
+#include "access/transam.h"
+#include "catalog/pg_type.h"
+#include "nodes/makefuncs.h"
+#include "nodes/nodeFuncs.h"
+#include "optimizer/optimizer.h"
+#include "optimizer/pathnode.h"
+#include "optimizer/planmain.h"
+#include "optimizer/planner.h"
+#include "optimizer/tlist.h"
+#include "tcop/utility.h"
+#include "utils/lsyscache.h"
+#include "utils/syscache.h"
+
+
+typedef struct
+{
+	Index		varno;			/* RT index of Var */
+	AttrNumber	varattno;		/* attr number of Var */
+	AttrNumber	resno;			/* TLE position of Var */
+} tlist_vinfo;
+
+typedef struct
+{
+	List	   *tlist;			/* underlying target list */
+	int			num_vars;		/* number of plain Var tlist entries */
+	bool		has_ph_vars;	/* are there PlaceHolderVar entries? */
+	bool		has_non_vars;	/* are there other entries? */
+	tlist_vinfo vars[FLEXIBLE_ARRAY_MEMBER];	/* has num_vars entries */
+} indexed_tlist;
+
+typedef struct
+{
+	PlannerInfo *root;
+	int			rtoffset;
+	double		num_exec;
+} fix_scan_expr_context;
+
+typedef struct
+{
+	PlannerInfo *root;
+	indexed_tlist *outer_itlist;
+	indexed_tlist *inner_itlist;
+	Index		acceptable_rel;
+	int			rtoffset;
+	double		num_exec;
+} fix_join_expr_context;
+
+typedef struct
+{
+	PlannerInfo *root;
+	indexed_tlist *subplan_itlist;
+	Index		newvarno;
+	int			rtoffset;
+	double		num_exec;
+} fix_upper_expr_context;
+
+/*
+ * Selecting the best alternative in an AlternativeSubPlan expression requires
+ * estimating how many times that expression will be evaluated.  For an
+ * expression in a plan node's targetlist, the plan's estimated number of
+ * output rows is clearly what to use, but for an expression in a qual it's
+ * far less clear.  Since AlternativeSubPlans aren't heavily used, we don't
+ * want to expend a lot of cycles making such estimates.  What we use is twice
+ * the number of output rows.  That's not entirely unfounded: we know that
+ * clause_selectivity() would fall back to a default selectivity estimate
+ * of 0.5 for any SubPlan, so if the qual containing the SubPlan is the last
+ * to be applied (which it likely would be, thanks to order_qual_clauses()),
+ * this matches what we could have estimated in a far more laborious fashion.
+ * Obviously there are many other scenarios, but it's probably not worth the
+ * trouble to try to improve on this estimate, especially not when we don't
+ * have a better estimate for the selectivity of the SubPlan qual itself.
+ */
+#define NUM_EXEC_TLIST(parentplan)  ((parentplan)->plan_rows)
+#define NUM_EXEC_QUAL(parentplan)   ((parentplan)->plan_rows * 2.0)
+
+/*
+ * Check if a Const node is a regclass value.  We accept plain OID too,
+ * since a regclass Const will get folded to that type if it's an argument
+ * to oideq or similar operators.  (This might result in some extraneous
+ * values in a plan's list of relation dependencies, but the worst result
+ * would be occasional useless replans.)
+ */
+#define ISREGCLASSCONST(con) \
+	(((con)->consttype == REGCLASSOID || (con)->consttype == OIDOID) && \
+	 !(con)->constisnull)
+
+#define fix_scan_list(root, lst, rtoffset, num_exec) \
+	((List *) fix_scan_expr(root, (Node *) (lst), rtoffset, num_exec))
+
+static void add_rtes_to_flat_rtable(PlannerInfo *root, bool recursing);
+static void flatten_unplanned_rtes(PlannerGlobal *glob, RangeTblEntry *rte);
+static bool flatten_rtes_walker(Node *node, PlannerGlobal *glob);
+static void add_rte_to_flat_rtable(PlannerGlobal *glob, RangeTblEntry *rte);
+static Plan *set_plan_refs(PlannerInfo *root, Plan *plan, int rtoffset);
+static Plan *set_indexonlyscan_references(PlannerInfo *root,
+										  IndexOnlyScan *plan,
+										  int rtoffset);
+static Plan *set_subqueryscan_references(PlannerInfo *root,
+										 SubqueryScan *plan,
+										 int rtoffset);
+static bool trivial_subqueryscan(SubqueryScan *plan);
+static Plan *clean_up_removed_plan_level(Plan *parent, Plan *child);
+static void set_foreignscan_references(PlannerInfo *root,
+									   ForeignScan *fscan,
+									   int rtoffset);
+static void set_customscan_references(PlannerInfo *root,
+									  CustomScan *cscan,
+									  int rtoffset);
+static Plan *set_append_references(PlannerInfo *root,
+								   Append *aplan,
+								   int rtoffset);
+static Plan *set_mergeappend_references(PlannerInfo *root,
+										MergeAppend *mplan,
+										int rtoffset);
+static void set_hash_references(PlannerInfo *root, Plan *plan, int rtoffset);
+static Relids offset_relid_set(Relids relids, int rtoffset);
+static Node *fix_scan_expr(PlannerInfo *root, Node *node,
+						   int rtoffset, double num_exec);
+static Node *fix_scan_expr_mutator(Node *node, fix_scan_expr_context *context);
+static bool fix_scan_expr_walker(Node *node, fix_scan_expr_context *context);
+static void set_join_references(PlannerInfo *root, Join *join, int rtoffset);
+static void set_upper_references(PlannerInfo *root, Plan *plan, int rtoffset);
+static void set_param_references(PlannerInfo *root, Plan *plan);
+static Node *convert_combining_aggrefs(Node *node, void *context);
+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 rtoffset);
+static Var *search_indexed_tlist_for_non_var(Expr *node,
+											 indexed_tlist *itlist,
+											 Index newvarno);
+static Var *search_indexed_tlist_for_sortgroupref(Expr *node,
+												  Index sortgroupref,
+												  indexed_tlist *itlist,
+												  Index newvarno);
+static List *fix_join_expr(PlannerInfo *root,
+						   List *clauses,
+						   indexed_tlist *outer_itlist,
+						   indexed_tlist *inner_itlist,
+						   Index acceptable_rel,
+						   int rtoffset, double num_exec);
+static Node *fix_join_expr_mutator(Node *node,
+								   fix_join_expr_context *context);
+static Node *fix_upper_expr(PlannerInfo *root,
+							Node *node,
+							indexed_tlist *subplan_itlist,
+							Index newvarno,
+							int rtoffset, double num_exec);
+static Node *fix_upper_expr_mutator(Node *node,
+									fix_upper_expr_context *context);
+static List *set_returning_clause_references(PlannerInfo *root,
+											 List *rlist,
+											 Plan *topplan,
+											 Index resultRelation,
+											 int rtoffset);
+
+
+/*****************************************************************************
+ *
+ *		SUBPLAN REFERENCES
+ *
+ *****************************************************************************/
+
+/*
+ * set_plan_references
+ *
+ * This is the final processing pass of the planner/optimizer.  The plan
+ * tree is complete; we just have to adjust some representational details
+ * for the convenience of the executor:
+ *
+ * 1. We flatten the various subquery rangetables into a single list, and
+ * zero out RangeTblEntry fields that are not useful to the executor.
+ *
+ * 2. We adjust Vars in scan nodes to be consistent with the flat rangetable.
+ *
+ * 3. We adjust Vars in upper plan nodes to refer to the outputs of their
+ * subplans.
+ *
+ * 4. Aggrefs in Agg plan nodes need to be adjusted in some cases involving
+ * partial aggregation or minmax aggregate optimization.
+ *
+ * 5. PARAM_MULTIEXPR Params are replaced by regular PARAM_EXEC Params,
+ * now that we have finished planning all MULTIEXPR subplans.
+ *
+ * 6. AlternativeSubPlan expressions are replaced by just one of their
+ * alternatives, using an estimate of how many times they'll be executed.
+ *
+ * 7. We compute regproc OIDs for operators (ie, we look up the function
+ * that implements each op).
+ *
+ * 8. We create lists of specific objects that the plan depends on.
+ * This will be used by plancache.c to drive invalidation of cached plans.
+ * Relation dependencies are represented by OIDs, and everything else by
+ * PlanInvalItems (this distinction is motivated by the shared-inval APIs).
+ * Currently, relations, user-defined functions, and domains are the only
+ * types of objects that are explicitly tracked this way.
+ *
+ * 9. We assign every plan node in the tree a unique ID.
+ *
+ * We also perform one final optimization step, which is to delete
+ * SubqueryScan, Append, and MergeAppend plan nodes that aren't doing
+ * anything useful.  The reason for doing this last is that
+ * it can't readily be done before set_plan_references, because it would
+ * break set_upper_references: the Vars in the child plan's top tlist
+ * wouldn't match up with the Vars in the outer plan tree.  A SubqueryScan
+ * serves a necessary function as a buffer between outer query and subquery
+ * variable numbering ... but after we've flattened the rangetable this is
+ * no longer a problem, since then there's only one rtindex namespace.
+ * Likewise, Append and MergeAppend buffer between the parent and child vars
+ * of an appendrel, but we don't need to worry about that once we've done
+ * set_plan_references.
+ *
+ * set_plan_references recursively traverses the whole plan tree.
+ *
+ * The return value is normally the same Plan node passed in, but can be
+ * different when the passed-in Plan is a node we decide isn't needed.
+ *
+ * The flattened rangetable entries are appended to root->glob->finalrtable.
+ * Also, rowmarks entries are appended to root->glob->finalrowmarks, and the
+ * RT indexes of ModifyTable result relations to root->glob->resultRelations,
+ * and flattened AppendRelInfos are appended to root->glob->appendRelations.
+ * Plan dependencies are appended to root->glob->relationOids (for relations)
+ * and root->glob->invalItems (for everything else).
+ *
+ * Notice that we modify Plan nodes in-place, but use expression_tree_mutator
+ * to process targetlist and qual expressions.  We can assume that the Plan
+ * nodes were just built by the planner and are not multiply referenced, but
+ * it's not so safe to assume that for expression tree nodes.
+ */
+Plan *
+set_plan_references(PlannerInfo *root, Plan *plan)
+{
+	Plan	   *result;
+	PlannerGlobal *glob = root->glob;
+	int			rtoffset = list_length(glob->finalrtable);
+	ListCell   *lc;
+
+	/*
+	 * Add all the query's RTEs to the flattened rangetable.  The live ones
+	 * will have their rangetable indexes increased by rtoffset.  (Additional
+	 * RTEs, not referenced by the Plan tree, might get added after those.)
+	 */
+	add_rtes_to_flat_rtable(root, false);
+
+	/*
+	 * Adjust RT indexes of PlanRowMarks and add to final rowmarks list
+	 */
+	foreach(lc, root->rowMarks)
+	{
+		PlanRowMark *rc = lfirst_node(PlanRowMark, lc);
+		PlanRowMark *newrc;
+
+		/* flat copy is enough since all fields are scalars */
+		newrc = (PlanRowMark *) palloc(sizeof(PlanRowMark));
+		memcpy(newrc, rc, sizeof(PlanRowMark));
+
+		/* adjust indexes ... but *not* the rowmarkId */
+		newrc->rti += rtoffset;
+		newrc->prti += rtoffset;
+
+		glob->finalrowmarks = lappend(glob->finalrowmarks, newrc);
+	}
+
+	/*
+	 * Adjust RT indexes of AppendRelInfos and add to final appendrels list.
+	 * We assume the AppendRelInfos were built during planning and don't need
+	 * to be copied.
+	 */
+	foreach(lc, root->append_rel_list)
+	{
+		AppendRelInfo *appinfo = lfirst_node(AppendRelInfo, lc);
+
+		/* adjust RT indexes */
+		appinfo->parent_relid += rtoffset;
+		appinfo->child_relid += rtoffset;
+
+		/*
+		 * Rather than adjust the translated_vars entries, just drop 'em.
+		 * Neither the executor nor EXPLAIN currently need that data.
+		 */
+		appinfo->translated_vars = NIL;
+
+		glob->appendRelations = lappend(glob->appendRelations, appinfo);
+	}
+
+	/* If needed, create workspace for processing AlternativeSubPlans */
+	if (root->hasAlternativeSubPlans)
+	{
+		root->isAltSubplan = (bool *)
+			palloc0(list_length(glob->subplans) * sizeof(bool));
+		root->isUsedSubplan = (bool *)
+			palloc0(list_length(glob->subplans) * sizeof(bool));
+	}
+
+	/* Now fix the Plan tree */
+	result = set_plan_refs(root, plan, rtoffset);
+
+	/*
+	 * If we have AlternativeSubPlans, it is likely that we now have some
+	 * unreferenced subplans in glob->subplans.  To avoid expending cycles on
+	 * those subplans later, get rid of them by setting those list entries to
+	 * NULL.  (Note: we can't do this immediately upon processing an
+	 * AlternativeSubPlan, because there may be multiple copies of the
+	 * AlternativeSubPlan, and they can get resolved differently.)
+	 */
+	if (root->hasAlternativeSubPlans)
+	{
+		foreach(lc, glob->subplans)
+		{
+			int			ndx = foreach_current_index(lc);
+
+			/*
+			 * If it was used by some AlternativeSubPlan in this query level,
+			 * but wasn't selected as best by any AlternativeSubPlan, then we
+			 * don't need it.  Do not touch subplans that aren't parts of
+			 * AlternativeSubPlans.
+			 */
+			if (root->isAltSubplan[ndx] && !root->isUsedSubplan[ndx])
+				lfirst(lc) = NULL;
+		}
+	}
+
+	return result;
+}
+
+/*
+ * Extract RangeTblEntries from the plan's rangetable, and add to flat rtable
+ *
+ * This can recurse into subquery plans; "recursing" is true if so.
+ */
+static void
+add_rtes_to_flat_rtable(PlannerInfo *root, bool recursing)
+{
+	PlannerGlobal *glob = root->glob;
+	Index		rti;
+	ListCell   *lc;
+
+	/*
+	 * Add the query's own RTEs to the flattened rangetable.
+	 *
+	 * At top level, we must add all RTEs so that their indexes in the
+	 * flattened rangetable match up with their original indexes.  When
+	 * recursing, we only care about extracting relation RTEs.
+	 */
+	foreach(lc, root->parse->rtable)
+	{
+		RangeTblEntry *rte = (RangeTblEntry *) lfirst(lc);
+
+		if (!recursing || rte->rtekind == RTE_RELATION)
+			add_rte_to_flat_rtable(glob, rte);
+	}
+
+	/*
+	 * If there are any dead subqueries, they are not referenced in the Plan
+	 * tree, so we must add RTEs contained in them to the flattened rtable
+	 * separately.  (If we failed to do this, the executor would not perform
+	 * expected permission checks for tables mentioned in such subqueries.)
+	 *
+	 * Note: this pass over the rangetable can't be combined with the previous
+	 * one, because that would mess up the numbering of the live RTEs in the
+	 * flattened rangetable.
+	 */
+	rti = 1;
+	foreach(lc, root->parse->rtable)
+	{
+		RangeTblEntry *rte = (RangeTblEntry *) lfirst(lc);
+
+		/*
+		 * We should ignore inheritance-parent RTEs: their contents have been
+		 * pulled up into our rangetable already.  Also ignore any subquery
+		 * RTEs without matching RelOptInfos, as they likewise have been
+		 * pulled up.
+		 */
+		if (rte->rtekind == RTE_SUBQUERY && !rte->inh &&
+			rti < root->simple_rel_array_size)
+		{
+			RelOptInfo *rel = root->simple_rel_array[rti];
+
+			if (rel != NULL)
+			{
+				Assert(rel->relid == rti);	/* sanity check on array */
+
+				/*
+				 * The subquery might never have been planned at all, if it
+				 * was excluded on the basis of self-contradictory constraints
+				 * in our query level.  In this case apply
+				 * flatten_unplanned_rtes.
+				 *
+				 * If it was planned but the result rel is dummy, we assume
+				 * that it has been omitted from our plan tree (see
+				 * set_subquery_pathlist), and recurse to pull up its RTEs.
+				 *
+				 * Otherwise, it should be represented by a SubqueryScan node
+				 * somewhere in our plan tree, and we'll pull up its RTEs when
+				 * we process that plan node.
+				 *
+				 * However, if we're recursing, then we should pull up RTEs
+				 * whether the subquery is dummy or not, because we've found
+				 * that some upper query level is treating this one as dummy,
+				 * and so we won't scan this level's plan tree at all.
+				 */
+				if (rel->subroot == NULL)
+					flatten_unplanned_rtes(glob, rte);
+				else if (recursing ||
+						 IS_DUMMY_REL(fetch_upper_rel(rel->subroot,
+													  UPPERREL_FINAL, NULL)))
+					add_rtes_to_flat_rtable(rel->subroot, true);
+			}
+		}
+		rti++;
+	}
+}
+
+/*
+ * Extract RangeTblEntries from a subquery that was never planned at all
+ */
+static void
+flatten_unplanned_rtes(PlannerGlobal *glob, RangeTblEntry *rte)
+{
+	/* Use query_tree_walker to find all RTEs in the parse tree */
+	(void) query_tree_walker(rte->subquery,
+							 flatten_rtes_walker,
+							 (void *) glob,
+							 QTW_EXAMINE_RTES_BEFORE);
+}
+
+static bool
+flatten_rtes_walker(Node *node, PlannerGlobal *glob)
+{
+	if (node == NULL)
+		return false;
+	if (IsA(node, RangeTblEntry))
+	{
+		RangeTblEntry *rte = (RangeTblEntry *) node;
+
+		/* As above, we need only save relation RTEs */
+		if (rte->rtekind == RTE_RELATION)
+			add_rte_to_flat_rtable(glob, rte);
+		return false;
+	}
+	if (IsA(node, Query))
+	{
+		/* Recurse into subselects */
+		return query_tree_walker((Query *) node,
+								 flatten_rtes_walker,
+								 (void *) glob,
+								 QTW_EXAMINE_RTES_BEFORE);
+	}
+	return expression_tree_walker(node, flatten_rtes_walker,
+								  (void *) glob);
+}
+
+/*
+ * Add (a copy of) the given RTE to the final rangetable
+ *
+ * In the flat rangetable, we zero out substructure pointers that are not
+ * needed by the executor; this reduces the storage space and copying cost
+ * for cached plans.  We keep only the ctename, alias and eref Alias fields,
+ * which are needed by EXPLAIN, and the selectedCols, insertedCols,
+ * updatedCols, and extraUpdatedCols bitmaps, which are needed for
+ * executor-startup permissions checking and for trigger event checking.
+ */
+static void
+add_rte_to_flat_rtable(PlannerGlobal *glob, RangeTblEntry *rte)
+{
+	RangeTblEntry *newrte;
+
+	/* flat copy to duplicate all the scalar fields */
+	newrte = (RangeTblEntry *) palloc(sizeof(RangeTblEntry));
+	memcpy(newrte, rte, sizeof(RangeTblEntry));
+
+	/* zap unneeded sub-structure */
+	newrte->tablesample = NULL;
+	newrte->subquery = NULL;
+	newrte->joinaliasvars = NIL;
+	newrte->joinleftcols = NIL;
+	newrte->joinrightcols = NIL;
+	newrte->join_using_alias = NULL;
+	newrte->functions = NIL;
+	newrte->tablefunc = NULL;
+	newrte->values_lists = NIL;
+	newrte->coltypes = NIL;
+	newrte->coltypmods = NIL;
+	newrte->colcollations = NIL;
+	newrte->securityQuals = NIL;
+
+	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.
+	 *
+	 * We do this even though the RTE might be unreferenced in the plan tree;
+	 * this would correspond to cases such as views that were expanded, child
+	 * tables that were eliminated by constraint exclusion, etc. Schema
+	 * invalidation on such a rel must still force rebuilding of the plan.
+	 *
+	 * Note we don't bother to avoid making duplicate list entries.  We could,
+	 * but it would probably cost more cycles than it would save.
+	 */
+	if (newrte->rtekind == RTE_RELATION)
+		glob->relationOids = lappend_oid(glob->relationOids, newrte->relid);
+}
+
+/*
+ * set_plan_refs: recurse through the Plan nodes of a single subquery level
+ */
+static Plan *
+set_plan_refs(PlannerInfo *root, Plan *plan, int rtoffset)
+{
+	ListCell   *l;
+
+	if (plan == NULL)
+		return NULL;
+
+	/* Assign this node a unique ID. */
+	plan->plan_node_id = root->glob->lastPlanNodeId++;
+
+	/*
+	 * Plan-type-specific fixes
+	 */
+	switch (nodeTag(plan))
+	{
+		case T_SeqScan:
+			{
+				SeqScan    *splan = (SeqScan *) plan;
+
+				splan->scanrelid += rtoffset;
+				splan->plan.targetlist =
+					fix_scan_list(root, splan->plan.targetlist,
+								  rtoffset, NUM_EXEC_TLIST(plan));
+				splan->plan.qual =
+					fix_scan_list(root, splan->plan.qual,
+								  rtoffset, NUM_EXEC_QUAL(plan));
+			}
+			break;
+		case T_SampleScan:
+			{
+				SampleScan *splan = (SampleScan *) plan;
+
+				splan->scan.scanrelid += rtoffset;
+				splan->scan.plan.targetlist =
+					fix_scan_list(root, splan->scan.plan.targetlist,
+								  rtoffset, NUM_EXEC_TLIST(plan));
+				splan->scan.plan.qual =
+					fix_scan_list(root, splan->scan.plan.qual,
+								  rtoffset, NUM_EXEC_QUAL(plan));
+				splan->tablesample = (TableSampleClause *)
+					fix_scan_expr(root, (Node *) splan->tablesample,
+								  rtoffset, 1);
+			}
+			break;
+		case T_IndexScan:
+			{
+				IndexScan  *splan = (IndexScan *) plan;
+
+				splan->scan.scanrelid += rtoffset;
+				splan->scan.plan.targetlist =
+					fix_scan_list(root, splan->scan.plan.targetlist,
+								  rtoffset, NUM_EXEC_TLIST(plan));
+				splan->scan.plan.qual =
+					fix_scan_list(root, splan->scan.plan.qual,
+								  rtoffset, NUM_EXEC_QUAL(plan));
+				splan->indexqual =
+					fix_scan_list(root, splan->indexqual,
+								  rtoffset, 1);
+				splan->indexqualorig =
+					fix_scan_list(root, splan->indexqualorig,
+								  rtoffset, NUM_EXEC_QUAL(plan));
+				splan->indexorderby =
+					fix_scan_list(root, splan->indexorderby,
+								  rtoffset, 1);
+				splan->indexorderbyorig =
+					fix_scan_list(root, splan->indexorderbyorig,
+								  rtoffset, NUM_EXEC_QUAL(plan));
+			}
+			break;
+		case T_IndexOnlyScan:
+			{
+				IndexOnlyScan *splan = (IndexOnlyScan *) plan;
+
+				return set_indexonlyscan_references(root, splan, rtoffset);
+			}
+			break;
+		case T_BitmapIndexScan:
+			{
+				BitmapIndexScan *splan = (BitmapIndexScan *) plan;
+
+				splan->scan.scanrelid += rtoffset;
+				/* no need to fix targetlist and qual */
+				Assert(splan->scan.plan.targetlist == NIL);
+				Assert(splan->scan.plan.qual == NIL);
+				splan->indexqual =
+					fix_scan_list(root, splan->indexqual, rtoffset, 1);
+				splan->indexqualorig =
+					fix_scan_list(root, splan->indexqualorig,
+								  rtoffset, NUM_EXEC_QUAL(plan));
+			}
+			break;
+		case T_BitmapHeapScan:
+			{
+				BitmapHeapScan *splan = (BitmapHeapScan *) plan;
+
+				splan->scan.scanrelid += rtoffset;
+				splan->scan.plan.targetlist =
+					fix_scan_list(root, splan->scan.plan.targetlist,
+								  rtoffset, NUM_EXEC_TLIST(plan));
+				splan->scan.plan.qual =
+					fix_scan_list(root, splan->scan.plan.qual,
+								  rtoffset, NUM_EXEC_QUAL(plan));
+				splan->bitmapqualorig =
+					fix_scan_list(root, splan->bitmapqualorig,
+								  rtoffset, NUM_EXEC_QUAL(plan));
+			}
+			break;
+		case T_TidScan:
+			{
+				TidScan    *splan = (TidScan *) plan;
+
+				splan->scan.scanrelid += rtoffset;
+				splan->scan.plan.targetlist =
+					fix_scan_list(root, splan->scan.plan.targetlist,
+								  rtoffset, NUM_EXEC_TLIST(plan));
+				splan->scan.plan.qual =
+					fix_scan_list(root, splan->scan.plan.qual,
+								  rtoffset, NUM_EXEC_QUAL(plan));
+				splan->tidquals =
+					fix_scan_list(root, splan->tidquals,
+								  rtoffset, 1);
+			}
+			break;
+		case T_TidRangeScan:
+			{
+				TidRangeScan *splan = (TidRangeScan *) plan;
+
+				splan->scan.scanrelid += rtoffset;
+				splan->scan.plan.targetlist =
+					fix_scan_list(root, splan->scan.plan.targetlist,
+								  rtoffset, NUM_EXEC_TLIST(plan));
+				splan->scan.plan.qual =
+					fix_scan_list(root, splan->scan.plan.qual,
+								  rtoffset, NUM_EXEC_QUAL(plan));
+				splan->tidrangequals =
+					fix_scan_list(root, splan->tidrangequals,
+								  rtoffset, 1);
+			}
+			break;
+		case T_SubqueryScan:
+			/* Needs special treatment, see comments below */
+			return set_subqueryscan_references(root,
+											   (SubqueryScan *) plan,
+											   rtoffset);
+		case T_FunctionScan:
+			{
+				FunctionScan *splan = (FunctionScan *) plan;
+
+				splan->scan.scanrelid += rtoffset;
+				splan->scan.plan.targetlist =
+					fix_scan_list(root, splan->scan.plan.targetlist,
+								  rtoffset, NUM_EXEC_TLIST(plan));
+				splan->scan.plan.qual =
+					fix_scan_list(root, splan->scan.plan.qual,
+								  rtoffset, NUM_EXEC_QUAL(plan));
+				splan->functions =
+					fix_scan_list(root, splan->functions, rtoffset, 1);
+			}
+			break;
+		case T_TableFuncScan:
+			{
+				TableFuncScan *splan = (TableFuncScan *) plan;
+
+				splan->scan.scanrelid += rtoffset;
+				splan->scan.plan.targetlist =
+					fix_scan_list(root, splan->scan.plan.targetlist,
+								  rtoffset, NUM_EXEC_TLIST(plan));
+				splan->scan.plan.qual =
+					fix_scan_list(root, splan->scan.plan.qual,
+								  rtoffset, NUM_EXEC_QUAL(plan));
+				splan->tablefunc = (TableFunc *)
+					fix_scan_expr(root, (Node *) splan->tablefunc,
+								  rtoffset, 1);
+			}
+			break;
+		case T_ValuesScan:
+			{
+				ValuesScan *splan = (ValuesScan *) plan;
+
+				splan->scan.scanrelid += rtoffset;
+				splan->scan.plan.targetlist =
+					fix_scan_list(root, splan->scan.plan.targetlist,
+								  rtoffset, NUM_EXEC_TLIST(plan));
+				splan->scan.plan.qual =
+					fix_scan_list(root, splan->scan.plan.qual,
+								  rtoffset, NUM_EXEC_QUAL(plan));
+				splan->values_lists =
+					fix_scan_list(root, splan->values_lists,
+								  rtoffset, 1);
+			}
+			break;
+		case T_CteScan:
+			{
+				CteScan    *splan = (CteScan *) plan;
+
+				splan->scan.scanrelid += rtoffset;
+				splan->scan.plan.targetlist =
+					fix_scan_list(root, splan->scan.plan.targetlist,
+								  rtoffset, NUM_EXEC_TLIST(plan));
+				splan->scan.plan.qual =
+					fix_scan_list(root, splan->scan.plan.qual,
+								  rtoffset, NUM_EXEC_QUAL(plan));
+			}
+			break;
+		case T_NamedTuplestoreScan:
+			{
+				NamedTuplestoreScan *splan = (NamedTuplestoreScan *) plan;
+
+				splan->scan.scanrelid += rtoffset;
+				splan->scan.plan.targetlist =
+					fix_scan_list(root, splan->scan.plan.targetlist,
+								  rtoffset, NUM_EXEC_TLIST(plan));
+				splan->scan.plan.qual =
+					fix_scan_list(root, splan->scan.plan.qual,
+								  rtoffset, NUM_EXEC_QUAL(plan));
+			}
+			break;
+		case T_WorkTableScan:
+			{
+				WorkTableScan *splan = (WorkTableScan *) plan;
+
+				splan->scan.scanrelid += rtoffset;
+				splan->scan.plan.targetlist =
+					fix_scan_list(root, splan->scan.plan.targetlist,
+								  rtoffset, NUM_EXEC_TLIST(plan));
+				splan->scan.plan.qual =
+					fix_scan_list(root, splan->scan.plan.qual,
+								  rtoffset, NUM_EXEC_QUAL(plan));
+			}
+			break;
+		case T_ForeignScan:
+			set_foreignscan_references(root, (ForeignScan *) plan, rtoffset);
+			break;
+		case T_CustomScan:
+			set_customscan_references(root, (CustomScan *) plan, rtoffset);
+			break;
+
+		case T_NestLoop:
+		case T_MergeJoin:
+		case T_HashJoin:
+			set_join_references(root, (Join *) plan, rtoffset);
+			break;
+
+		case T_Gather:
+		case T_GatherMerge:
+			{
+				set_upper_references(root, plan, rtoffset);
+				set_param_references(root, plan);
+			}
+			break;
+
+		case T_Hash:
+			set_hash_references(root, plan, rtoffset);
+			break;
+
+		case T_Memoize:
+			{
+				Memoize    *mplan = (Memoize *) plan;
+
+				/*
+				 * Memoize does not evaluate its targetlist.  It just uses the
+				 * same targetlist from its outer subnode.
+				 */
+				set_dummy_tlist_references(plan, rtoffset);
+
+				mplan->param_exprs = fix_scan_list(root, mplan->param_exprs,
+												   rtoffset,
+												   NUM_EXEC_TLIST(plan));
+				break;
+			}
+
+		case T_Material:
+		case T_Sort:
+		case T_IncrementalSort:
+		case T_Unique:
+		case T_SetOp:
+
+			/*
+			 * These plan types don't actually bother to evaluate their
+			 * targetlists, because they just return their unmodified input
+			 * tuples.  Even though the targetlist won't be used by the
+			 * executor, we fix it up for possible use by EXPLAIN (not to
+			 * mention ease of debugging --- wrong varnos are very confusing).
+			 */
+			set_dummy_tlist_references(plan, rtoffset);
+
+			/*
+			 * Since these plan types don't check quals either, we should not
+			 * find any qual expression attached to them.
+			 */
+			Assert(plan->qual == NIL);
+			break;
+		case T_LockRows:
+			{
+				LockRows   *splan = (LockRows *) plan;
+
+				/*
+				 * Like the plan types above, LockRows doesn't evaluate its
+				 * tlist or quals.  But we have to fix up the RT indexes in
+				 * its rowmarks.
+				 */
+				set_dummy_tlist_references(plan, rtoffset);
+				Assert(splan->plan.qual == NIL);
+
+				foreach(l, splan->rowMarks)
+				{
+					PlanRowMark *rc = (PlanRowMark *) lfirst(l);
+
+					rc->rti += rtoffset;
+					rc->prti += rtoffset;
+				}
+			}
+			break;
+		case T_Limit:
+			{
+				Limit	   *splan = (Limit *) plan;
+
+				/*
+				 * Like the plan types above, Limit doesn't evaluate its tlist
+				 * or quals.  It does have live expressions for limit/offset,
+				 * however; and those cannot contain subplan variable refs, so
+				 * fix_scan_expr works for them.
+				 */
+				set_dummy_tlist_references(plan, rtoffset);
+				Assert(splan->plan.qual == NIL);
+
+				splan->limitOffset =
+					fix_scan_expr(root, splan->limitOffset, rtoffset, 1);
+				splan->limitCount =
+					fix_scan_expr(root, splan->limitCount, rtoffset, 1);
+			}
+			break;
+		case T_Agg:
+			{
+				Agg		   *agg = (Agg *) plan;
+
+				/*
+				 * If this node is combining partial-aggregation results, we
+				 * must convert its Aggrefs to contain references to the
+				 * partial-aggregate subexpressions that will be available
+				 * from the child plan node.
+				 */
+				if (DO_AGGSPLIT_COMBINE(agg->aggsplit))
+				{
+					plan->targetlist = (List *)
+						convert_combining_aggrefs((Node *) plan->targetlist,
+												  NULL);
+					plan->qual = (List *)
+						convert_combining_aggrefs((Node *) plan->qual,
+												  NULL);
+				}
+
+				set_upper_references(root, plan, rtoffset);
+			}
+			break;
+		case T_Group:
+			set_upper_references(root, plan, rtoffset);
+			break;
+		case T_WindowAgg:
+			{
+				WindowAgg  *wplan = (WindowAgg *) plan;
+
+				set_upper_references(root, plan, rtoffset);
+
+				/*
+				 * Like Limit node limit/offset expressions, WindowAgg has
+				 * frame offset expressions, which cannot contain subplan
+				 * variable refs, so fix_scan_expr works for them.
+				 */
+				wplan->startOffset =
+					fix_scan_expr(root, wplan->startOffset, rtoffset, 1);
+				wplan->endOffset =
+					fix_scan_expr(root, wplan->endOffset, rtoffset, 1);
+			}
+			break;
+		case T_Result:
+			{
+				Result	   *splan = (Result *) plan;
+
+				/*
+				 * Result may or may not have a subplan; if not, it's more
+				 * like a scan node than an upper node.
+				 */
+				if (splan->plan.lefttree != NULL)
+					set_upper_references(root, plan, rtoffset);
+				else
+				{
+					/*
+					 * The tlist of a childless Result could contain
+					 * unresolved ROWID_VAR Vars, in case it's representing a
+					 * target relation which is completely empty because of
+					 * constraint exclusion.  Replace any such Vars by null
+					 * constants, as though they'd been resolved for a leaf
+					 * scan node that doesn't support them.  We could have
+					 * fix_scan_expr do this, but since the case is only
+					 * expected to occur here, it seems safer to special-case
+					 * it here and keep the assertions that ROWID_VARs
+					 * shouldn't be seen by fix_scan_expr.
+					 */
+					foreach(l, splan->plan.targetlist)
+					{
+						TargetEntry *tle = (TargetEntry *) lfirst(l);
+						Var		   *var = (Var *) tle->expr;
+
+						if (var && IsA(var, Var) && var->varno == ROWID_VAR)
+							tle->expr = (Expr *) makeNullConst(var->vartype,
+															   var->vartypmod,
+															   var->varcollid);
+					}
+
+					splan->plan.targetlist =
+						fix_scan_list(root, splan->plan.targetlist,
+									  rtoffset, NUM_EXEC_TLIST(plan));
+					splan->plan.qual =
+						fix_scan_list(root, splan->plan.qual,
+									  rtoffset, NUM_EXEC_QUAL(plan));
+				}
+				/* resconstantqual can't contain any subplan variable refs */
+				splan->resconstantqual =
+					fix_scan_expr(root, splan->resconstantqual, rtoffset, 1);
+			}
+			break;
+		case T_ProjectSet:
+			set_upper_references(root, plan, rtoffset);
+			break;
+		case T_ModifyTable:
+			{
+				ModifyTable *splan = (ModifyTable *) plan;
+
+				Assert(splan->plan.targetlist == NIL);
+				Assert(splan->plan.qual == NIL);
+
+				splan->withCheckOptionLists =
+					fix_scan_list(root, splan->withCheckOptionLists,
+								  rtoffset, 1);
+
+				if (splan->returningLists)
+				{
+					List	   *newRL = NIL;
+					Plan	   *subplan = outerPlan(splan);
+					ListCell   *lcrl,
+							   *lcrr;
+
+					/*
+					 * Pass each per-resultrel returningList through
+					 * set_returning_clause_references().
+					 */
+					Assert(list_length(splan->returningLists) == list_length(splan->resultRelations));
+					forboth(lcrl, splan->returningLists,
+							lcrr, splan->resultRelations)
+					{
+						List	   *rlist = (List *) lfirst(lcrl);
+						Index		resultrel = lfirst_int(lcrr);
+
+						rlist = set_returning_clause_references(root,
+																rlist,
+																subplan,
+																resultrel,
+																rtoffset);
+						newRL = lappend(newRL, rlist);
+					}
+					splan->returningLists = newRL;
+
+					/*
+					 * Set up the visible plan targetlist as being the same as
+					 * the first RETURNING list. This is for the use of
+					 * EXPLAIN; the executor won't pay any attention to the
+					 * targetlist.  We postpone this step until here so that
+					 * we don't have to do set_returning_clause_references()
+					 * twice on identical targetlists.
+					 */
+					splan->plan.targetlist = copyObject(linitial(newRL));
+				}
+
+				/*
+				 * We treat ModifyTable with ON CONFLICT as a form of 'pseudo
+				 * join', where the inner side is the EXCLUDED tuple.
+				 * Therefore use fix_join_expr to setup the relevant variables
+				 * to INNER_VAR. We explicitly don't create any OUTER_VARs as
+				 * those are already used by RETURNING and it seems better to
+				 * be non-conflicting.
+				 */
+				if (splan->onConflictSet)
+				{
+					indexed_tlist *itlist;
+
+					itlist = build_tlist_index(splan->exclRelTlist);
+
+					splan->onConflictSet =
+						fix_join_expr(root, splan->onConflictSet,
+									  NULL, itlist,
+									  linitial_int(splan->resultRelations),
+									  rtoffset, NUM_EXEC_QUAL(plan));
+
+					splan->onConflictWhere = (Node *)
+						fix_join_expr(root, (List *) splan->onConflictWhere,
+									  NULL, itlist,
+									  linitial_int(splan->resultRelations),
+									  rtoffset, NUM_EXEC_QUAL(plan));
+
+					pfree(itlist);
+
+					splan->exclRelTlist =
+						fix_scan_list(root, splan->exclRelTlist, rtoffset, 1);
+				}
+
+				splan->nominalRelation += rtoffset;
+				if (splan->rootRelation)
+					splan->rootRelation += rtoffset;
+				splan->exclRelRTI += rtoffset;
+
+				foreach(l, splan->resultRelations)
+				{
+					lfirst_int(l) += rtoffset;
+				}
+				foreach(l, splan->rowMarks)
+				{
+					PlanRowMark *rc = (PlanRowMark *) lfirst(l);
+
+					rc->rti += rtoffset;
+					rc->prti += rtoffset;
+				}
+
+				/*
+				 * Append this ModifyTable node's final result relation RT
+				 * index(es) to the global list for the plan.
+				 */
+				root->glob->resultRelations =
+					list_concat(root->glob->resultRelations,
+								splan->resultRelations);
+				if (splan->rootRelation)
+				{
+					root->glob->resultRelations =
+						lappend_int(root->glob->resultRelations,
+									splan->rootRelation);
+				}
+			}
+			break;
+		case T_Append:
+			/* Needs special treatment, see comments below */
+			return set_append_references(root,
+										 (Append *) plan,
+										 rtoffset);
+		case T_MergeAppend:
+			/* Needs special treatment, see comments below */
+			return set_mergeappend_references(root,
+											  (MergeAppend *) plan,
+											  rtoffset);
+		case T_RecursiveUnion:
+			/* This doesn't evaluate targetlist or check quals either */
+			set_dummy_tlist_references(plan, rtoffset);
+			Assert(plan->qual == NIL);
+			break;
+		case T_BitmapAnd:
+			{
+				BitmapAnd  *splan = (BitmapAnd *) plan;
+
+				/* BitmapAnd works like Append, but has no tlist */
+				Assert(splan->plan.targetlist == NIL);
+				Assert(splan->plan.qual == NIL);
+				foreach(l, splan->bitmapplans)
+				{
+					lfirst(l) = set_plan_refs(root,
+											  (Plan *) lfirst(l),
+											  rtoffset);
+				}
+			}
+			break;
+		case T_BitmapOr:
+			{
+				BitmapOr   *splan = (BitmapOr *) plan;
+
+				/* BitmapOr works like Append, but has no tlist */
+				Assert(splan->plan.targetlist == NIL);
+				Assert(splan->plan.qual == NIL);
+				foreach(l, splan->bitmapplans)
+				{
+					lfirst(l) = set_plan_refs(root,
+											  (Plan *) lfirst(l),
+											  rtoffset);
+				}
+			}
+			break;
+		default:
+			elog(ERROR, "unrecognized node type: %d",
+				 (int) nodeTag(plan));
+			break;
+	}
+
+	/*
+	 * Now recurse into child plans, if any
+	 *
+	 * NOTE: it is essential that we recurse into child plans AFTER we set
+	 * subplan references in this plan's tlist and quals.  If we did the
+	 * reference-adjustments bottom-up, then we would fail to match this
+	 * plan's var nodes against the already-modified nodes of the children.
+	 */
+	plan->lefttree = set_plan_refs(root, plan->lefttree, rtoffset);
+	plan->righttree = set_plan_refs(root, plan->righttree, rtoffset);
+
+	return plan;
+}
+
+/*
+ * set_indexonlyscan_references
+ *		Do set_plan_references processing on an IndexOnlyScan
+ *
+ * This is unlike the handling of a plain IndexScan because we have to
+ * convert Vars referencing the heap into Vars referencing the index.
+ * We can use the fix_upper_expr machinery for that, by working from a
+ * targetlist describing the index columns.
+ */
+static Plan *
+set_indexonlyscan_references(PlannerInfo *root,
+							 IndexOnlyScan *plan,
+							 int rtoffset)
+{
+	indexed_tlist *index_itlist;
+	List	   *stripped_indextlist;
+	ListCell   *lc;
+
+	/*
+	 * Vars in the plan node's targetlist, qual, and recheckqual must only
+	 * reference columns that the index AM can actually return.  To ensure
+	 * this, remove non-returnable columns (which are marked as resjunk) from
+	 * the indexed tlist.  We can just drop them because the indexed_tlist
+	 * machinery pays attention to TLE resnos, not physical list position.
+	 */
+	stripped_indextlist = NIL;
+	foreach(lc, plan->indextlist)
+	{
+		TargetEntry *indextle = (TargetEntry *) lfirst(lc);
+
+		if (!indextle->resjunk)
+			stripped_indextlist = lappend(stripped_indextlist, indextle);
+	}
+
+	index_itlist = build_tlist_index(stripped_indextlist);
+
+	plan->scan.scanrelid += rtoffset;
+	plan->scan.plan.targetlist = (List *)
+		fix_upper_expr(root,
+					   (Node *) plan->scan.plan.targetlist,
+					   index_itlist,
+					   INDEX_VAR,
+					   rtoffset,
+					   NUM_EXEC_TLIST((Plan *) plan));
+	plan->scan.plan.qual = (List *)
+		fix_upper_expr(root,
+					   (Node *) plan->scan.plan.qual,
+					   index_itlist,
+					   INDEX_VAR,
+					   rtoffset,
+					   NUM_EXEC_QUAL((Plan *) plan));
+	plan->recheckqual = (List *)
+		fix_upper_expr(root,
+					   (Node *) plan->recheckqual,
+					   index_itlist,
+					   INDEX_VAR,
+					   rtoffset,
+					   NUM_EXEC_QUAL((Plan *) plan));
+	/* indexqual is already transformed to reference index columns */
+	plan->indexqual = fix_scan_list(root, plan->indexqual,
+									rtoffset, 1);
+	/* indexorderby is already transformed to reference index columns */
+	plan->indexorderby = fix_scan_list(root, plan->indexorderby,
+									   rtoffset, 1);
+	/* indextlist must NOT be transformed to reference index columns */
+	plan->indextlist = fix_scan_list(root, plan->indextlist,
+									 rtoffset, NUM_EXEC_TLIST((Plan *) plan));
+
+	pfree(index_itlist);
+
+	return (Plan *) plan;
+}
+
+/*
+ * set_subqueryscan_references
+ *		Do set_plan_references processing on a SubqueryScan
+ *
+ * We try to strip out the SubqueryScan entirely; if we can't, we have
+ * to do the normal processing on it.
+ */
+static Plan *
+set_subqueryscan_references(PlannerInfo *root,
+							SubqueryScan *plan,
+							int rtoffset)
+{
+	RelOptInfo *rel;
+	Plan	   *result;
+
+	/* Need to look up the subquery's RelOptInfo, since we need its subroot */
+	rel = find_base_rel(root, plan->scan.scanrelid);
+
+	/* Recursively process the subplan */
+	plan->subplan = set_plan_references(rel->subroot, plan->subplan);
+
+	if (trivial_subqueryscan(plan))
+	{
+		/*
+		 * We can omit the SubqueryScan node and just pull up the subplan.
+		 */
+		result = clean_up_removed_plan_level((Plan *) plan, plan->subplan);
+	}
+	else
+	{
+		/*
+		 * Keep the SubqueryScan node.  We have to do the processing that
+		 * set_plan_references would otherwise have done on it.  Notice we do
+		 * not do set_upper_references() here, because a SubqueryScan will
+		 * always have been created with correct references to its subplan's
+		 * outputs to begin with.
+		 */
+		plan->scan.scanrelid += rtoffset;
+		plan->scan.plan.targetlist =
+			fix_scan_list(root, plan->scan.plan.targetlist,
+						  rtoffset, NUM_EXEC_TLIST((Plan *) plan));
+		plan->scan.plan.qual =
+			fix_scan_list(root, plan->scan.plan.qual,
+						  rtoffset, NUM_EXEC_QUAL((Plan *) plan));
+
+		result = (Plan *) plan;
+	}
+
+	return result;
+}
+
+/*
+ * trivial_subqueryscan
+ *		Detect whether a SubqueryScan can be deleted from the plan tree.
+ *
+ * We can delete it if it has no qual to check and the targetlist just
+ * regurgitates the output of the child plan.
+ */
+static bool
+trivial_subqueryscan(SubqueryScan *plan)
+{
+	int			attrno;
+	ListCell   *lp,
+			   *lc;
+
+	if (plan->scan.plan.qual != NIL)
+		return false;
+
+	if (list_length(plan->scan.plan.targetlist) !=
+		list_length(plan->subplan->targetlist))
+		return false;			/* tlists not same length */
+
+	attrno = 1;
+	forboth(lp, plan->scan.plan.targetlist, lc, plan->subplan->targetlist)
+	{
+		TargetEntry *ptle = (TargetEntry *) lfirst(lp);
+		TargetEntry *ctle = (TargetEntry *) lfirst(lc);
+
+		if (ptle->resjunk != ctle->resjunk)
+			return false;		/* tlist doesn't match junk status */
+
+		/*
+		 * We accept either a Var referencing the corresponding element of the
+		 * subplan tlist, or a Const equaling the subplan element. See
+		 * generate_setop_tlist() for motivation.
+		 */
+		if (ptle->expr && IsA(ptle->expr, Var))
+		{
+			Var		   *var = (Var *) ptle->expr;
+
+			Assert(var->varno == plan->scan.scanrelid);
+			Assert(var->varlevelsup == 0);
+			if (var->varattno != attrno)
+				return false;	/* out of order */
+		}
+		else if (ptle->expr && IsA(ptle->expr, Const))
+		{
+			if (!equal(ptle->expr, ctle->expr))
+				return false;
+		}
+		else
+			return false;
+
+		attrno++;
+	}
+
+	return true;
+}
+
+/*
+ * clean_up_removed_plan_level
+ *		Do necessary cleanup when we strip out a SubqueryScan, Append, etc
+ *
+ * We are dropping the "parent" plan in favor of returning just its "child".
+ * A few small tweaks are needed.
+ */
+static Plan *
+clean_up_removed_plan_level(Plan *parent, Plan *child)
+{
+	/* We have to be sure we don't lose any initplans */
+	child->initPlan = list_concat(parent->initPlan,
+								  child->initPlan);
+
+	/*
+	 * We also have to transfer the parent's column labeling info into the
+	 * child, else columns sent to client will be improperly labeled if this
+	 * is the topmost plan level.  resjunk and so on may be important too.
+	 */
+	apply_tlist_labeling(child->targetlist, parent->targetlist);
+
+	return child;
+}
+
+/*
+ * set_foreignscan_references
+ *	   Do set_plan_references processing on a ForeignScan
+ */
+static void
+set_foreignscan_references(PlannerInfo *root,
+						   ForeignScan *fscan,
+						   int rtoffset)
+{
+	/* Adjust scanrelid if it's valid */
+	if (fscan->scan.scanrelid > 0)
+		fscan->scan.scanrelid += rtoffset;
+
+	if (fscan->fdw_scan_tlist != NIL || fscan->scan.scanrelid == 0)
+	{
+		/*
+		 * Adjust tlist, qual, fdw_exprs, fdw_recheck_quals to reference
+		 * foreign scan tuple
+		 */
+		indexed_tlist *itlist = build_tlist_index(fscan->fdw_scan_tlist);
+
+		fscan->scan.plan.targetlist = (List *)
+			fix_upper_expr(root,
+						   (Node *) fscan->scan.plan.targetlist,
+						   itlist,
+						   INDEX_VAR,
+						   rtoffset,
+						   NUM_EXEC_TLIST((Plan *) fscan));
+		fscan->scan.plan.qual = (List *)
+			fix_upper_expr(root,
+						   (Node *) fscan->scan.plan.qual,
+						   itlist,
+						   INDEX_VAR,
+						   rtoffset,
+						   NUM_EXEC_QUAL((Plan *) fscan));
+		fscan->fdw_exprs = (List *)
+			fix_upper_expr(root,
+						   (Node *) fscan->fdw_exprs,
+						   itlist,
+						   INDEX_VAR,
+						   rtoffset,
+						   NUM_EXEC_QUAL((Plan *) fscan));
+		fscan->fdw_recheck_quals = (List *)
+			fix_upper_expr(root,
+						   (Node *) fscan->fdw_recheck_quals,
+						   itlist,
+						   INDEX_VAR,
+						   rtoffset,
+						   NUM_EXEC_QUAL((Plan *) fscan));
+		pfree(itlist);
+		/* fdw_scan_tlist itself just needs fix_scan_list() adjustments */
+		fscan->fdw_scan_tlist =
+			fix_scan_list(root, fscan->fdw_scan_tlist,
+						  rtoffset, NUM_EXEC_TLIST((Plan *) fscan));
+	}
+	else
+	{
+		/*
+		 * Adjust tlist, qual, fdw_exprs, fdw_recheck_quals in the standard
+		 * way
+		 */
+		fscan->scan.plan.targetlist =
+			fix_scan_list(root, fscan->scan.plan.targetlist,
+						  rtoffset, NUM_EXEC_TLIST((Plan *) fscan));
+		fscan->scan.plan.qual =
+			fix_scan_list(root, fscan->scan.plan.qual,
+						  rtoffset, NUM_EXEC_QUAL((Plan *) fscan));
+		fscan->fdw_exprs =
+			fix_scan_list(root, fscan->fdw_exprs,
+						  rtoffset, NUM_EXEC_QUAL((Plan *) fscan));
+		fscan->fdw_recheck_quals =
+			fix_scan_list(root, fscan->fdw_recheck_quals,
+						  rtoffset, NUM_EXEC_QUAL((Plan *) fscan));
+	}
+
+	fscan->fs_relids = offset_relid_set(fscan->fs_relids, rtoffset);
+
+	/* Adjust resultRelation if it's valid */
+	if (fscan->resultRelation > 0)
+		fscan->resultRelation += rtoffset;
+}
+
+/*
+ * set_customscan_references
+ *	   Do set_plan_references processing on a CustomScan
+ */
+static void
+set_customscan_references(PlannerInfo *root,
+						  CustomScan *cscan,
+						  int rtoffset)
+{
+	ListCell   *lc;
+
+	/* Adjust scanrelid if it's valid */
+	if (cscan->scan.scanrelid > 0)
+		cscan->scan.scanrelid += rtoffset;
+
+	if (cscan->custom_scan_tlist != NIL || cscan->scan.scanrelid == 0)
+	{
+		/* Adjust tlist, qual, custom_exprs to reference custom scan tuple */
+		indexed_tlist *itlist = build_tlist_index(cscan->custom_scan_tlist);
+
+		cscan->scan.plan.targetlist = (List *)
+			fix_upper_expr(root,
+						   (Node *) cscan->scan.plan.targetlist,
+						   itlist,
+						   INDEX_VAR,
+						   rtoffset,
+						   NUM_EXEC_TLIST((Plan *) cscan));
+		cscan->scan.plan.qual = (List *)
+			fix_upper_expr(root,
+						   (Node *) cscan->scan.plan.qual,
+						   itlist,
+						   INDEX_VAR,
+						   rtoffset,
+						   NUM_EXEC_QUAL((Plan *) cscan));
+		cscan->custom_exprs = (List *)
+			fix_upper_expr(root,
+						   (Node *) cscan->custom_exprs,
+						   itlist,
+						   INDEX_VAR,
+						   rtoffset,
+						   NUM_EXEC_QUAL((Plan *) cscan));
+		pfree(itlist);
+		/* custom_scan_tlist itself just needs fix_scan_list() adjustments */
+		cscan->custom_scan_tlist =
+			fix_scan_list(root, cscan->custom_scan_tlist,
+						  rtoffset, NUM_EXEC_TLIST((Plan *) cscan));
+	}
+	else
+	{
+		/* Adjust tlist, qual, custom_exprs in the standard way */
+		cscan->scan.plan.targetlist =
+			fix_scan_list(root, cscan->scan.plan.targetlist,
+						  rtoffset, NUM_EXEC_TLIST((Plan *) cscan));
+		cscan->scan.plan.qual =
+			fix_scan_list(root, cscan->scan.plan.qual,
+						  rtoffset, NUM_EXEC_QUAL((Plan *) cscan));
+		cscan->custom_exprs =
+			fix_scan_list(root, cscan->custom_exprs,
+						  rtoffset, NUM_EXEC_QUAL((Plan *) cscan));
+	}
+
+	/* Adjust child plan-nodes recursively, if needed */
+	foreach(lc, cscan->custom_plans)
+	{
+		lfirst(lc) = set_plan_refs(root, (Plan *) lfirst(lc), rtoffset);
+	}
+
+	cscan->custom_relids = offset_relid_set(cscan->custom_relids, rtoffset);
+}
+
+/*
+ * set_append_references
+ *		Do set_plan_references processing on an Append
+ *
+ * We try to strip out the Append entirely; if we can't, we have
+ * to do the normal processing on it.
+ */
+static Plan *
+set_append_references(PlannerInfo *root,
+					  Append *aplan,
+					  int rtoffset)
+{
+	ListCell   *l;
+
+	/*
+	 * Append, like Sort et al, doesn't actually evaluate its targetlist or
+	 * check quals.  If it's got exactly one child plan, then it's not doing
+	 * anything useful at all, and we can strip it out.
+	 */
+	Assert(aplan->plan.qual == NIL);
+
+	/* First, we gotta recurse on the children */
+	foreach(l, aplan->appendplans)
+	{
+		lfirst(l) = set_plan_refs(root, (Plan *) lfirst(l), rtoffset);
+	}
+
+	/*
+	 * See if it's safe to get rid of the Append entirely.  For this to be
+	 * safe, there must be only one child plan and that child plan's parallel
+	 * awareness must match that of the Append's.  The reason for the latter
+	 * is that the if the Append is parallel aware and the child is not then
+	 * the calling plan may execute the non-parallel aware child multiple
+	 * times.
+	 */
+	if (list_length(aplan->appendplans) == 1 &&
+		((Plan *) linitial(aplan->appendplans))->parallel_aware == aplan->plan.parallel_aware)
+		return clean_up_removed_plan_level((Plan *) aplan,
+										   (Plan *) linitial(aplan->appendplans));
+
+	/*
+	 * Otherwise, clean up the Append as needed.  It's okay to do this after
+	 * recursing to the children, because set_dummy_tlist_references doesn't
+	 * look at those.
+	 */
+	set_dummy_tlist_references((Plan *) aplan, rtoffset);
+
+	aplan->apprelids = offset_relid_set(aplan->apprelids, rtoffset);
+
+	if (aplan->part_prune_info)
+	{
+		foreach(l, aplan->part_prune_info->prune_infos)
+		{
+			List	   *prune_infos = lfirst(l);
+			ListCell   *l2;
+
+			foreach(l2, prune_infos)
+			{
+				PartitionedRelPruneInfo *pinfo = lfirst(l2);
+
+				pinfo->rtindex += rtoffset;
+			}
+		}
+	}
+
+	/* We don't need to recurse to lefttree or righttree ... */
+	Assert(aplan->plan.lefttree == NULL);
+	Assert(aplan->plan.righttree == NULL);
+
+	return (Plan *) aplan;
+}
+
+/*
+ * set_mergeappend_references
+ *		Do set_plan_references processing on a MergeAppend
+ *
+ * We try to strip out the MergeAppend entirely; if we can't, we have
+ * to do the normal processing on it.
+ */
+static Plan *
+set_mergeappend_references(PlannerInfo *root,
+						   MergeAppend *mplan,
+						   int rtoffset)
+{
+	ListCell   *l;
+
+	/*
+	 * MergeAppend, like Sort et al, doesn't actually evaluate its targetlist
+	 * or check quals.  If it's got exactly one child plan, then it's not
+	 * doing anything useful at all, and we can strip it out.
+	 */
+	Assert(mplan->plan.qual == NIL);
+
+	/* First, we gotta recurse on the children */
+	foreach(l, mplan->mergeplans)
+	{
+		lfirst(l) = set_plan_refs(root, (Plan *) lfirst(l), rtoffset);
+	}
+
+	/*
+	 * See if it's safe to get rid of the MergeAppend entirely.  For this to
+	 * be safe, there must be only one child plan and that child plan's
+	 * parallel awareness must match that of the MergeAppend's.  The reason
+	 * for the latter is that the if the MergeAppend is parallel aware and the
+	 * child is not then the calling plan may execute the non-parallel aware
+	 * child multiple times.
+	 */
+	if (list_length(mplan->mergeplans) == 1 &&
+		((Plan *) linitial(mplan->mergeplans))->parallel_aware == mplan->plan.parallel_aware)
+		return clean_up_removed_plan_level((Plan *) mplan,
+										   (Plan *) linitial(mplan->mergeplans));
+
+	/*
+	 * Otherwise, clean up the MergeAppend as needed.  It's okay to do this
+	 * after recursing to the children, because set_dummy_tlist_references
+	 * doesn't look at those.
+	 */
+	set_dummy_tlist_references((Plan *) mplan, rtoffset);
+
+	mplan->apprelids = offset_relid_set(mplan->apprelids, rtoffset);
+
+	if (mplan->part_prune_info)
+	{
+		foreach(l, mplan->part_prune_info->prune_infos)
+		{
+			List	   *prune_infos = lfirst(l);
+			ListCell   *l2;
+
+			foreach(l2, prune_infos)
+			{
+				PartitionedRelPruneInfo *pinfo = lfirst(l2);
+
+				pinfo->rtindex += rtoffset;
+			}
+		}
+	}
+
+	/* We don't need to recurse to lefttree or righttree ... */
+	Assert(mplan->plan.lefttree == NULL);
+	Assert(mplan->plan.righttree == NULL);
+
+	return (Plan *) mplan;
+}
+
+/*
+ * set_hash_references
+ *	   Do set_plan_references processing on a Hash node
+ */
+static void
+set_hash_references(PlannerInfo *root, Plan *plan, int rtoffset)
+{
+	Hash	   *hplan = (Hash *) plan;
+	Plan	   *outer_plan = plan->lefttree;
+	indexed_tlist *outer_itlist;
+
+	/*
+	 * Hash's hashkeys are used when feeding tuples into the hashtable,
+	 * therefore have them reference Hash's outer plan (which itself is the
+	 * inner plan of the HashJoin).
+	 */
+	outer_itlist = build_tlist_index(outer_plan->targetlist);
+	hplan->hashkeys = (List *)
+		fix_upper_expr(root,
+					   (Node *) hplan->hashkeys,
+					   outer_itlist,
+					   OUTER_VAR,
+					   rtoffset,
+					   NUM_EXEC_QUAL(plan));
+
+	/* Hash doesn't project */
+	set_dummy_tlist_references(plan, rtoffset);
+
+	/* Hash nodes don't have their own quals */
+	Assert(plan->qual == NIL);
+}
+
+/*
+ * offset_relid_set
+ *		Apply rtoffset to the members of a Relids set.
+ */
+static Relids
+offset_relid_set(Relids relids, int rtoffset)
+{
+	Relids		result = NULL;
+	int			rtindex;
+
+	/* If there's no offset to apply, we needn't recompute the value */
+	if (rtoffset == 0)
+		return relids;
+	rtindex = -1;
+	while ((rtindex = bms_next_member(relids, rtindex)) >= 0)
+		result = bms_add_member(result, rtindex + rtoffset);
+	return result;
+}
+
+/*
+ * copyVar
+ *		Copy a Var node.
+ *
+ * fix_scan_expr and friends do this enough times that it's worth having
+ * a bespoke routine instead of using the generic copyObject() function.
+ */
+static inline Var *
+copyVar(Var *var)
+{
+	Var		   *newvar = (Var *) palloc(sizeof(Var));
+
+	*newvar = *var;
+	return newvar;
+}
+
+/*
+ * fix_expr_common
+ *		Do generic set_plan_references processing on an expression node
+ *
+ * This is code that is common to all variants of expression-fixing.
+ * We must look up operator opcode info for OpExpr and related nodes,
+ * add OIDs from regclass Const nodes into root->glob->relationOids, and
+ * add PlanInvalItems for user-defined functions into root->glob->invalItems.
+ * We also fill in column index lists for GROUPING() expressions.
+ *
+ * We assume it's okay to update opcode info in-place.  So this could possibly
+ * scribble on the planner's input data structures, but it's OK.
+ */
+static void
+fix_expr_common(PlannerInfo *root, Node *node)
+{
+	/* We assume callers won't call us on a NULL pointer */
+	if (IsA(node, Aggref))
+	{
+		record_plan_function_dependency(root,
+										((Aggref *) node)->aggfnoid);
+	}
+	else if (IsA(node, WindowFunc))
+	{
+		record_plan_function_dependency(root,
+										((WindowFunc *) node)->winfnoid);
+	}
+	else if (IsA(node, FuncExpr))
+	{
+		record_plan_function_dependency(root,
+										((FuncExpr *) node)->funcid);
+	}
+	else if (IsA(node, OpExpr))
+	{
+		set_opfuncid((OpExpr *) node);
+		record_plan_function_dependency(root,
+										((OpExpr *) node)->opfuncid);
+	}
+	else if (IsA(node, DistinctExpr))
+	{
+		set_opfuncid((OpExpr *) node);	/* rely on struct equivalence */
+		record_plan_function_dependency(root,
+										((DistinctExpr *) node)->opfuncid);
+	}
+	else if (IsA(node, NullIfExpr))
+	{
+		set_opfuncid((OpExpr *) node);	/* rely on struct equivalence */
+		record_plan_function_dependency(root,
+										((NullIfExpr *) node)->opfuncid);
+	}
+	else if (IsA(node, ScalarArrayOpExpr))
+	{
+		ScalarArrayOpExpr *saop = (ScalarArrayOpExpr *) node;
+
+		set_sa_opfuncid(saop);
+		record_plan_function_dependency(root, saop->opfuncid);
+
+		if (!OidIsValid(saop->hashfuncid))
+			record_plan_function_dependency(root, saop->hashfuncid);
+	}
+	else if (IsA(node, Const))
+	{
+		Const	   *con = (Const *) node;
+
+		/* Check for regclass reference */
+		if (ISREGCLASSCONST(con))
+			root->glob->relationOids =
+				lappend_oid(root->glob->relationOids,
+							DatumGetObjectId(con->constvalue));
+	}
+	else if (IsA(node, GroupingFunc))
+	{
+		GroupingFunc *g = (GroupingFunc *) node;
+		AttrNumber *grouping_map = root->grouping_map;
+
+		/* If there are no grouping sets, we don't need this. */
+
+		Assert(grouping_map || g->cols == NIL);
+
+		if (grouping_map)
+		{
+			ListCell   *lc;
+			List	   *cols = NIL;
+
+			foreach(lc, g->refs)
+			{
+				cols = lappend_int(cols, grouping_map[lfirst_int(lc)]);
+			}
+
+			Assert(!g->cols || equal(cols, g->cols));
+
+			if (!g->cols)
+				g->cols = cols;
+		}
+	}
+}
+
+/*
+ * fix_param_node
+ *		Do set_plan_references processing on a Param
+ *
+ * If it's a PARAM_MULTIEXPR, replace it with the appropriate Param from
+ * root->multiexpr_params; otherwise no change is needed.
+ * Just for paranoia's sake, we make a copy of the node in either case.
+ */
+static Node *
+fix_param_node(PlannerInfo *root, Param *p)
+{
+	if (p->paramkind == PARAM_MULTIEXPR)
+	{
+		int			subqueryid = p->paramid >> 16;
+		int			colno = p->paramid & 0xFFFF;
+		List	   *params;
+
+		if (subqueryid <= 0 ||
+			subqueryid > list_length(root->multiexpr_params))
+			elog(ERROR, "unexpected PARAM_MULTIEXPR ID: %d", p->paramid);
+		params = (List *) list_nth(root->multiexpr_params, subqueryid - 1);
+		if (colno <= 0 || colno > list_length(params))
+			elog(ERROR, "unexpected PARAM_MULTIEXPR ID: %d", p->paramid);
+		return copyObject(list_nth(params, colno - 1));
+	}
+	return (Node *) copyObject(p);
+}
+
+/*
+ * fix_alternative_subplan
+ *		Do set_plan_references processing on an AlternativeSubPlan
+ *
+ * Choose one of the alternative implementations and return just that one,
+ * discarding the rest of the AlternativeSubPlan structure.
+ * Note: caller must still recurse into the result!
+ *
+ * We don't make any attempt to fix up cost estimates in the parent plan
+ * node or higher-level nodes.
+ */
+static Node *
+fix_alternative_subplan(PlannerInfo *root, AlternativeSubPlan *asplan,
+						double num_exec)
+{
+	SubPlan    *bestplan = NULL;
+	Cost		bestcost = 0;
+	ListCell   *lc;
+
+	/*
+	 * Compute the estimated cost of each subplan assuming num_exec
+	 * executions, and keep the cheapest one.  In event of exact equality of
+	 * estimates, we prefer the later plan; this is a bit arbitrary, but in
+	 * current usage it biases us to break ties against fast-start subplans.
+	 */
+	Assert(asplan->subplans != NIL);
+
+	foreach(lc, asplan->subplans)
+	{
+		SubPlan    *curplan = (SubPlan *) lfirst(lc);
+		Cost		curcost;
+
+		curcost = curplan->startup_cost + num_exec * curplan->per_call_cost;
+		if (bestplan == NULL || curcost <= bestcost)
+		{
+			bestplan = curplan;
+			bestcost = curcost;
+		}
+
+		/* Also mark all subplans that are in AlternativeSubPlans */
+		root->isAltSubplan[curplan->plan_id - 1] = true;
+	}
+
+	/* Mark the subplan we selected */
+	root->isUsedSubplan[bestplan->plan_id - 1] = true;
+
+	return (Node *) bestplan;
+}
+
+/*
+ * fix_scan_expr
+ *		Do set_plan_references processing on a scan-level expression
+ *
+ * This consists of incrementing all Vars' varnos by rtoffset,
+ * replacing PARAM_MULTIEXPR Params, expanding PlaceHolderVars,
+ * replacing Aggref nodes that should be replaced by initplan output Params,
+ * choosing the best implementation for AlternativeSubPlans,
+ * looking up operator opcode info for OpExpr and related nodes,
+ * and adding OIDs from regclass Const nodes into root->glob->relationOids.
+ *
+ * 'node': the expression to be modified
+ * 'rtoffset': how much to increment varnos by
+ * 'num_exec': estimated number of executions of expression
+ *
+ * The expression tree is either copied-and-modified, or modified in-place
+ * if that seems safe.
+ */
+static Node *
+fix_scan_expr(PlannerInfo *root, Node *node, int rtoffset, double num_exec)
+{
+	fix_scan_expr_context context;
+
+	context.root = root;
+	context.rtoffset = rtoffset;
+	context.num_exec = num_exec;
+
+	if (rtoffset != 0 ||
+		root->multiexpr_params != NIL ||
+		root->glob->lastPHId != 0 ||
+		root->minmax_aggs != NIL ||
+		root->hasAlternativeSubPlans)
+	{
+		return fix_scan_expr_mutator(node, &context);
+	}
+	else
+	{
+		/*
+		 * If rtoffset == 0, we don't need to change any Vars, and if there
+		 * are no MULTIEXPR subqueries then we don't need to replace
+		 * PARAM_MULTIEXPR Params, and if there are no placeholders anywhere
+		 * we won't need to remove them, and if there are no minmax Aggrefs we
+		 * won't need to replace them, and if there are no AlternativeSubPlans
+		 * we won't need to remove them.  Then it's OK to just scribble on the
+		 * input node tree instead of copying (since the only change, filling
+		 * in any unset opfuncid fields, is harmless).  This saves just enough
+		 * cycles to be noticeable on trivial queries.
+		 */
+		(void) fix_scan_expr_walker(node, &context);
+		return node;
+	}
+}
+
+static Node *
+fix_scan_expr_mutator(Node *node, fix_scan_expr_context *context)
+{
+	if (node == NULL)
+		return NULL;
+	if (IsA(node, Var))
+	{
+		Var		   *var = copyVar((Var *) node);
+
+		Assert(var->varlevelsup == 0);
+
+		/*
+		 * We should not see Vars marked INNER_VAR, OUTER_VAR, or ROWID_VAR.
+		 * But an indexqual expression could contain INDEX_VAR Vars.
+		 */
+		Assert(var->varno != INNER_VAR);
+		Assert(var->varno != OUTER_VAR);
+		Assert(var->varno != ROWID_VAR);
+		if (!IS_SPECIAL_VARNO(var->varno))
+			var->varno += context->rtoffset;
+		if (var->varnosyn > 0)
+			var->varnosyn += context->rtoffset;
+		return (Node *) var;
+	}
+	if (IsA(node, Param))
+		return fix_param_node(context->root, (Param *) node);
+	if (IsA(node, Aggref))
+	{
+		Aggref	   *aggref = (Aggref *) node;
+
+		/* See if the Aggref should be replaced by a Param */
+		if (context->root->minmax_aggs != NIL &&
+			list_length(aggref->args) == 1)
+		{
+			TargetEntry *curTarget = (TargetEntry *) linitial(aggref->args);
+			ListCell   *lc;
+
+			foreach(lc, context->root->minmax_aggs)
+			{
+				MinMaxAggInfo *mminfo = (MinMaxAggInfo *) lfirst(lc);
+
+				if (mminfo->aggfnoid == aggref->aggfnoid &&
+					equal(mminfo->target, curTarget->expr))
+					return (Node *) copyObject(mminfo->param);
+			}
+		}
+		/* If no match, just fall through to process it normally */
+	}
+	if (IsA(node, CurrentOfExpr))
+	{
+		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;
+		return (Node *) cexpr;
+	}
+	if (IsA(node, PlaceHolderVar))
+	{
+		/* At scan level, we should always just evaluate the contained expr */
+		PlaceHolderVar *phv = (PlaceHolderVar *) node;
+
+		return fix_scan_expr_mutator((Node *) phv->phexpr, context);
+	}
+	if (IsA(node, AlternativeSubPlan))
+		return fix_scan_expr_mutator(fix_alternative_subplan(context->root,
+															 (AlternativeSubPlan *) node,
+															 context->num_exec),
+									 context);
+	fix_expr_common(context->root, node);
+	return expression_tree_mutator(node, fix_scan_expr_mutator,
+								   (void *) context);
+}
+
+static bool
+fix_scan_expr_walker(Node *node, fix_scan_expr_context *context)
+{
+	if (node == NULL)
+		return false;
+	Assert(!(IsA(node, Var) && ((Var *) node)->varno == ROWID_VAR));
+	Assert(!IsA(node, PlaceHolderVar));
+	Assert(!IsA(node, AlternativeSubPlan));
+	fix_expr_common(context->root, node);
+	return expression_tree_walker(node, fix_scan_expr_walker,
+								  (void *) context);
+}
+
+/*
+ * set_join_references
+ *	  Modify the target list and quals of a join node to reference its
+ *	  subplans, by setting the varnos to OUTER_VAR or INNER_VAR and setting
+ *	  attno values to the result domain number of either the corresponding
+ *	  outer or inner join tuple item.  Also perform opcode lookup for these
+ *	  expressions, and add regclass OIDs to root->glob->relationOids.
+ */
+static void
+set_join_references(PlannerInfo *root, Join *join, int rtoffset)
+{
+	Plan	   *outer_plan = join->plan.lefttree;
+	Plan	   *inner_plan = join->plan.righttree;
+	indexed_tlist *outer_itlist;
+	indexed_tlist *inner_itlist;
+
+	outer_itlist = build_tlist_index(outer_plan->targetlist);
+	inner_itlist = build_tlist_index(inner_plan->targetlist);
+
+	/*
+	 * First process the joinquals (including merge or hash clauses).  These
+	 * are logically below the join so they can always use all values
+	 * available from the input tlists.  It's okay to also handle
+	 * NestLoopParams now, because those couldn't refer to nullable
+	 * subexpressions.
+	 */
+	join->joinqual = fix_join_expr(root,
+								   join->joinqual,
+								   outer_itlist,
+								   inner_itlist,
+								   (Index) 0,
+								   rtoffset,
+								   NUM_EXEC_QUAL((Plan *) join));
+
+	/* Now do join-type-specific stuff */
+	if (IsA(join, NestLoop))
+	{
+		NestLoop   *nl = (NestLoop *) join;
+		ListCell   *lc;
+
+		foreach(lc, nl->nestParams)
+		{
+			NestLoopParam *nlp = (NestLoopParam *) lfirst(lc);
+
+			nlp->paramval = (Var *) fix_upper_expr(root,
+												   (Node *) nlp->paramval,
+												   outer_itlist,
+												   OUTER_VAR,
+												   rtoffset,
+												   NUM_EXEC_TLIST(outer_plan));
+			/* Check we replaced any PlaceHolderVar with simple Var */
+			if (!(IsA(nlp->paramval, Var) &&
+				  nlp->paramval->varno == OUTER_VAR))
+				elog(ERROR, "NestLoopParam was not reduced to a simple Var");
+		}
+	}
+	else if (IsA(join, MergeJoin))
+	{
+		MergeJoin  *mj = (MergeJoin *) join;
+
+		mj->mergeclauses = fix_join_expr(root,
+										 mj->mergeclauses,
+										 outer_itlist,
+										 inner_itlist,
+										 (Index) 0,
+										 rtoffset,
+										 NUM_EXEC_QUAL((Plan *) join));
+	}
+	else if (IsA(join, HashJoin))
+	{
+		HashJoin   *hj = (HashJoin *) join;
+
+		hj->hashclauses = fix_join_expr(root,
+										hj->hashclauses,
+										outer_itlist,
+										inner_itlist,
+										(Index) 0,
+										rtoffset,
+										NUM_EXEC_QUAL((Plan *) join));
+
+		/*
+		 * HashJoin's hashkeys are used to look for matching tuples from its
+		 * outer plan (not the Hash node!) in the hashtable.
+		 */
+		hj->hashkeys = (List *) fix_upper_expr(root,
+											   (Node *) hj->hashkeys,
+											   outer_itlist,
+											   OUTER_VAR,
+											   rtoffset,
+											   NUM_EXEC_QUAL((Plan *) join));
+	}
+
+	/*
+	 * Now we need to fix up the targetlist and qpqual, which are logically
+	 * above the join.  This means they should not re-use any input expression
+	 * that was computed in the nullable side of an outer join.  Vars and
+	 * PlaceHolderVars are fine, so we can implement this restriction just by
+	 * clearing has_non_vars in the indexed_tlist structs.
+	 *
+	 * XXX This is a grotty workaround for the fact that we don't clearly
+	 * distinguish between a Var appearing below an outer join and the "same"
+	 * Var appearing above it.  If we did, we'd not need to hack the matching
+	 * rules this way.
+	 */
+	switch (join->jointype)
+	{
+		case JOIN_LEFT:
+		case JOIN_SEMI:
+		case JOIN_ANTI:
+			inner_itlist->has_non_vars = false;
+			break;
+		case JOIN_RIGHT:
+			outer_itlist->has_non_vars = false;
+			break;
+		case JOIN_FULL:
+			outer_itlist->has_non_vars = false;
+			inner_itlist->has_non_vars = false;
+			break;
+		default:
+			break;
+	}
+
+	join->plan.targetlist = fix_join_expr(root,
+										  join->plan.targetlist,
+										  outer_itlist,
+										  inner_itlist,
+										  (Index) 0,
+										  rtoffset,
+										  NUM_EXEC_TLIST((Plan *) join));
+	join->plan.qual = fix_join_expr(root,
+									join->plan.qual,
+									outer_itlist,
+									inner_itlist,
+									(Index) 0,
+									rtoffset,
+									NUM_EXEC_QUAL((Plan *) join));
+
+	pfree(outer_itlist);
+	pfree(inner_itlist);
+}
+
+/*
+ * set_upper_references
+ *	  Update the targetlist and quals of an upper-level plan node
+ *	  to refer to the tuples returned by its lefttree subplan.
+ *	  Also perform opcode lookup for these expressions, and
+ *	  add regclass OIDs to root->glob->relationOids.
+ *
+ * This is used for single-input plan types like Agg, Group, Result.
+ *
+ * In most cases, we have to match up individual Vars in the tlist and
+ * qual expressions with elements of the subplan's tlist (which was
+ * generated by flattening these selfsame expressions, so it should have all
+ * the required variables).  There is an important exception, however:
+ * depending on where we are in the plan tree, sort/group columns may have
+ * been pushed into the subplan tlist unflattened.  If these values are also
+ * needed in the output then we want to reference the subplan tlist element
+ * rather than recomputing the expression.
+ */
+static void
+set_upper_references(PlannerInfo *root, Plan *plan, int rtoffset)
+{
+	Plan	   *subplan = plan->lefttree;
+	indexed_tlist *subplan_itlist;
+	List	   *output_targetlist;
+	ListCell   *l;
+
+	subplan_itlist = build_tlist_index(subplan->targetlist);
+
+	output_targetlist = NIL;
+	foreach(l, plan->targetlist)
+	{
+		TargetEntry *tle = (TargetEntry *) lfirst(l);
+		Node	   *newexpr;
+
+		/* If it's a sort/group item, first try to match by sortref */
+		if (tle->ressortgroupref != 0)
+		{
+			newexpr = (Node *)
+				search_indexed_tlist_for_sortgroupref(tle->expr,
+													  tle->ressortgroupref,
+													  subplan_itlist,
+													  OUTER_VAR);
+			if (!newexpr)
+				newexpr = fix_upper_expr(root,
+										 (Node *) tle->expr,
+										 subplan_itlist,
+										 OUTER_VAR,
+										 rtoffset,
+										 NUM_EXEC_TLIST(plan));
+		}
+		else
+			newexpr = fix_upper_expr(root,
+									 (Node *) tle->expr,
+									 subplan_itlist,
+									 OUTER_VAR,
+									 rtoffset,
+									 NUM_EXEC_TLIST(plan));
+		tle = flatCopyTargetEntry(tle);
+		tle->expr = (Expr *) newexpr;
+		output_targetlist = lappend(output_targetlist, tle);
+	}
+	plan->targetlist = output_targetlist;
+
+	plan->qual = (List *)
+		fix_upper_expr(root,
+					   (Node *) plan->qual,
+					   subplan_itlist,
+					   OUTER_VAR,
+					   rtoffset,
+					   NUM_EXEC_QUAL(plan));
+
+	pfree(subplan_itlist);
+}
+
+/*
+ * set_param_references
+ *	  Initialize the initParam list in Gather or Gather merge node such that
+ *	  it contains reference of all the params that needs to be evaluated
+ *	  before execution of the node.  It contains the initplan params that are
+ *	  being passed to the plan nodes below it.
+ */
+static void
+set_param_references(PlannerInfo *root, Plan *plan)
+{
+	Assert(IsA(plan, Gather) || IsA(plan, GatherMerge));
+
+	if (plan->lefttree->extParam)
+	{
+		PlannerInfo *proot;
+		Bitmapset  *initSetParam = NULL;
+		ListCell   *l;
+
+		for (proot = root; proot != NULL; proot = proot->parent_root)
+		{
+			foreach(l, proot->init_plans)
+			{
+				SubPlan    *initsubplan = (SubPlan *) lfirst(l);
+				ListCell   *l2;
+
+				foreach(l2, initsubplan->setParam)
+				{
+					initSetParam = bms_add_member(initSetParam, lfirst_int(l2));
+				}
+			}
+		}
+
+		/*
+		 * Remember the list of all external initplan params that are used by
+		 * the children of Gather or Gather merge node.
+		 */
+		if (IsA(plan, Gather))
+			((Gather *) plan)->initParam =
+				bms_intersect(plan->lefttree->extParam, initSetParam);
+		else
+			((GatherMerge *) plan)->initParam =
+				bms_intersect(plan->lefttree->extParam, initSetParam);
+	}
+}
+
+/*
+ * Recursively scan an expression tree and convert Aggrefs to the proper
+ * intermediate form for combining aggregates.  This means (1) replacing each
+ * one's argument list with a single argument that is the original Aggref
+ * modified to show partial aggregation and (2) changing the upper Aggref to
+ * show combining aggregation.
+ *
+ * After this step, set_upper_references will replace the partial Aggrefs
+ * with Vars referencing the lower Agg plan node's outputs, so that the final
+ * form seen by the executor is a combining Aggref with a Var as input.
+ *
+ * It's rather messy to postpone this step until setrefs.c; ideally it'd be
+ * done in createplan.c.  The difficulty is that once we modify the Aggref
+ * expressions, they will no longer be equal() to their original form and
+ * so cross-plan-node-level matches will fail.  So this has to happen after
+ * the plan node above the Agg has resolved its subplan references.
+ */
+static Node *
+convert_combining_aggrefs(Node *node, void *context)
+{
+	if (node == NULL)
+		return NULL;
+	if (IsA(node, Aggref))
+	{
+		Aggref	   *orig_agg = (Aggref *) node;
+		Aggref	   *child_agg;
+		Aggref	   *parent_agg;
+
+		/* Assert we've not chosen to partial-ize any unsupported cases */
+		Assert(orig_agg->aggorder == NIL);
+		Assert(orig_agg->aggdistinct == NIL);
+
+		/*
+		 * Since aggregate calls can't be nested, we needn't recurse into the
+		 * arguments.  But for safety, flat-copy the Aggref node itself rather
+		 * than modifying it in-place.
+		 */
+		child_agg = makeNode(Aggref);
+		memcpy(child_agg, orig_agg, sizeof(Aggref));
+
+		/*
+		 * For the parent Aggref, we want to copy all the fields of the
+		 * original aggregate *except* the args list, which we'll replace
+		 * below, and the aggfilter expression, which should be applied only
+		 * by the child not the parent.  Rather than explicitly knowing about
+		 * all the other fields here, we can momentarily modify child_agg to
+		 * provide a suitable source for copyObject.
+		 */
+		child_agg->args = NIL;
+		child_agg->aggfilter = NULL;
+		parent_agg = copyObject(child_agg);
+		child_agg->args = orig_agg->args;
+		child_agg->aggfilter = orig_agg->aggfilter;
+
+		/*
+		 * Now, set up child_agg to represent the first phase of partial
+		 * aggregation.  For now, assume serialization is required.
+		 */
+		mark_partial_aggref(child_agg, AGGSPLIT_INITIAL_SERIAL);
+
+		/*
+		 * And set up parent_agg to represent the second phase.
+		 */
+		parent_agg->args = list_make1(makeTargetEntry((Expr *) child_agg,
+													  1, NULL, false));
+		mark_partial_aggref(parent_agg, AGGSPLIT_FINAL_DESERIAL);
+
+		return (Node *) parent_agg;
+	}
+	return expression_tree_mutator(node, convert_combining_aggrefs,
+								   (void *) context);
+}
+
+/*
+ * set_dummy_tlist_references
+ *	  Replace the targetlist of an upper-level plan node with a simple
+ *	  list of OUTER_VAR references to its child.
+ *
+ * This is used for plan types like Sort and Append that don't evaluate
+ * their targetlists.  Although the executor doesn't care at all what's in
+ * the tlist, EXPLAIN needs it to be realistic.
+ *
+ * Note: we could almost use set_upper_references() here, but it fails for
+ * Append for lack of a lefttree subplan.  Single-purpose code is faster
+ * anyway.
+ */
+static void
+set_dummy_tlist_references(Plan *plan, int rtoffset)
+{
+	List	   *output_targetlist;
+	ListCell   *l;
+
+	output_targetlist = NIL;
+	foreach(l, plan->targetlist)
+	{
+		TargetEntry *tle = (TargetEntry *) lfirst(l);
+		Var		   *oldvar = (Var *) tle->expr;
+		Var		   *newvar;
+
+		/*
+		 * As in search_indexed_tlist_for_non_var(), we prefer to keep Consts
+		 * as Consts, not Vars referencing Consts.  Here, there's no speed
+		 * advantage to be had, but it makes EXPLAIN output look cleaner, and
+		 * again it avoids confusing the executor.
+		 */
+		if (IsA(oldvar, Const))
+		{
+			/* just reuse the existing TLE node */
+			output_targetlist = lappend(output_targetlist, tle);
+			continue;
+		}
+
+		newvar = makeVar(OUTER_VAR,
+						 tle->resno,
+						 exprType((Node *) oldvar),
+						 exprTypmod((Node *) oldvar),
+						 exprCollation((Node *) oldvar),
+						 0);
+		if (IsA(oldvar, Var) &&
+			oldvar->varnosyn > 0)
+		{
+			newvar->varnosyn = oldvar->varnosyn + rtoffset;
+			newvar->varattnosyn = oldvar->varattnosyn;
+		}
+		else
+		{
+			newvar->varnosyn = 0;	/* wasn't ever a plain Var */
+			newvar->varattnosyn = 0;
+		}
+
+		tle = flatCopyTargetEntry(tle);
+		tle->expr = (Expr *) newvar;
+		output_targetlist = lappend(output_targetlist, tle);
+	}
+	plan->targetlist = output_targetlist;
+
+	/* We don't touch plan->qual here */
+}
+
+
+/*
+ * build_tlist_index --- build an index data structure for a child tlist
+ *
+ * In most cases, subplan tlists will be "flat" tlists with only Vars,
+ * so we try to optimize that case by extracting information about Vars
+ * in advance.  Matching a parent tlist to a child is still an O(N^2)
+ * operation, but at least with a much smaller constant factor than plain
+ * tlist_member() searches.
+ *
+ * The result of this function is an indexed_tlist struct to pass to
+ * search_indexed_tlist_for_var() or search_indexed_tlist_for_non_var().
+ * When done, the indexed_tlist may be freed with a single pfree().
+ */
+static indexed_tlist *
+build_tlist_index(List *tlist)
+{
+	indexed_tlist *itlist;
+	tlist_vinfo *vinfo;
+	ListCell   *l;
+
+	/* Create data structure with enough slots for all tlist entries */
+	itlist = (indexed_tlist *)
+		palloc(offsetof(indexed_tlist, vars) +
+			   list_length(tlist) * sizeof(tlist_vinfo));
+
+	itlist->tlist = tlist;
+	itlist->has_ph_vars = false;
+	itlist->has_non_vars = false;
+
+	/* Find the Vars and fill in the index array */
+	vinfo = itlist->vars;
+	foreach(l, tlist)
+	{
+		TargetEntry *tle = (TargetEntry *) lfirst(l);
+
+		if (tle->expr && IsA(tle->expr, Var))
+		{
+			Var		   *var = (Var *) tle->expr;
+
+			vinfo->varno = var->varno;
+			vinfo->varattno = var->varattno;
+			vinfo->resno = tle->resno;
+			vinfo++;
+		}
+		else if (tle->expr && IsA(tle->expr, PlaceHolderVar))
+			itlist->has_ph_vars = true;
+		else
+			itlist->has_non_vars = true;
+	}
+
+	itlist->num_vars = (vinfo - itlist->vars);
+
+	return itlist;
+}
+
+/*
+ * build_tlist_index_other_vars --- build a restricted tlist index
+ *
+ * This is like build_tlist_index, but we only index tlist entries that
+ * are Vars belonging to some rel other than the one specified.  We will set
+ * has_ph_vars (allowing PlaceHolderVars to be matched), but not has_non_vars
+ * (so nothing other than Vars and PlaceHolderVars can be matched).
+ */
+static indexed_tlist *
+build_tlist_index_other_vars(List *tlist, Index ignore_rel)
+{
+	indexed_tlist *itlist;
+	tlist_vinfo *vinfo;
+	ListCell   *l;
+
+	/* Create data structure with enough slots for all tlist entries */
+	itlist = (indexed_tlist *)
+		palloc(offsetof(indexed_tlist, vars) +
+			   list_length(tlist) * sizeof(tlist_vinfo));
+
+	itlist->tlist = tlist;
+	itlist->has_ph_vars = false;
+	itlist->has_non_vars = false;
+
+	/* Find the desired Vars and fill in the index array */
+	vinfo = itlist->vars;
+	foreach(l, tlist)
+	{
+		TargetEntry *tle = (TargetEntry *) lfirst(l);
+
+		if (tle->expr && IsA(tle->expr, Var))
+		{
+			Var		   *var = (Var *) tle->expr;
+
+			if (var->varno != ignore_rel)
+			{
+				vinfo->varno = var->varno;
+				vinfo->varattno = var->varattno;
+				vinfo->resno = tle->resno;
+				vinfo++;
+			}
+		}
+		else if (tle->expr && IsA(tle->expr, PlaceHolderVar))
+			itlist->has_ph_vars = true;
+	}
+
+	itlist->num_vars = (vinfo - itlist->vars);
+
+	return itlist;
+}
+
+/*
+ * search_indexed_tlist_for_var --- find a Var in an indexed tlist
+ *
+ * If a match is found, return a copy of the given Var with suitably
+ * modified varno/varattno (to wit, newvarno and the resno of the TLE entry).
+ * Also ensure that varnosyn is incremented by rtoffset.
+ * If no match, return NULL.
+ */
+static Var *
+search_indexed_tlist_for_var(Var *var, indexed_tlist *itlist,
+							 Index newvarno, int rtoffset)
+{
+	Index		varno = var->varno;
+	AttrNumber	varattno = var->varattno;
+	tlist_vinfo *vinfo;
+	int			i;
+
+	vinfo = itlist->vars;
+	i = itlist->num_vars;
+	while (i-- > 0)
+	{
+		if (vinfo->varno == varno && vinfo->varattno == varattno)
+		{
+			/* Found a match */
+			Var		   *newvar = copyVar(var);
+
+			newvar->varno = newvarno;
+			newvar->varattno = vinfo->resno;
+			if (newvar->varnosyn > 0)
+				newvar->varnosyn += rtoffset;
+			return newvar;
+		}
+		vinfo++;
+	}
+	return NULL;				/* no match */
+}
+
+/*
+ * search_indexed_tlist_for_non_var --- find a non-Var in an indexed tlist
+ *
+ * If a match is found, return a Var constructed to reference the tlist item.
+ * If no match, return NULL.
+ *
+ * NOTE: it is a waste of time to call this unless itlist->has_ph_vars or
+ * itlist->has_non_vars.  Furthermore, set_join_references() relies on being
+ * able to prevent matching of non-Vars by clearing itlist->has_non_vars,
+ * so there's a correctness reason not to call it unless that's set.
+ */
+static Var *
+search_indexed_tlist_for_non_var(Expr *node,
+								 indexed_tlist *itlist, Index newvarno)
+{
+	TargetEntry *tle;
+
+	/*
+	 * If it's a simple Const, replacing it with a Var is silly, even if there
+	 * happens to be an identical Const below; a Var is more expensive to
+	 * execute than a Const.  What's more, replacing it could confuse some
+	 * places in the executor that expect to see simple Consts for, eg,
+	 * dropped columns.
+	 */
+	if (IsA(node, Const))
+		return NULL;
+
+	tle = tlist_member(node, itlist->tlist);
+	if (tle)
+	{
+		/* Found a matching subplan output expression */
+		Var		   *newvar;
+
+		newvar = makeVarFromTargetEntry(newvarno, tle);
+		newvar->varnosyn = 0;	/* wasn't ever a plain Var */
+		newvar->varattnosyn = 0;
+		return newvar;
+	}
+	return NULL;				/* no match */
+}
+
+/*
+ * search_indexed_tlist_for_sortgroupref --- find a sort/group expression
+ *
+ * If a match is found, return a Var constructed to reference the tlist item.
+ * If no match, return NULL.
+ *
+ * This is needed to ensure that we select the right subplan TLE in cases
+ * where there are multiple textually-equal()-but-volatile sort expressions.
+ * And it's also faster than search_indexed_tlist_for_non_var.
+ */
+static Var *
+search_indexed_tlist_for_sortgroupref(Expr *node,
+									  Index sortgroupref,
+									  indexed_tlist *itlist,
+									  Index newvarno)
+{
+	ListCell   *lc;
+
+	foreach(lc, itlist->tlist)
+	{
+		TargetEntry *tle = (TargetEntry *) lfirst(lc);
+
+		/* The equal() check should be redundant, but let's be paranoid */
+		if (tle->ressortgroupref == sortgroupref &&
+			equal(node, tle->expr))
+		{
+			/* Found a matching subplan output expression */
+			Var		   *newvar;
+
+			newvar = makeVarFromTargetEntry(newvarno, tle);
+			newvar->varnosyn = 0;	/* wasn't ever a plain Var */
+			newvar->varattnosyn = 0;
+			return newvar;
+		}
+	}
+	return NULL;				/* no match */
+}
+
+/*
+ * fix_join_expr
+ *	   Create a new set of targetlist entries or join qual clauses by
+ *	   changing the varno/varattno values of variables in the clauses
+ *	   to reference target list values from the outer and inner join
+ *	   relation target lists.  Also perform opcode lookup and add
+ *	   regclass OIDs to root->glob->relationOids.
+ *
+ * This is used in three different scenarios:
+ * 1) a normal join clause, where all the Vars in the clause *must* be
+ *	  replaced by OUTER_VAR or INNER_VAR references.  In this case
+ *	  acceptable_rel should be zero so that any failure to match a Var will be
+ *	  reported as an error.
+ * 2) RETURNING clauses, which may contain both Vars of the target relation
+ *	  and Vars of other relations. In this case we want to replace the
+ *	  other-relation Vars by OUTER_VAR references, while leaving target Vars
+ *	  alone. Thus inner_itlist = NULL and acceptable_rel = the ID of the
+ *	  target relation should be passed.
+ * 3) ON CONFLICT UPDATE SET/WHERE clauses.  Here references to EXCLUDED are
+ *	  to be replaced with INNER_VAR references, while leaving target Vars (the
+ *	  to-be-updated relation) alone. Correspondingly inner_itlist is to be
+ *	  EXCLUDED elements, outer_itlist = NULL and acceptable_rel the target
+ *	  relation.
+ *
+ * 'clauses' is the targetlist or list of join clauses
+ * 'outer_itlist' is the indexed target list of the outer join relation,
+ *		or NULL
+ * 'inner_itlist' is the indexed target list of the inner join relation,
+ *		or NULL
+ * 'acceptable_rel' is either zero or the rangetable index of a relation
+ *		whose Vars may appear in the clause without provoking an error
+ * 'rtoffset': how much to increment varnos by
+ * 'num_exec': estimated number of executions of expression
+ *
+ * Returns the new expression tree.  The original clause structure is
+ * not modified.
+ */
+static List *
+fix_join_expr(PlannerInfo *root,
+			  List *clauses,
+			  indexed_tlist *outer_itlist,
+			  indexed_tlist *inner_itlist,
+			  Index acceptable_rel,
+			  int rtoffset,
+			  double num_exec)
+{
+	fix_join_expr_context context;
+
+	context.root = root;
+	context.outer_itlist = outer_itlist;
+	context.inner_itlist = inner_itlist;
+	context.acceptable_rel = acceptable_rel;
+	context.rtoffset = rtoffset;
+	context.num_exec = num_exec;
+	return (List *) fix_join_expr_mutator((Node *) clauses, &context);
+}
+
+static Node *
+fix_join_expr_mutator(Node *node, fix_join_expr_context *context)
+{
+	Var		   *newvar;
+
+	if (node == NULL)
+		return NULL;
+	if (IsA(node, Var))
+	{
+		Var		   *var = (Var *) node;
+
+		/* Look for the var in the input tlists, first in the outer */
+		if (context->outer_itlist)
+		{
+			newvar = search_indexed_tlist_for_var(var,
+												  context->outer_itlist,
+												  OUTER_VAR,
+												  context->rtoffset);
+			if (newvar)
+				return (Node *) newvar;
+		}
+
+		/* then in the inner. */
+		if (context->inner_itlist)
+		{
+			newvar = search_indexed_tlist_for_var(var,
+												  context->inner_itlist,
+												  INNER_VAR,
+												  context->rtoffset);
+			if (newvar)
+				return (Node *) newvar;
+		}
+
+		/* If it's for acceptable_rel, adjust and return it */
+		if (var->varno == context->acceptable_rel)
+		{
+			var = copyVar(var);
+			var->varno += context->rtoffset;
+			if (var->varnosyn > 0)
+				var->varnosyn += context->rtoffset;
+			return (Node *) var;
+		}
+
+		/* No referent found for Var */
+		elog(ERROR, "variable not found in subplan target lists");
+	}
+	if (IsA(node, PlaceHolderVar))
+	{
+		PlaceHolderVar *phv = (PlaceHolderVar *) node;
+
+		/* See if the PlaceHolderVar has bubbled up from a lower plan node */
+		if (context->outer_itlist && context->outer_itlist->has_ph_vars)
+		{
+			newvar = search_indexed_tlist_for_non_var((Expr *) phv,
+													  context->outer_itlist,
+													  OUTER_VAR);
+			if (newvar)
+				return (Node *) newvar;
+		}
+		if (context->inner_itlist && context->inner_itlist->has_ph_vars)
+		{
+			newvar = search_indexed_tlist_for_non_var((Expr *) phv,
+													  context->inner_itlist,
+													  INNER_VAR);
+			if (newvar)
+				return (Node *) newvar;
+		}
+
+		/* If not supplied by input plans, evaluate the contained expr */
+		return fix_join_expr_mutator((Node *) phv->phexpr, context);
+	}
+	/* Try matching more complex expressions too, if tlists have any */
+	if (context->outer_itlist && context->outer_itlist->has_non_vars)
+	{
+		newvar = search_indexed_tlist_for_non_var((Expr *) node,
+												  context->outer_itlist,
+												  OUTER_VAR);
+		if (newvar)
+			return (Node *) newvar;
+	}
+	if (context->inner_itlist && context->inner_itlist->has_non_vars)
+	{
+		newvar = search_indexed_tlist_for_non_var((Expr *) node,
+												  context->inner_itlist,
+												  INNER_VAR);
+		if (newvar)
+			return (Node *) newvar;
+	}
+	/* Special cases (apply only AFTER failing to match to lower tlist) */
+	if (IsA(node, Param))
+		return fix_param_node(context->root, (Param *) node);
+	if (IsA(node, AlternativeSubPlan))
+		return fix_join_expr_mutator(fix_alternative_subplan(context->root,
+															 (AlternativeSubPlan *) node,
+															 context->num_exec),
+									 context);
+	fix_expr_common(context->root, node);
+	return expression_tree_mutator(node,
+								   fix_join_expr_mutator,
+								   (void *) context);
+}
+
+/*
+ * fix_upper_expr
+ *		Modifies an expression tree so that all Var nodes reference outputs
+ *		of a subplan.  Also looks for Aggref nodes that should be replaced
+ *		by initplan output Params.  Also performs opcode lookup, and adds
+ *		regclass OIDs to root->glob->relationOids.
+ *
+ * This is used to fix up target and qual expressions of non-join upper-level
+ * plan nodes, as well as index-only scan nodes.
+ *
+ * An error is raised if no matching var can be found in the subplan tlist
+ * --- so this routine should only be applied to nodes whose subplans'
+ * targetlists were generated by flattening the expressions used in the
+ * parent node.
+ *
+ * If itlist->has_non_vars is true, then we try to match whole subexpressions
+ * against elements of the subplan tlist, so that we can avoid recomputing
+ * expressions that were already computed by the subplan.  (This is relatively
+ * expensive, so we don't want to try it in the common case where the
+ * subplan tlist is just a flattened list of Vars.)
+ *
+ * 'node': the tree to be fixed (a target item or qual)
+ * 'subplan_itlist': indexed target list for subplan (or index)
+ * 'newvarno': varno to use for Vars referencing tlist elements
+ * 'rtoffset': how much to increment varnos by
+ * 'num_exec': estimated number of executions of expression
+ *
+ * The resulting tree is a copy of the original in which all Var nodes have
+ * varno = newvarno, varattno = resno of corresponding targetlist element.
+ * The original tree is not modified.
+ */
+static Node *
+fix_upper_expr(PlannerInfo *root,
+			   Node *node,
+			   indexed_tlist *subplan_itlist,
+			   Index newvarno,
+			   int rtoffset,
+			   double num_exec)
+{
+	fix_upper_expr_context context;
+
+	context.root = root;
+	context.subplan_itlist = subplan_itlist;
+	context.newvarno = newvarno;
+	context.rtoffset = rtoffset;
+	context.num_exec = num_exec;
+	return fix_upper_expr_mutator(node, &context);
+}
+
+static Node *
+fix_upper_expr_mutator(Node *node, fix_upper_expr_context *context)
+{
+	Var		   *newvar;
+
+	if (node == NULL)
+		return NULL;
+	if (IsA(node, Var))
+	{
+		Var		   *var = (Var *) node;
+
+		newvar = search_indexed_tlist_for_var(var,
+											  context->subplan_itlist,
+											  context->newvarno,
+											  context->rtoffset);
+		if (!newvar)
+			elog(ERROR, "variable not found in subplan target list");
+		return (Node *) newvar;
+	}
+	if (IsA(node, PlaceHolderVar))
+	{
+		PlaceHolderVar *phv = (PlaceHolderVar *) node;
+
+		/* See if the PlaceHolderVar has bubbled up from a lower plan node */
+		if (context->subplan_itlist->has_ph_vars)
+		{
+			newvar = search_indexed_tlist_for_non_var((Expr *) phv,
+													  context->subplan_itlist,
+													  context->newvarno);
+			if (newvar)
+				return (Node *) newvar;
+		}
+		/* If not supplied by input plan, evaluate the contained expr */
+		return fix_upper_expr_mutator((Node *) phv->phexpr, context);
+	}
+	/* Try matching more complex expressions too, if tlist has any */
+	if (context->subplan_itlist->has_non_vars)
+	{
+		newvar = search_indexed_tlist_for_non_var((Expr *) node,
+												  context->subplan_itlist,
+												  context->newvarno);
+		if (newvar)
+			return (Node *) newvar;
+	}
+	/* Special cases (apply only AFTER failing to match to lower tlist) */
+	if (IsA(node, Param))
+		return fix_param_node(context->root, (Param *) node);
+	if (IsA(node, Aggref))
+	{
+		Aggref	   *aggref = (Aggref *) node;
+
+		/* See if the Aggref should be replaced by a Param */
+		if (context->root->minmax_aggs != NIL &&
+			list_length(aggref->args) == 1)
+		{
+			TargetEntry *curTarget = (TargetEntry *) linitial(aggref->args);
+			ListCell   *lc;
+
+			foreach(lc, context->root->minmax_aggs)
+			{
+				MinMaxAggInfo *mminfo = (MinMaxAggInfo *) lfirst(lc);
+
+				if (mminfo->aggfnoid == aggref->aggfnoid &&
+					equal(mminfo->target, curTarget->expr))
+					return (Node *) copyObject(mminfo->param);
+			}
+		}
+		/* If no match, just fall through to process it normally */
+	}
+	if (IsA(node, AlternativeSubPlan))
+		return fix_upper_expr_mutator(fix_alternative_subplan(context->root,
+															  (AlternativeSubPlan *) node,
+															  context->num_exec),
+									  context);
+	fix_expr_common(context->root, node);
+	return expression_tree_mutator(node,
+								   fix_upper_expr_mutator,
+								   (void *) context);
+}
+
+/*
+ * set_returning_clause_references
+ *		Perform setrefs.c's work on a RETURNING targetlist
+ *
+ * If the query involves more than just the result table, we have to
+ * adjust any Vars that refer to other tables to reference junk tlist
+ * entries in the top subplan's targetlist.  Vars referencing the result
+ * table should be left alone, however (the executor will evaluate them
+ * using the actual heap tuple, after firing triggers if any).  In the
+ * adjusted RETURNING list, result-table Vars will have their original
+ * varno (plus rtoffset), but Vars for other rels will have varno OUTER_VAR.
+ *
+ * We also must perform opcode lookup and add regclass OIDs to
+ * root->glob->relationOids.
+ *
+ * 'rlist': the RETURNING targetlist to be fixed
+ * 'topplan': the top subplan node that will be just below the ModifyTable
+ *		node (note it's not yet passed through set_plan_refs)
+ * 'resultRelation': RT index of the associated result relation
+ * 'rtoffset': how much to increment varnos by
+ *
+ * Note: the given 'root' is for the parent query level, not the 'topplan'.
+ * This does not matter currently since we only access the dependency-item
+ * lists in root->glob, but it would need some hacking if we wanted a root
+ * that actually matches the subplan.
+ *
+ * Note: resultRelation is not yet adjusted by rtoffset.
+ */
+static List *
+set_returning_clause_references(PlannerInfo *root,
+								List *rlist,
+								Plan *topplan,
+								Index resultRelation,
+								int rtoffset)
+{
+	indexed_tlist *itlist;
+
+	/*
+	 * We can perform the desired Var fixup by abusing the fix_join_expr
+	 * machinery that formerly handled inner indexscan fixup.  We search the
+	 * top plan's targetlist for Vars of non-result relations, and use
+	 * fix_join_expr to convert RETURNING Vars into references to those tlist
+	 * entries, while leaving result-rel Vars as-is.
+	 *
+	 * PlaceHolderVars will also be sought in the targetlist, but no
+	 * more-complex expressions will be.  Note that it is not possible for a
+	 * PlaceHolderVar to refer to the result relation, since the result is
+	 * never below an outer join.  If that case could happen, we'd have to be
+	 * prepared to pick apart the PlaceHolderVar and evaluate its contained
+	 * expression instead.
+	 */
+	itlist = build_tlist_index_other_vars(topplan->targetlist, resultRelation);
+
+	rlist = fix_join_expr(root,
+						  rlist,
+						  itlist,
+						  NULL,
+						  resultRelation,
+						  rtoffset,
+						  NUM_EXEC_TLIST(topplan));
+
+	pfree(itlist);
+
+	return rlist;
+}
+
+
+/*****************************************************************************
+ *					QUERY DEPENDENCY MANAGEMENT
+ *****************************************************************************/
+
+/*
+ * record_plan_function_dependency
+ *		Mark the current plan as depending on a particular function.
+ *
+ * This is exported so that the function-inlining code can record a
+ * dependency on a function that it's removed from the plan tree.
+ */
+void
+record_plan_function_dependency(PlannerInfo *root, Oid funcid)
+{
+	/*
+	 * For performance reasons, we don't bother to track built-in functions;
+	 * we just assume they'll never change (or at least not in ways that'd
+	 * invalidate plans using them).  For this purpose we can consider a
+	 * built-in function to be one with OID less than FirstBootstrapObjectId.
+	 * Note that the OID generator guarantees never to generate such an OID
+	 * after startup, even at OID wraparound.
+	 */
+	if (funcid >= (Oid) FirstBootstrapObjectId)
+	{
+		PlanInvalItem *inval_item = makeNode(PlanInvalItem);
+
+		/*
+		 * It would work to use any syscache on pg_proc, but the easiest is
+		 * PROCOID since we already have the function's OID at hand.  Note
+		 * that plancache.c knows we use PROCOID.
+		 */
+		inval_item->cacheId = PROCOID;
+		inval_item->hashValue = GetSysCacheHashValue1(PROCOID,
+													  ObjectIdGetDatum(funcid));
+
+		root->glob->invalItems = lappend(root->glob->invalItems, inval_item);
+	}
+}
+
+/*
+ * record_plan_type_dependency
+ *		Mark the current plan as depending on a particular type.
+ *
+ * This is exported so that eval_const_expressions can record a
+ * dependency on a domain that it's removed a CoerceToDomain node for.
+ *
+ * We don't currently need to record dependencies on domains that the
+ * plan contains CoerceToDomain nodes for, though that might change in
+ * future.  Hence, this isn't actually called in this module, though
+ * someday fix_expr_common might call it.
+ */
+void
+record_plan_type_dependency(PlannerInfo *root, Oid typid)
+{
+	/*
+	 * As in record_plan_function_dependency, ignore the possibility that
+	 * someone would change a built-in domain.
+	 */
+	if (typid >= (Oid) FirstBootstrapObjectId)
+	{
+		PlanInvalItem *inval_item = makeNode(PlanInvalItem);
+
+		/*
+		 * It would work to use any syscache on pg_type, but the easiest is
+		 * TYPEOID since we already have the type's OID at hand.  Note that
+		 * plancache.c knows we use TYPEOID.
+		 */
+		inval_item->cacheId = TYPEOID;
+		inval_item->hashValue = GetSysCacheHashValue1(TYPEOID,
+													  ObjectIdGetDatum(typid));
+
+		root->glob->invalItems = lappend(root->glob->invalItems, inval_item);
+	}
+}
+
+/*
+ * extract_query_dependencies
+ *		Given a rewritten, but not yet planned, query or queries
+ *		(i.e. a Query node or list of Query nodes), extract dependencies
+ *		just as set_plan_references would do.  Also detect whether any
+ *		rewrite steps were affected by RLS.
+ *
+ * This is needed by plancache.c to handle invalidation of cached unplanned
+ * queries.
+ *
+ * Note: this does not go through eval_const_expressions, and hence doesn't
+ * reflect its additions of inlined functions and elided CoerceToDomain nodes
+ * to the invalItems list.  This is obviously OK for functions, since we'll
+ * see them in the original query tree anyway.  For domains, it's OK because
+ * we don't care about domains unless they get elided.  That is, a plan might
+ * have domain dependencies that the query tree doesn't.
+ */
+void
+extract_query_dependencies(Node *query,
+						   List **relationOids,
+						   List **invalItems,
+						   bool *hasRowSecurity)
+{
+	PlannerGlobal glob;
+	PlannerInfo root;
+
+	/* Make up dummy planner state so we can use this module's machinery */
+	MemSet(&glob, 0, sizeof(glob));
+	glob.type = T_PlannerGlobal;
+	glob.relationOids = NIL;
+	glob.invalItems = NIL;
+	/* Hack: we use glob.dependsOnRole to collect hasRowSecurity flags */
+	glob.dependsOnRole = false;
+
+	MemSet(&root, 0, sizeof(root));
+	root.type = T_PlannerInfo;
+	root.glob = &glob;
+
+	(void) extract_query_dependencies_walker(query, &root);
+
+	*relationOids = glob.relationOids;
+	*invalItems = glob.invalItems;
+	*hasRowSecurity = glob.dependsOnRole;
+}
+
+/*
+ * Tree walker for extract_query_dependencies.
+ *
+ * This is exported so that expression_planner_with_deps can call it on
+ * simple expressions (post-planning, not before planning, in that case).
+ * In that usage, glob.dependsOnRole isn't meaningful, but the relationOids
+ * and invalItems lists are added to as needed.
+ */
+bool
+extract_query_dependencies_walker(Node *node, PlannerInfo *context)
+{
+	if (node == NULL)
+		return false;
+	Assert(!IsA(node, PlaceHolderVar));
+	if (IsA(node, Query))
+	{
+		Query	   *query = (Query *) node;
+		ListCell   *lc;
+
+		if (query->commandType == CMD_UTILITY)
+		{
+			/*
+			 * Ignore utility statements, except those (such as EXPLAIN) that
+			 * contain a parsed-but-not-planned query.
+			 */
+			query = UtilityContainsQuery(query->utilityStmt);
+			if (query == NULL)
+				return false;
+		}
+
+		/* Remember if any Query has RLS quals applied by rewriter */
+		if (query->hasRowSecurity)
+			context->glob->dependsOnRole = true;
+
+		/* Collect relation OIDs in this Query's rtable */
+		foreach(lc, query->rtable)
+		{
+			RangeTblEntry *rte = (RangeTblEntry *) lfirst(lc);
+
+			if (rte->rtekind == RTE_RELATION)
+				context->glob->relationOids =
+					lappend_oid(context->glob->relationOids, rte->relid);
+			else if (rte->rtekind == RTE_NAMEDTUPLESTORE &&
+					 OidIsValid(rte->relid))
+				context->glob->relationOids =
+					lappend_oid(context->glob->relationOids,
+								rte->relid);
+		}
+
+		/* And recurse into the query's subexpressions */
+		return query_tree_walker(query, extract_query_dependencies_walker,
+								 (void *) context, 0);
+	}
+	/* Extract function dependencies and check for regclass Consts */
+	fix_expr_common(context, node);
+	return expression_tree_walker(node, extract_query_dependencies_walker,
+								  (void *) context);
+}