Adding upstream version 14.5.upstream/14.5upstream

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

1 files changed, 2993 insertions, 0 deletions

diff --git a/src/backend/optimizer/plan/subselect.c b/src/backend/optimizer/plan/subselect.c
new file mode 100644
index 0000000..0ee36b9
--- /dev/null
+++ b/src/backend/optimizer/plan/subselect.c
@@ -0,0 +1,2993 @@
+/*-------------------------------------------------------------------------
+ *
+ * subselect.c
+ *	  Planning routines for subselects.
+ *
+ * This module deals with SubLinks and CTEs, but not subquery RTEs (i.e.,
+ * not sub-SELECT-in-FROM cases).
+ *
+ * Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * IDENTIFICATION
+ *	  src/backend/optimizer/plan/subselect.c
+ *
+ *-------------------------------------------------------------------------
+ */
+#include "postgres.h"
+
+#include "access/htup_details.h"
+#include "catalog/pg_operator.h"
+#include "catalog/pg_type.h"
+#include "executor/executor.h"
+#include "miscadmin.h"
+#include "nodes/makefuncs.h"
+#include "nodes/nodeFuncs.h"
+#include "optimizer/clauses.h"
+#include "optimizer/cost.h"
+#include "optimizer/optimizer.h"
+#include "optimizer/paramassign.h"
+#include "optimizer/pathnode.h"
+#include "optimizer/planmain.h"
+#include "optimizer/planner.h"
+#include "optimizer/prep.h"
+#include "optimizer/subselect.h"
+#include "parser/parse_relation.h"
+#include "rewrite/rewriteManip.h"
+#include "utils/builtins.h"
+#include "utils/lsyscache.h"
+#include "utils/syscache.h"
+
+
+typedef struct convert_testexpr_context
+{
+	PlannerInfo *root;
+	List	   *subst_nodes;	/* Nodes to substitute for Params */
+} convert_testexpr_context;
+
+typedef struct process_sublinks_context
+{
+	PlannerInfo *root;
+	bool		isTopQual;
+} process_sublinks_context;
+
+typedef struct finalize_primnode_context
+{
+	PlannerInfo *root;
+	Bitmapset  *paramids;		/* Non-local PARAM_EXEC paramids found */
+} finalize_primnode_context;
+
+typedef struct inline_cte_walker_context
+{
+	const char *ctename;		/* name and relative level of target CTE */
+	int			levelsup;
+	Query	   *ctequery;		/* query to substitute */
+} inline_cte_walker_context;
+
+
+static Node *build_subplan(PlannerInfo *root, Plan *plan, PlannerInfo *subroot,
+						   List *plan_params,
+						   SubLinkType subLinkType, int subLinkId,
+						   Node *testexpr, List *testexpr_paramids,
+						   bool unknownEqFalse);
+static List *generate_subquery_params(PlannerInfo *root, List *tlist,
+									  List **paramIds);
+static List *generate_subquery_vars(PlannerInfo *root, List *tlist,
+									Index varno);
+static Node *convert_testexpr(PlannerInfo *root,
+							  Node *testexpr,
+							  List *subst_nodes);
+static Node *convert_testexpr_mutator(Node *node,
+									  convert_testexpr_context *context);
+static bool subplan_is_hashable(Plan *plan);
+static bool subpath_is_hashable(Path *path);
+static bool testexpr_is_hashable(Node *testexpr, List *param_ids);
+static bool test_opexpr_is_hashable(OpExpr *testexpr, List *param_ids);
+static bool hash_ok_operator(OpExpr *expr);
+static bool contain_dml(Node *node);
+static bool contain_dml_walker(Node *node, void *context);
+static bool contain_outer_selfref(Node *node);
+static bool contain_outer_selfref_walker(Node *node, Index *depth);
+static void inline_cte(PlannerInfo *root, CommonTableExpr *cte);
+static bool inline_cte_walker(Node *node, inline_cte_walker_context *context);
+static bool simplify_EXISTS_query(PlannerInfo *root, Query *query);
+static Query *convert_EXISTS_to_ANY(PlannerInfo *root, Query *subselect,
+									Node **testexpr, List **paramIds);
+static Node *replace_correlation_vars_mutator(Node *node, PlannerInfo *root);
+static Node *process_sublinks_mutator(Node *node,
+									  process_sublinks_context *context);
+static Bitmapset *finalize_plan(PlannerInfo *root,
+								Plan *plan,
+								int gather_param,
+								Bitmapset *valid_params,
+								Bitmapset *scan_params);
+static bool finalize_primnode(Node *node, finalize_primnode_context *context);
+static bool finalize_agg_primnode(Node *node, finalize_primnode_context *context);
+
+
+/*
+ * Get the datatype/typmod/collation of the first column of the plan's output.
+ *
+ * This information is stored for ARRAY_SUBLINK execution and for
+ * exprType()/exprTypmod()/exprCollation(), which have no way to get at the
+ * plan associated with a SubPlan node.  We really only need the info for
+ * EXPR_SUBLINK and ARRAY_SUBLINK subplans, but for consistency we save it
+ * always.
+ */
+static void
+get_first_col_type(Plan *plan, Oid *coltype, int32 *coltypmod,
+				   Oid *colcollation)
+{
+	/* In cases such as EXISTS, tlist might be empty; arbitrarily use VOID */
+	if (plan->targetlist)
+	{
+		TargetEntry *tent = linitial_node(TargetEntry, plan->targetlist);
+
+		if (!tent->resjunk)
+		{
+			*coltype = exprType((Node *) tent->expr);
+			*coltypmod = exprTypmod((Node *) tent->expr);
+			*colcollation = exprCollation((Node *) tent->expr);
+			return;
+		}
+	}
+	*coltype = VOIDOID;
+	*coltypmod = -1;
+	*colcollation = InvalidOid;
+}
+
+/*
+ * Convert a SubLink (as created by the parser) into a SubPlan.
+ *
+ * We are given the SubLink's contained query, type, ID, and testexpr.  We are
+ * also told if this expression appears at top level of a WHERE/HAVING qual.
+ *
+ * Note: we assume that the testexpr has been AND/OR flattened (actually,
+ * it's been through eval_const_expressions), but not converted to
+ * implicit-AND form; and any SubLinks in it should already have been
+ * converted to SubPlans.  The subquery is as yet untouched, however.
+ *
+ * The result is whatever we need to substitute in place of the SubLink node
+ * in the executable expression.  If we're going to do the subplan as a
+ * regular subplan, this will be the constructed SubPlan node.  If we're going
+ * to do the subplan as an InitPlan, the SubPlan node instead goes into
+ * root->init_plans, and what we return here is an expression tree
+ * representing the InitPlan's result: usually just a Param node representing
+ * a single scalar result, but possibly a row comparison tree containing
+ * multiple Param nodes, or for a MULTIEXPR subquery a simple NULL constant
+ * (since the real output Params are elsewhere in the tree, and the MULTIEXPR
+ * subquery itself is in a resjunk tlist entry whose value is uninteresting).
+ */
+static Node *
+make_subplan(PlannerInfo *root, Query *orig_subquery,
+			 SubLinkType subLinkType, int subLinkId,
+			 Node *testexpr, bool isTopQual)
+{
+	Query	   *subquery;
+	bool		simple_exists = false;
+	double		tuple_fraction;
+	PlannerInfo *subroot;
+	RelOptInfo *final_rel;
+	Path	   *best_path;
+	Plan	   *plan;
+	List	   *plan_params;
+	Node	   *result;
+
+	/*
+	 * Copy the source Query node.  This is a quick and dirty kluge to resolve
+	 * the fact that the parser can generate trees with multiple links to the
+	 * same sub-Query node, but the planner wants to scribble on the Query.
+	 * Try to clean this up when we do querytree redesign...
+	 */
+	subquery = copyObject(orig_subquery);
+
+	/*
+	 * If it's an EXISTS subplan, we might be able to simplify it.
+	 */
+	if (subLinkType == EXISTS_SUBLINK)
+		simple_exists = simplify_EXISTS_query(root, subquery);
+
+	/*
+	 * For an EXISTS subplan, tell lower-level planner to expect that only the
+	 * first tuple will be retrieved.  For ALL and ANY subplans, we will be
+	 * able to stop evaluating if the test condition fails or matches, so very
+	 * often not all the tuples will be retrieved; for lack of a better idea,
+	 * specify 50% retrieval.  For EXPR, MULTIEXPR, and ROWCOMPARE subplans,
+	 * use default behavior (we're only expecting one row out, anyway).
+	 *
+	 * NOTE: if you change these numbers, also change cost_subplan() in
+	 * path/costsize.c.
+	 *
+	 * XXX If an ANY subplan is uncorrelated, build_subplan may decide to hash
+	 * its output.  In that case it would've been better to specify full
+	 * retrieval.  At present, however, we can only check hashability after
+	 * we've made the subplan :-(.  (Determining whether it'll fit in hash_mem
+	 * is the really hard part.)  Therefore, we don't want to be too
+	 * optimistic about the percentage of tuples retrieved, for fear of
+	 * selecting a plan that's bad for the materialization case.
+	 */
+	if (subLinkType == EXISTS_SUBLINK)
+		tuple_fraction = 1.0;	/* just like a LIMIT 1 */
+	else if (subLinkType == ALL_SUBLINK ||
+			 subLinkType == ANY_SUBLINK)
+		tuple_fraction = 0.5;	/* 50% */
+	else
+		tuple_fraction = 0.0;	/* default behavior */
+
+	/* plan_params should not be in use in current query level */
+	Assert(root->plan_params == NIL);
+
+	/* Generate Paths for the subquery */
+	subroot = subquery_planner(root->glob, subquery,
+							   root,
+							   false, tuple_fraction);
+
+	/* Isolate the params needed by this specific subplan */
+	plan_params = root->plan_params;
+	root->plan_params = NIL;
+
+	/*
+	 * Select best Path and turn it into a Plan.  At least for now, there
+	 * seems no reason to postpone doing that.
+	 */
+	final_rel = fetch_upper_rel(subroot, UPPERREL_FINAL, NULL);
+	best_path = get_cheapest_fractional_path(final_rel, tuple_fraction);
+
+	plan = create_plan(subroot, best_path);
+
+	/* And convert to SubPlan or InitPlan format. */
+	result = build_subplan(root, plan, subroot, plan_params,
+						   subLinkType, subLinkId,
+						   testexpr, NIL, isTopQual);
+
+	/*
+	 * If it's a correlated EXISTS with an unimportant targetlist, we might be
+	 * able to transform it to the equivalent of an IN and then implement it
+	 * by hashing.  We don't have enough information yet to tell which way is
+	 * likely to be better (it depends on the expected number of executions of
+	 * the EXISTS qual, and we are much too early in planning the outer query
+	 * to be able to guess that).  So we generate both plans, if possible, and
+	 * leave it to setrefs.c to decide which to use.
+	 */
+	if (simple_exists && IsA(result, SubPlan))
+	{
+		Node	   *newtestexpr;
+		List	   *paramIds;
+
+		/* Make a second copy of the original subquery */
+		subquery = copyObject(orig_subquery);
+		/* and re-simplify */
+		simple_exists = simplify_EXISTS_query(root, subquery);
+		Assert(simple_exists);
+		/* See if it can be converted to an ANY query */
+		subquery = convert_EXISTS_to_ANY(root, subquery,
+										 &newtestexpr, &paramIds);
+		if (subquery)
+		{
+			/* Generate Paths for the ANY subquery; we'll need all rows */
+			subroot = subquery_planner(root->glob, subquery,
+									   root,
+									   false, 0.0);
+
+			/* Isolate the params needed by this specific subplan */
+			plan_params = root->plan_params;
+			root->plan_params = NIL;
+
+			/* Select best Path */
+			final_rel = fetch_upper_rel(subroot, UPPERREL_FINAL, NULL);
+			best_path = final_rel->cheapest_total_path;
+
+			/* Now we can check if it'll fit in hash_mem */
+			if (subpath_is_hashable(best_path))
+			{
+				SubPlan    *hashplan;
+				AlternativeSubPlan *asplan;
+
+				/* OK, finish planning the ANY subquery */
+				plan = create_plan(subroot, best_path);
+
+				/* ... and convert to SubPlan format */
+				hashplan = castNode(SubPlan,
+									build_subplan(root, plan, subroot,
+												  plan_params,
+												  ANY_SUBLINK, 0,
+												  newtestexpr,
+												  paramIds,
+												  true));
+				/* Check we got what we expected */
+				Assert(hashplan->parParam == NIL);
+				Assert(hashplan->useHashTable);
+
+				/* Leave it to setrefs.c to decide which plan to use */
+				asplan = makeNode(AlternativeSubPlan);
+				asplan->subplans = list_make2(result, hashplan);
+				result = (Node *) asplan;
+				root->hasAlternativeSubPlans = true;
+			}
+		}
+	}
+
+	return result;
+}
+
+/*
+ * Build a SubPlan node given the raw inputs --- subroutine for make_subplan
+ *
+ * Returns either the SubPlan, or a replacement expression if we decide to
+ * make it an InitPlan, as explained in the comments for make_subplan.
+ */
+static Node *
+build_subplan(PlannerInfo *root, Plan *plan, PlannerInfo *subroot,
+			  List *plan_params,
+			  SubLinkType subLinkType, int subLinkId,
+			  Node *testexpr, List *testexpr_paramids,
+			  bool unknownEqFalse)
+{
+	Node	   *result;
+	SubPlan    *splan;
+	bool		isInitPlan;
+	ListCell   *lc;
+
+	/*
+	 * Initialize the SubPlan node.  Note plan_id, plan_name, and cost fields
+	 * are set further down.
+	 */
+	splan = makeNode(SubPlan);
+	splan->subLinkType = subLinkType;
+	splan->testexpr = NULL;
+	splan->paramIds = NIL;
+	get_first_col_type(plan, &splan->firstColType, &splan->firstColTypmod,
+					   &splan->firstColCollation);
+	splan->useHashTable = false;
+	splan->unknownEqFalse = unknownEqFalse;
+	splan->parallel_safe = plan->parallel_safe;
+	splan->setParam = NIL;
+	splan->parParam = NIL;
+	splan->args = NIL;
+
+	/*
+	 * Make parParam and args lists of param IDs and expressions that current
+	 * query level will pass to this child plan.
+	 */
+	foreach(lc, plan_params)
+	{
+		PlannerParamItem *pitem = (PlannerParamItem *) lfirst(lc);
+		Node	   *arg = pitem->item;
+
+		/*
+		 * The Var, PlaceHolderVar, Aggref or GroupingFunc has already been
+		 * adjusted to have the correct varlevelsup, phlevelsup, or
+		 * agglevelsup.
+		 *
+		 * If it's a PlaceHolderVar, Aggref or GroupingFunc, its arguments
+		 * might contain SubLinks, which have not yet been processed (see the
+		 * comments for SS_replace_correlation_vars).  Do that now.
+		 */
+		if (IsA(arg, PlaceHolderVar) ||
+			IsA(arg, Aggref) ||
+			IsA(arg, GroupingFunc))
+			arg = SS_process_sublinks(root, arg, false);
+
+		splan->parParam = lappend_int(splan->parParam, pitem->paramId);
+		splan->args = lappend(splan->args, arg);
+	}
+
+	/*
+	 * Un-correlated or undirect correlated plans of EXISTS, EXPR, ARRAY,
+	 * ROWCOMPARE, or MULTIEXPR types can be used as initPlans.  For EXISTS,
+	 * EXPR, or ARRAY, we return a Param referring to the result of evaluating
+	 * the initPlan.  For ROWCOMPARE, we must modify the testexpr tree to
+	 * contain PARAM_EXEC Params instead of the PARAM_SUBLINK Params emitted
+	 * by the parser, and then return that tree.  For MULTIEXPR, we return a
+	 * null constant: the resjunk targetlist item containing the SubLink does
+	 * not need to return anything useful, since the referencing Params are
+	 * elsewhere.
+	 */
+	if (splan->parParam == NIL && subLinkType == EXISTS_SUBLINK)
+	{
+		Param	   *prm;
+
+		Assert(testexpr == NULL);
+		prm = generate_new_exec_param(root, BOOLOID, -1, InvalidOid);
+		splan->setParam = list_make1_int(prm->paramid);
+		isInitPlan = true;
+		result = (Node *) prm;
+	}
+	else if (splan->parParam == NIL && subLinkType == EXPR_SUBLINK)
+	{
+		TargetEntry *te = linitial(plan->targetlist);
+		Param	   *prm;
+
+		Assert(!te->resjunk);
+		Assert(testexpr == NULL);
+		prm = generate_new_exec_param(root,
+									  exprType((Node *) te->expr),
+									  exprTypmod((Node *) te->expr),
+									  exprCollation((Node *) te->expr));
+		splan->setParam = list_make1_int(prm->paramid);
+		isInitPlan = true;
+		result = (Node *) prm;
+	}
+	else if (splan->parParam == NIL && subLinkType == ARRAY_SUBLINK)
+	{
+		TargetEntry *te = linitial(plan->targetlist);
+		Oid			arraytype;
+		Param	   *prm;
+
+		Assert(!te->resjunk);
+		Assert(testexpr == NULL);
+		arraytype = get_promoted_array_type(exprType((Node *) te->expr));
+		if (!OidIsValid(arraytype))
+			elog(ERROR, "could not find array type for datatype %s",
+				 format_type_be(exprType((Node *) te->expr)));
+		prm = generate_new_exec_param(root,
+									  arraytype,
+									  exprTypmod((Node *) te->expr),
+									  exprCollation((Node *) te->expr));
+		splan->setParam = list_make1_int(prm->paramid);
+		isInitPlan = true;
+		result = (Node *) prm;
+	}
+	else if (splan->parParam == NIL && subLinkType == ROWCOMPARE_SUBLINK)
+	{
+		/* Adjust the Params */
+		List	   *params;
+
+		Assert(testexpr != NULL);
+		params = generate_subquery_params(root,
+										  plan->targetlist,
+										  &splan->paramIds);
+		result = convert_testexpr(root,
+								  testexpr,
+								  params);
+		splan->setParam = list_copy(splan->paramIds);
+		isInitPlan = true;
+
+		/*
+		 * The executable expression is returned to become part of the outer
+		 * plan's expression tree; it is not kept in the initplan node.
+		 */
+	}
+	else if (subLinkType == MULTIEXPR_SUBLINK)
+	{
+		/*
+		 * Whether it's an initplan or not, it needs to set a PARAM_EXEC Param
+		 * for each output column.
+		 */
+		List	   *params;
+
+		Assert(testexpr == NULL);
+		params = generate_subquery_params(root,
+										  plan->targetlist,
+										  &splan->setParam);
+
+		/*
+		 * Save the list of replacement Params in the n'th cell of
+		 * root->multiexpr_params; setrefs.c will use it to replace
+		 * PARAM_MULTIEXPR Params.
+		 */
+		while (list_length(root->multiexpr_params) < subLinkId)
+			root->multiexpr_params = lappend(root->multiexpr_params, NIL);
+		lc = list_nth_cell(root->multiexpr_params, subLinkId - 1);
+		Assert(lfirst(lc) == NIL);
+		lfirst(lc) = params;
+
+		/* It can be an initplan if there are no parParams. */
+		if (splan->parParam == NIL)
+		{
+			isInitPlan = true;
+			result = (Node *) makeNullConst(RECORDOID, -1, InvalidOid);
+		}
+		else
+		{
+			isInitPlan = false;
+			result = (Node *) splan;
+		}
+	}
+	else
+	{
+		/*
+		 * Adjust the Params in the testexpr, unless caller already took care
+		 * of it (as indicated by passing a list of Param IDs).
+		 */
+		if (testexpr && testexpr_paramids == NIL)
+		{
+			List	   *params;
+
+			params = generate_subquery_params(root,
+											  plan->targetlist,
+											  &splan->paramIds);
+			splan->testexpr = convert_testexpr(root,
+											   testexpr,
+											   params);
+		}
+		else
+		{
+			splan->testexpr = testexpr;
+			splan->paramIds = testexpr_paramids;
+		}
+
+		/*
+		 * We can't convert subplans of ALL_SUBLINK or ANY_SUBLINK types to
+		 * initPlans, even when they are uncorrelated or undirect correlated,
+		 * because we need to scan the output of the subplan for each outer
+		 * tuple.  But if it's a not-direct-correlated IN (= ANY) test, we
+		 * might be able to use a hashtable to avoid comparing all the tuples.
+		 */
+		if (subLinkType == ANY_SUBLINK &&
+			splan->parParam == NIL &&
+			subplan_is_hashable(plan) &&
+			testexpr_is_hashable(splan->testexpr, splan->paramIds))
+			splan->useHashTable = true;
+
+		/*
+		 * Otherwise, we have the option to tack a Material node onto the top
+		 * of the subplan, to reduce the cost of reading it repeatedly.  This
+		 * is pointless for a direct-correlated subplan, since we'd have to
+		 * recompute its results each time anyway.  For uncorrelated/undirect
+		 * correlated subplans, we add Material unless the subplan's top plan
+		 * node would materialize its output anyway.  Also, if enable_material
+		 * is false, then the user does not want us to materialize anything
+		 * unnecessarily, so we don't.
+		 */
+		else if (splan->parParam == NIL && enable_material &&
+				 !ExecMaterializesOutput(nodeTag(plan)))
+			plan = materialize_finished_plan(plan);
+
+		result = (Node *) splan;
+		isInitPlan = false;
+	}
+
+	/*
+	 * Add the subplan and its PlannerInfo to the global lists.
+	 */
+	root->glob->subplans = lappend(root->glob->subplans, plan);
+	root->glob->subroots = lappend(root->glob->subroots, subroot);
+	splan->plan_id = list_length(root->glob->subplans);
+
+	if (isInitPlan)
+		root->init_plans = lappend(root->init_plans, splan);
+
+	/*
+	 * A parameterless subplan (not initplan) should be prepared to handle
+	 * REWIND efficiently.  If it has direct parameters then there's no point
+	 * since it'll be reset on each scan anyway; and if it's an initplan then
+	 * there's no point since it won't get re-run without parameter changes
+	 * anyway.  The input of a hashed subplan doesn't need REWIND either.
+	 */
+	if (splan->parParam == NIL && !isInitPlan && !splan->useHashTable)
+		root->glob->rewindPlanIDs = bms_add_member(root->glob->rewindPlanIDs,
+												   splan->plan_id);
+
+	/* Label the subplan for EXPLAIN purposes */
+	splan->plan_name = palloc(32 + 12 * list_length(splan->setParam));
+	sprintf(splan->plan_name, "%s %d",
+			isInitPlan ? "InitPlan" : "SubPlan",
+			splan->plan_id);
+	if (splan->setParam)
+	{
+		char	   *ptr = splan->plan_name + strlen(splan->plan_name);
+
+		ptr += sprintf(ptr, " (returns ");
+		foreach(lc, splan->setParam)
+		{
+			ptr += sprintf(ptr, "$%d%s",
+						   lfirst_int(lc),
+						   lnext(splan->setParam, lc) ? "," : ")");
+		}
+	}
+
+	/* Lastly, fill in the cost estimates for use later */
+	cost_subplan(root, splan, plan);
+
+	return result;
+}
+
+/*
+ * generate_subquery_params: build a list of Params representing the output
+ * columns of a sublink's sub-select, given the sub-select's targetlist.
+ *
+ * We also return an integer list of the paramids of the Params.
+ */
+static List *
+generate_subquery_params(PlannerInfo *root, List *tlist, List **paramIds)
+{
+	List	   *result;
+	List	   *ids;
+	ListCell   *lc;
+
+	result = ids = NIL;
+	foreach(lc, tlist)
+	{
+		TargetEntry *tent = (TargetEntry *) lfirst(lc);
+		Param	   *param;
+
+		if (tent->resjunk)
+			continue;
+
+		param = generate_new_exec_param(root,
+										exprType((Node *) tent->expr),
+										exprTypmod((Node *) tent->expr),
+										exprCollation((Node *) tent->expr));
+		result = lappend(result, param);
+		ids = lappend_int(ids, param->paramid);
+	}
+
+	*paramIds = ids;
+	return result;
+}
+
+/*
+ * generate_subquery_vars: build a list of Vars representing the output
+ * columns of a sublink's sub-select, given the sub-select's targetlist.
+ * The Vars have the specified varno (RTE index).
+ */
+static List *
+generate_subquery_vars(PlannerInfo *root, List *tlist, Index varno)
+{
+	List	   *result;
+	ListCell   *lc;
+
+	result = NIL;
+	foreach(lc, tlist)
+	{
+		TargetEntry *tent = (TargetEntry *) lfirst(lc);
+		Var		   *var;
+
+		if (tent->resjunk)
+			continue;
+
+		var = makeVarFromTargetEntry(varno, tent);
+		result = lappend(result, var);
+	}
+
+	return result;
+}
+
+/*
+ * convert_testexpr: convert the testexpr given by the parser into
+ * actually executable form.  This entails replacing PARAM_SUBLINK Params
+ * with Params or Vars representing the results of the sub-select.  The
+ * nodes to be substituted are passed in as the List result from
+ * generate_subquery_params or generate_subquery_vars.
+ */
+static Node *
+convert_testexpr(PlannerInfo *root,
+				 Node *testexpr,
+				 List *subst_nodes)
+{
+	convert_testexpr_context context;
+
+	context.root = root;
+	context.subst_nodes = subst_nodes;
+	return convert_testexpr_mutator(testexpr, &context);
+}
+
+static Node *
+convert_testexpr_mutator(Node *node,
+						 convert_testexpr_context *context)
+{
+	if (node == NULL)
+		return NULL;
+	if (IsA(node, Param))
+	{
+		Param	   *param = (Param *) node;
+
+		if (param->paramkind == PARAM_SUBLINK)
+		{
+			if (param->paramid <= 0 ||
+				param->paramid > list_length(context->subst_nodes))
+				elog(ERROR, "unexpected PARAM_SUBLINK ID: %d", param->paramid);
+
+			/*
+			 * We copy the list item to avoid having doubly-linked
+			 * substructure in the modified parse tree.  This is probably
+			 * unnecessary when it's a Param, but be safe.
+			 */
+			return (Node *) copyObject(list_nth(context->subst_nodes,
+												param->paramid - 1));
+		}
+	}
+	if (IsA(node, SubLink))
+	{
+		/*
+		 * If we come across a nested SubLink, it is neither necessary nor
+		 * correct to recurse into it: any PARAM_SUBLINKs we might find inside
+		 * belong to the inner SubLink not the outer. So just return it as-is.
+		 *
+		 * This reasoning depends on the assumption that nothing will pull
+		 * subexpressions into or out of the testexpr field of a SubLink, at
+		 * least not without replacing PARAM_SUBLINKs first.  If we did want
+		 * to do that we'd need to rethink the parser-output representation
+		 * altogether, since currently PARAM_SUBLINKs are only unique per
+		 * SubLink not globally across the query.  The whole point of
+		 * replacing them with Vars or PARAM_EXEC nodes is to make them
+		 * globally unique before they escape from the SubLink's testexpr.
+		 *
+		 * Note: this can't happen when called during SS_process_sublinks,
+		 * because that recursively processes inner SubLinks first.  It can
+		 * happen when called from convert_ANY_sublink_to_join, though.
+		 */
+		return node;
+	}
+	return expression_tree_mutator(node,
+								   convert_testexpr_mutator,
+								   (void *) context);
+}
+
+/*
+ * subplan_is_hashable: can we implement an ANY subplan by hashing?
+ *
+ * This is not responsible for checking whether the combining testexpr
+ * is suitable for hashing.  We only look at the subquery itself.
+ */
+static bool
+subplan_is_hashable(Plan *plan)
+{
+	double		subquery_size;
+
+	/*
+	 * The estimated size of the subquery result must fit in hash_mem. (Note:
+	 * we use heap tuple overhead here even though the tuples will actually be
+	 * stored as MinimalTuples; this provides some fudge factor for hashtable
+	 * overhead.)
+	 */
+	subquery_size = plan->plan_rows *
+		(MAXALIGN(plan->plan_width) + MAXALIGN(SizeofHeapTupleHeader));
+	if (subquery_size > get_hash_memory_limit())
+		return false;
+
+	return true;
+}
+
+/*
+ * subpath_is_hashable: can we implement an ANY subplan by hashing?
+ *
+ * Identical to subplan_is_hashable, but work from a Path for the subplan.
+ */
+static bool
+subpath_is_hashable(Path *path)
+{
+	double		subquery_size;
+
+	/*
+	 * The estimated size of the subquery result must fit in hash_mem. (Note:
+	 * we use heap tuple overhead here even though the tuples will actually be
+	 * stored as MinimalTuples; this provides some fudge factor for hashtable
+	 * overhead.)
+	 */
+	subquery_size = path->rows *
+		(MAXALIGN(path->pathtarget->width) + MAXALIGN(SizeofHeapTupleHeader));
+	if (subquery_size > get_hash_memory_limit())
+		return false;
+
+	return true;
+}
+
+/*
+ * testexpr_is_hashable: is an ANY SubLink's test expression hashable?
+ *
+ * To identify LHS vs RHS of the hash expression, we must be given the
+ * list of output Param IDs of the SubLink's subquery.
+ */
+static bool
+testexpr_is_hashable(Node *testexpr, List *param_ids)
+{
+	/*
+	 * The testexpr must be a single OpExpr, or an AND-clause containing only
+	 * OpExprs, each of which satisfy test_opexpr_is_hashable().
+	 */
+	if (testexpr && IsA(testexpr, OpExpr))
+	{
+		if (test_opexpr_is_hashable((OpExpr *) testexpr, param_ids))
+			return true;
+	}
+	else if (is_andclause(testexpr))
+	{
+		ListCell   *l;
+
+		foreach(l, ((BoolExpr *) testexpr)->args)
+		{
+			Node	   *andarg = (Node *) lfirst(l);
+
+			if (!IsA(andarg, OpExpr))
+				return false;
+			if (!test_opexpr_is_hashable((OpExpr *) andarg, param_ids))
+				return false;
+		}
+		return true;
+	}
+
+	return false;
+}
+
+static bool
+test_opexpr_is_hashable(OpExpr *testexpr, List *param_ids)
+{
+	/*
+	 * The combining operator must be hashable and strict.  The need for
+	 * hashability is obvious, since we want to use hashing.  Without
+	 * strictness, behavior in the presence of nulls is too unpredictable.  We
+	 * actually must assume even more than plain strictness: it can't yield
+	 * NULL for non-null inputs, either (see nodeSubplan.c).  However, hash
+	 * indexes and hash joins assume that too.
+	 */
+	if (!hash_ok_operator(testexpr))
+		return false;
+
+	/*
+	 * The left and right inputs must belong to the outer and inner queries
+	 * respectively; hence Params that will be supplied by the subquery must
+	 * not appear in the LHS, and Vars of the outer query must not appear in
+	 * the RHS.  (Ordinarily, this must be true because of the way that the
+	 * parser builds an ANY SubLink's testexpr ... but inlining of functions
+	 * could have changed the expression's structure, so we have to check.
+	 * Such cases do not occur often enough to be worth trying to optimize, so
+	 * we don't worry about trying to commute the clause or anything like
+	 * that; we just need to be sure not to build an invalid plan.)
+	 */
+	if (list_length(testexpr->args) != 2)
+		return false;
+	if (contain_exec_param((Node *) linitial(testexpr->args), param_ids))
+		return false;
+	if (contain_var_clause((Node *) lsecond(testexpr->args)))
+		return false;
+	return true;
+}
+
+/*
+ * Check expression is hashable + strict
+ *
+ * We could use op_hashjoinable() and op_strict(), but do it like this to
+ * avoid a redundant cache lookup.
+ */
+static bool
+hash_ok_operator(OpExpr *expr)
+{
+	Oid			opid = expr->opno;
+
+	/* quick out if not a binary operator */
+	if (list_length(expr->args) != 2)
+		return false;
+	if (opid == ARRAY_EQ_OP ||
+		opid == RECORD_EQ_OP)
+	{
+		/* these are strict, but must check input type to ensure hashable */
+		Node	   *leftarg = linitial(expr->args);
+
+		return op_hashjoinable(opid, exprType(leftarg));
+	}
+	else
+	{
+		/* else must look up the operator properties */
+		HeapTuple	tup;
+		Form_pg_operator optup;
+
+		tup = SearchSysCache1(OPEROID, ObjectIdGetDatum(opid));
+		if (!HeapTupleIsValid(tup))
+			elog(ERROR, "cache lookup failed for operator %u", opid);
+		optup = (Form_pg_operator) GETSTRUCT(tup);
+		if (!optup->oprcanhash || !func_strict(optup->oprcode))
+		{
+			ReleaseSysCache(tup);
+			return false;
+		}
+		ReleaseSysCache(tup);
+		return true;
+	}
+}
+
+
+/*
+ * SS_process_ctes: process a query's WITH list
+ *
+ * Consider each CTE in the WITH list and either ignore it (if it's an
+ * unreferenced SELECT), "inline" it to create a regular sub-SELECT-in-FROM,
+ * or convert it to an initplan.
+ *
+ * A side effect is to fill in root->cte_plan_ids with a list that
+ * parallels root->parse->cteList and provides the subplan ID for
+ * each CTE's initplan, or a dummy ID (-1) if we didn't make an initplan.
+ */
+void
+SS_process_ctes(PlannerInfo *root)
+{
+	ListCell   *lc;
+
+	Assert(root->cte_plan_ids == NIL);
+
+	foreach(lc, root->parse->cteList)
+	{
+		CommonTableExpr *cte = (CommonTableExpr *) lfirst(lc);
+		CmdType		cmdType = ((Query *) cte->ctequery)->commandType;
+		Query	   *subquery;
+		PlannerInfo *subroot;
+		RelOptInfo *final_rel;
+		Path	   *best_path;
+		Plan	   *plan;
+		SubPlan    *splan;
+		int			paramid;
+
+		/*
+		 * Ignore SELECT CTEs that are not actually referenced anywhere.
+		 */
+		if (cte->cterefcount == 0 && cmdType == CMD_SELECT)
+		{
+			/* Make a dummy entry in cte_plan_ids */
+			root->cte_plan_ids = lappend_int(root->cte_plan_ids, -1);
+			continue;
+		}
+
+		/*
+		 * Consider inlining the CTE (creating RTE_SUBQUERY RTE(s)) instead of
+		 * implementing it as a separately-planned CTE.
+		 *
+		 * We cannot inline if any of these conditions hold:
+		 *
+		 * 1. The user said not to (the CTEMaterializeAlways option).
+		 *
+		 * 2. The CTE is recursive.
+		 *
+		 * 3. The CTE has side-effects; this includes either not being a plain
+		 * SELECT, or containing volatile functions.  Inlining might change
+		 * the side-effects, which would be bad.
+		 *
+		 * 4. The CTE is multiply-referenced and contains a self-reference to
+		 * a recursive CTE outside itself.  Inlining would result in multiple
+		 * recursive self-references, which we don't support.
+		 *
+		 * Otherwise, we have an option whether to inline or not.  That should
+		 * always be a win if there's just a single reference, but if the CTE
+		 * is multiply-referenced then it's unclear: inlining adds duplicate
+		 * computations, but the ability to absorb restrictions from the outer
+		 * query level could outweigh that.  We do not have nearly enough
+		 * information at this point to tell whether that's true, so we let
+		 * the user express a preference.  Our default behavior is to inline
+		 * only singly-referenced CTEs, but a CTE marked CTEMaterializeNever
+		 * will be inlined even if multiply referenced.
+		 *
+		 * Note: we check for volatile functions last, because that's more
+		 * expensive than the other tests needed.
+		 */
+		if ((cte->ctematerialized == CTEMaterializeNever ||
+			 (cte->ctematerialized == CTEMaterializeDefault &&
+			  cte->cterefcount == 1)) &&
+			!cte->cterecursive &&
+			cmdType == CMD_SELECT &&
+			!contain_dml(cte->ctequery) &&
+			(cte->cterefcount <= 1 ||
+			 !contain_outer_selfref(cte->ctequery)) &&
+			!contain_volatile_functions(cte->ctequery))
+		{
+			inline_cte(root, cte);
+			/* Make a dummy entry in cte_plan_ids */
+			root->cte_plan_ids = lappend_int(root->cte_plan_ids, -1);
+			continue;
+		}
+
+		/*
+		 * Copy the source Query node.  Probably not necessary, but let's keep
+		 * this similar to make_subplan.
+		 */
+		subquery = (Query *) copyObject(cte->ctequery);
+
+		/* plan_params should not be in use in current query level */
+		Assert(root->plan_params == NIL);
+
+		/*
+		 * Generate Paths for the CTE query.  Always plan for full retrieval
+		 * --- we don't have enough info to predict otherwise.
+		 */
+		subroot = subquery_planner(root->glob, subquery,
+								   root,
+								   cte->cterecursive, 0.0);
+
+		/*
+		 * Since the current query level doesn't yet contain any RTEs, it
+		 * should not be possible for the CTE to have requested parameters of
+		 * this level.
+		 */
+		if (root->plan_params)
+			elog(ERROR, "unexpected outer reference in CTE query");
+
+		/*
+		 * Select best Path and turn it into a Plan.  At least for now, there
+		 * seems no reason to postpone doing that.
+		 */
+		final_rel = fetch_upper_rel(subroot, UPPERREL_FINAL, NULL);
+		best_path = final_rel->cheapest_total_path;
+
+		plan = create_plan(subroot, best_path);
+
+		/*
+		 * Make a SubPlan node for it.  This is just enough unlike
+		 * build_subplan that we can't share code.
+		 *
+		 * Note plan_id, plan_name, and cost fields are set further down.
+		 */
+		splan = makeNode(SubPlan);
+		splan->subLinkType = CTE_SUBLINK;
+		splan->testexpr = NULL;
+		splan->paramIds = NIL;
+		get_first_col_type(plan, &splan->firstColType, &splan->firstColTypmod,
+						   &splan->firstColCollation);
+		splan->useHashTable = false;
+		splan->unknownEqFalse = false;
+
+		/*
+		 * CTE scans are not considered for parallelism (cf
+		 * set_rel_consider_parallel), and even if they were, initPlans aren't
+		 * parallel-safe.
+		 */
+		splan->parallel_safe = false;
+		splan->setParam = NIL;
+		splan->parParam = NIL;
+		splan->args = NIL;
+
+		/*
+		 * The node can't have any inputs (since it's an initplan), so the
+		 * parParam and args lists remain empty.  (It could contain references
+		 * to earlier CTEs' output param IDs, but CTE outputs are not
+		 * propagated via the args list.)
+		 */
+
+		/*
+		 * Assign a param ID to represent the CTE's output.  No ordinary
+		 * "evaluation" of this param slot ever happens, but we use the param
+		 * ID for setParam/chgParam signaling just as if the CTE plan were
+		 * returning a simple scalar output.  (Also, the executor abuses the
+		 * ParamExecData slot for this param ID for communication among
+		 * multiple CteScan nodes that might be scanning this CTE.)
+		 */
+		paramid = assign_special_exec_param(root);
+		splan->setParam = list_make1_int(paramid);
+
+		/*
+		 * Add the subplan and its PlannerInfo to the global lists.
+		 */
+		root->glob->subplans = lappend(root->glob->subplans, plan);
+		root->glob->subroots = lappend(root->glob->subroots, subroot);
+		splan->plan_id = list_length(root->glob->subplans);
+
+		root->init_plans = lappend(root->init_plans, splan);
+
+		root->cte_plan_ids = lappend_int(root->cte_plan_ids, splan->plan_id);
+
+		/* Label the subplan for EXPLAIN purposes */
+		splan->plan_name = psprintf("CTE %s", cte->ctename);
+
+		/* Lastly, fill in the cost estimates for use later */
+		cost_subplan(root, splan, plan);
+	}
+}
+
+/*
+ * contain_dml: is any subquery not a plain SELECT?
+ *
+ * We reject SELECT FOR UPDATE/SHARE as well as INSERT etc.
+ */
+static bool
+contain_dml(Node *node)
+{
+	return contain_dml_walker(node, NULL);
+}
+
+static bool
+contain_dml_walker(Node *node, void *context)
+{
+	if (node == NULL)
+		return false;
+	if (IsA(node, Query))
+	{
+		Query	   *query = (Query *) node;
+
+		if (query->commandType != CMD_SELECT ||
+			query->rowMarks != NIL)
+			return true;
+
+		return query_tree_walker(query, contain_dml_walker, context, 0);
+	}
+	return expression_tree_walker(node, contain_dml_walker, context);
+}
+
+/*
+ * contain_outer_selfref: is there an external recursive self-reference?
+ */
+static bool
+contain_outer_selfref(Node *node)
+{
+	Index		depth = 0;
+
+	/*
+	 * We should be starting with a Query, so that depth will be 1 while
+	 * examining its immediate contents.
+	 */
+	Assert(IsA(node, Query));
+
+	return contain_outer_selfref_walker(node, &depth);
+}
+
+static bool
+contain_outer_selfref_walker(Node *node, Index *depth)
+{
+	if (node == NULL)
+		return false;
+	if (IsA(node, RangeTblEntry))
+	{
+		RangeTblEntry *rte = (RangeTblEntry *) node;
+
+		/*
+		 * Check for a self-reference to a CTE that's above the Query that our
+		 * search started at.
+		 */
+		if (rte->rtekind == RTE_CTE &&
+			rte->self_reference &&
+			rte->ctelevelsup >= *depth)
+			return true;
+		return false;			/* allow range_table_walker to continue */
+	}
+	if (IsA(node, Query))
+	{
+		/* Recurse into subquery, tracking nesting depth properly */
+		Query	   *query = (Query *) node;
+		bool		result;
+
+		(*depth)++;
+
+		result = query_tree_walker(query, contain_outer_selfref_walker,
+								   (void *) depth, QTW_EXAMINE_RTES_BEFORE);
+
+		(*depth)--;
+
+		return result;
+	}
+	return expression_tree_walker(node, contain_outer_selfref_walker,
+								  (void *) depth);
+}
+
+/*
+ * inline_cte: convert RTE_CTE references to given CTE into RTE_SUBQUERYs
+ */
+static void
+inline_cte(PlannerInfo *root, CommonTableExpr *cte)
+{
+	struct inline_cte_walker_context context;
+
+	context.ctename = cte->ctename;
+	/* Start at levelsup = -1 because we'll immediately increment it */
+	context.levelsup = -1;
+	context.ctequery = castNode(Query, cte->ctequery);
+
+	(void) inline_cte_walker((Node *) root->parse, &context);
+}
+
+static bool
+inline_cte_walker(Node *node, inline_cte_walker_context *context)
+{
+	if (node == NULL)
+		return false;
+	if (IsA(node, Query))
+	{
+		Query	   *query = (Query *) node;
+
+		context->levelsup++;
+
+		/*
+		 * Visit the query's RTE nodes after their contents; otherwise
+		 * query_tree_walker would descend into the newly inlined CTE query,
+		 * which we don't want.
+		 */
+		(void) query_tree_walker(query, inline_cte_walker, context,
+								 QTW_EXAMINE_RTES_AFTER);
+
+		context->levelsup--;
+
+		return false;
+	}
+	else if (IsA(node, RangeTblEntry))
+	{
+		RangeTblEntry *rte = (RangeTblEntry *) node;
+
+		if (rte->rtekind == RTE_CTE &&
+			strcmp(rte->ctename, context->ctename) == 0 &&
+			rte->ctelevelsup == context->levelsup)
+		{
+			/*
+			 * Found a reference to replace.  Generate a copy of the CTE query
+			 * with appropriate level adjustment for outer references (e.g.,
+			 * to other CTEs).
+			 */
+			Query	   *newquery = copyObject(context->ctequery);
+
+			if (context->levelsup > 0)
+				IncrementVarSublevelsUp((Node *) newquery, context->levelsup, 1);
+
+			/*
+			 * Convert the RTE_CTE RTE into a RTE_SUBQUERY.
+			 *
+			 * Historically, a FOR UPDATE clause has been treated as extending
+			 * into views and subqueries, but not into CTEs.  We preserve this
+			 * distinction by not trying to push rowmarks into the new
+			 * subquery.
+			 */
+			rte->rtekind = RTE_SUBQUERY;
+			rte->subquery = newquery;
+			rte->security_barrier = false;
+
+			/* Zero out CTE-specific fields */
+			rte->ctename = NULL;
+			rte->ctelevelsup = 0;
+			rte->self_reference = false;
+			rte->coltypes = NIL;
+			rte->coltypmods = NIL;
+			rte->colcollations = NIL;
+		}
+
+		return false;
+	}
+
+	return expression_tree_walker(node, inline_cte_walker, context);
+}
+
+
+/*
+ * convert_ANY_sublink_to_join: try to convert an ANY SubLink to a join
+ *
+ * The caller has found an ANY SubLink at the top level of one of the query's
+ * qual clauses, but has not checked the properties of the SubLink further.
+ * Decide whether it is appropriate to process this SubLink in join style.
+ * If so, form a JoinExpr and return it.  Return NULL if the SubLink cannot
+ * be converted to a join.
+ *
+ * The only non-obvious input parameter is available_rels: this is the set
+ * of query rels that can safely be referenced in the sublink expression.
+ * (We must restrict this to avoid changing the semantics when a sublink
+ * is present in an outer join's ON qual.)  The conversion must fail if
+ * the converted qual would reference any but these parent-query relids.
+ *
+ * On success, the returned JoinExpr has larg = NULL and rarg = the jointree
+ * item representing the pulled-up subquery.  The caller must set larg to
+ * represent the relation(s) on the lefthand side of the new join, and insert
+ * the JoinExpr into the upper query's jointree at an appropriate place
+ * (typically, where the lefthand relation(s) had been).  Note that the
+ * passed-in SubLink must also be removed from its original position in the
+ * query quals, since the quals of the returned JoinExpr replace it.
+ * (Notionally, we replace the SubLink with a constant TRUE, then elide the
+ * redundant constant from the qual.)
+ *
+ * On success, the caller is also responsible for recursively applying
+ * pull_up_sublinks processing to the rarg and quals of the returned JoinExpr.
+ * (On failure, there is no need to do anything, since pull_up_sublinks will
+ * be applied when we recursively plan the sub-select.)
+ *
+ * Side effects of a successful conversion include adding the SubLink's
+ * subselect to the query's rangetable, so that it can be referenced in
+ * the JoinExpr's rarg.
+ */
+JoinExpr *
+convert_ANY_sublink_to_join(PlannerInfo *root, SubLink *sublink,
+							Relids available_rels)
+{
+	JoinExpr   *result;
+	Query	   *parse = root->parse;
+	Query	   *subselect = (Query *) sublink->subselect;
+	Relids		upper_varnos;
+	int			rtindex;
+	ParseNamespaceItem *nsitem;
+	RangeTblEntry *rte;
+	RangeTblRef *rtr;
+	List	   *subquery_vars;
+	Node	   *quals;
+	ParseState *pstate;
+
+	Assert(sublink->subLinkType == ANY_SUBLINK);
+
+	/*
+	 * The sub-select must not refer to any Vars of the parent query. (Vars of
+	 * higher levels should be okay, though.)
+	 */
+	if (contain_vars_of_level((Node *) subselect, 1))
+		return NULL;
+
+	/*
+	 * The test expression must contain some Vars of the parent query, else
+	 * it's not gonna be a join.  (Note that it won't have Vars referring to
+	 * the subquery, rather Params.)
+	 */
+	upper_varnos = pull_varnos(root, sublink->testexpr);
+	if (bms_is_empty(upper_varnos))
+		return NULL;
+
+	/*
+	 * However, it can't refer to anything outside available_rels.
+	 */
+	if (!bms_is_subset(upper_varnos, available_rels))
+		return NULL;
+
+	/*
+	 * The combining operators and left-hand expressions mustn't be volatile.
+	 */
+	if (contain_volatile_functions(sublink->testexpr))
+		return NULL;
+
+	/* Create a dummy ParseState for addRangeTableEntryForSubquery */
+	pstate = make_parsestate(NULL);
+
+	/*
+	 * Okay, pull up the sub-select into upper range table.
+	 *
+	 * We rely here on the assumption that the outer query has no references
+	 * to the inner (necessarily true, other than the Vars that we build
+	 * below). Therefore this is a lot easier than what pull_up_subqueries has
+	 * to go through.
+	 */
+	nsitem = addRangeTableEntryForSubquery(pstate,
+										   subselect,
+										   makeAlias("ANY_subquery", NIL),
+										   false,
+										   false);
+	rte = nsitem->p_rte;
+	parse->rtable = lappend(parse->rtable, rte);
+	rtindex = list_length(parse->rtable);
+
+	/*
+	 * Form a RangeTblRef for the pulled-up sub-select.
+	 */
+	rtr = makeNode(RangeTblRef);
+	rtr->rtindex = rtindex;
+
+	/*
+	 * Build a list of Vars representing the subselect outputs.
+	 */
+	subquery_vars = generate_subquery_vars(root,
+										   subselect->targetList,
+										   rtindex);
+
+	/*
+	 * Build the new join's qual expression, replacing Params with these Vars.
+	 */
+	quals = convert_testexpr(root, sublink->testexpr, subquery_vars);
+
+	/*
+	 * And finally, build the JoinExpr node.
+	 */
+	result = makeNode(JoinExpr);
+	result->jointype = JOIN_SEMI;
+	result->isNatural = false;
+	result->larg = NULL;		/* caller must fill this in */
+	result->rarg = (Node *) rtr;
+	result->usingClause = NIL;
+	result->join_using_alias = NULL;
+	result->quals = quals;
+	result->alias = NULL;
+	result->rtindex = 0;		/* we don't need an RTE for it */
+
+	return result;
+}
+
+/*
+ * convert_EXISTS_sublink_to_join: try to convert an EXISTS SubLink to a join
+ *
+ * The API of this function is identical to convert_ANY_sublink_to_join's,
+ * except that we also support the case where the caller has found NOT EXISTS,
+ * so we need an additional input parameter "under_not".
+ */
+JoinExpr *
+convert_EXISTS_sublink_to_join(PlannerInfo *root, SubLink *sublink,
+							   bool under_not, Relids available_rels)
+{
+	JoinExpr   *result;
+	Query	   *parse = root->parse;
+	Query	   *subselect = (Query *) sublink->subselect;
+	Node	   *whereClause;
+	int			rtoffset;
+	int			varno;
+	Relids		clause_varnos;
+	Relids		upper_varnos;
+
+	Assert(sublink->subLinkType == EXISTS_SUBLINK);
+
+	/*
+	 * Can't flatten if it contains WITH.  (We could arrange to pull up the
+	 * WITH into the parent query's cteList, but that risks changing the
+	 * semantics, since a WITH ought to be executed once per associated query
+	 * call.)  Note that convert_ANY_sublink_to_join doesn't have to reject
+	 * this case, since it just produces a subquery RTE that doesn't have to
+	 * get flattened into the parent query.
+	 */
+	if (subselect->cteList)
+		return NULL;
+
+	/*
+	 * Copy the subquery so we can modify it safely (see comments in
+	 * make_subplan).
+	 */
+	subselect = copyObject(subselect);
+
+	/*
+	 * See if the subquery can be simplified based on the knowledge that it's
+	 * being used in EXISTS().  If we aren't able to get rid of its
+	 * targetlist, we have to fail, because the pullup operation leaves us
+	 * with noplace to evaluate the targetlist.
+	 */
+	if (!simplify_EXISTS_query(root, subselect))
+		return NULL;
+
+	/*
+	 * Separate out the WHERE clause.  (We could theoretically also remove
+	 * top-level plain JOIN/ON clauses, but it's probably not worth the
+	 * trouble.)
+	 */
+	whereClause = subselect->jointree->quals;
+	subselect->jointree->quals = NULL;
+
+	/*
+	 * The rest of the sub-select must not refer to any Vars of the parent
+	 * query.  (Vars of higher levels should be okay, though.)
+	 */
+	if (contain_vars_of_level((Node *) subselect, 1))
+		return NULL;
+
+	/*
+	 * On the other hand, the WHERE clause must contain some Vars of the
+	 * parent query, else it's not gonna be a join.
+	 */
+	if (!contain_vars_of_level(whereClause, 1))
+		return NULL;
+
+	/*
+	 * We don't risk optimizing if the WHERE clause is volatile, either.
+	 */
+	if (contain_volatile_functions(whereClause))
+		return NULL;
+
+	/*
+	 * The subquery must have a nonempty jointree, but we can make it so.
+	 */
+	replace_empty_jointree(subselect);
+
+	/*
+	 * Prepare to pull up the sub-select into top range table.
+	 *
+	 * We rely here on the assumption that the outer query has no references
+	 * to the inner (necessarily true). Therefore this is a lot easier than
+	 * what pull_up_subqueries has to go through.
+	 *
+	 * In fact, it's even easier than what convert_ANY_sublink_to_join has to
+	 * do.  The machinations of simplify_EXISTS_query ensured that there is
+	 * nothing interesting in the subquery except an rtable and jointree, and
+	 * even the jointree FromExpr no longer has quals.  So we can just append
+	 * the rtable to our own and use the FromExpr in our jointree. But first,
+	 * adjust all level-zero varnos in the subquery to account for the rtable
+	 * merger.
+	 */
+	rtoffset = list_length(parse->rtable);
+	OffsetVarNodes((Node *) subselect, rtoffset, 0);
+	OffsetVarNodes(whereClause, rtoffset, 0);
+
+	/*
+	 * Upper-level vars in subquery will now be one level closer to their
+	 * parent than before; in particular, anything that had been level 1
+	 * becomes level zero.
+	 */
+	IncrementVarSublevelsUp((Node *) subselect, -1, 1);
+	IncrementVarSublevelsUp(whereClause, -1, 1);
+
+	/*
+	 * Now that the WHERE clause is adjusted to match the parent query
+	 * environment, we can easily identify all the level-zero rels it uses.
+	 * The ones <= rtoffset belong to the upper query; the ones > rtoffset do
+	 * not.
+	 */
+	clause_varnos = pull_varnos(root, whereClause);
+	upper_varnos = NULL;
+	while ((varno = bms_first_member(clause_varnos)) >= 0)
+	{
+		if (varno <= rtoffset)
+			upper_varnos = bms_add_member(upper_varnos, varno);
+	}
+	bms_free(clause_varnos);
+	Assert(!bms_is_empty(upper_varnos));
+
+	/*
+	 * Now that we've got the set of upper-level varnos, we can make the last
+	 * check: only available_rels can be referenced.
+	 */
+	if (!bms_is_subset(upper_varnos, available_rels))
+		return NULL;
+
+	/* Now we can attach the modified subquery rtable to the parent */
+	parse->rtable = list_concat(parse->rtable, subselect->rtable);
+
+	/*
+	 * And finally, build the JoinExpr node.
+	 */
+	result = makeNode(JoinExpr);
+	result->jointype = under_not ? JOIN_ANTI : JOIN_SEMI;
+	result->isNatural = false;
+	result->larg = NULL;		/* caller must fill this in */
+	/* flatten out the FromExpr node if it's useless */
+	if (list_length(subselect->jointree->fromlist) == 1)
+		result->rarg = (Node *) linitial(subselect->jointree->fromlist);
+	else
+		result->rarg = (Node *) subselect->jointree;
+	result->usingClause = NIL;
+	result->join_using_alias = NULL;
+	result->quals = whereClause;
+	result->alias = NULL;
+	result->rtindex = 0;		/* we don't need an RTE for it */
+
+	return result;
+}
+
+/*
+ * simplify_EXISTS_query: remove any useless stuff in an EXISTS's subquery
+ *
+ * The only thing that matters about an EXISTS query is whether it returns
+ * zero or more than zero rows.  Therefore, we can remove certain SQL features
+ * that won't affect that.  The only part that is really likely to matter in
+ * typical usage is simplifying the targetlist: it's a common habit to write
+ * "SELECT * FROM" even though there is no need to evaluate any columns.
+ *
+ * Note: by suppressing the targetlist we could cause an observable behavioral
+ * change, namely that any errors that might occur in evaluating the tlist
+ * won't occur, nor will other side-effects of volatile functions.  This seems
+ * unlikely to bother anyone in practice.
+ *
+ * Returns true if was able to discard the targetlist, else false.
+ */
+static bool
+simplify_EXISTS_query(PlannerInfo *root, Query *query)
+{
+	/*
+	 * We don't try to simplify at all if the query uses set operations,
+	 * aggregates, grouping sets, SRFs, modifying CTEs, HAVING, OFFSET, or FOR
+	 * UPDATE/SHARE; none of these seem likely in normal usage and their
+	 * possible effects are complex.  (Note: we could ignore an "OFFSET 0"
+	 * clause, but that traditionally is used as an optimization fence, so we
+	 * don't.)
+	 */
+	if (query->commandType != CMD_SELECT ||
+		query->setOperations ||
+		query->hasAggs ||
+		query->groupingSets ||
+		query->hasWindowFuncs ||
+		query->hasTargetSRFs ||
+		query->hasModifyingCTE ||
+		query->havingQual ||
+		query->limitOffset ||
+		query->rowMarks)
+		return false;
+
+	/*
+	 * LIMIT with a constant positive (or NULL) value doesn't affect the
+	 * semantics of EXISTS, so let's ignore such clauses.  This is worth doing
+	 * because people accustomed to certain other DBMSes may be in the habit
+	 * of writing EXISTS(SELECT ... LIMIT 1) as an optimization.  If there's a
+	 * LIMIT with anything else as argument, though, we can't simplify.
+	 */
+	if (query->limitCount)
+	{
+		/*
+		 * The LIMIT clause has not yet been through eval_const_expressions,
+		 * so we have to apply that here.  It might seem like this is a waste
+		 * of cycles, since the only case plausibly worth worrying about is
+		 * "LIMIT 1" ... but what we'll actually see is "LIMIT int8(1::int4)",
+		 * so we have to fold constants or we're not going to recognize it.
+		 */
+		Node	   *node = eval_const_expressions(root, query->limitCount);
+		Const	   *limit;
+
+		/* Might as well update the query if we simplified the clause. */
+		query->limitCount = node;
+
+		if (!IsA(node, Const))
+			return false;
+
+		limit = (Const *) node;
+		Assert(limit->consttype == INT8OID);
+		if (!limit->constisnull && DatumGetInt64(limit->constvalue) <= 0)
+			return false;
+
+		/* Whether or not the targetlist is safe, we can drop the LIMIT. */
+		query->limitCount = NULL;
+	}
+
+	/*
+	 * Otherwise, we can throw away the targetlist, as well as any GROUP,
+	 * WINDOW, DISTINCT, and ORDER BY clauses; none of those clauses will
+	 * change a nonzero-rows result to zero rows or vice versa.  (Furthermore,
+	 * since our parsetree representation of these clauses depends on the
+	 * targetlist, we'd better throw them away if we drop the targetlist.)
+	 */
+	query->targetList = NIL;
+	query->groupClause = NIL;
+	query->windowClause = NIL;
+	query->distinctClause = NIL;
+	query->sortClause = NIL;
+	query->hasDistinctOn = false;
+
+	return true;
+}
+
+/*
+ * convert_EXISTS_to_ANY: try to convert EXISTS to a hashable ANY sublink
+ *
+ * The subselect is expected to be a fresh copy that we can munge up,
+ * and to have been successfully passed through simplify_EXISTS_query.
+ *
+ * On success, the modified subselect is returned, and we store a suitable
+ * upper-level test expression at *testexpr, plus a list of the subselect's
+ * output Params at *paramIds.  (The test expression is already Param-ified
+ * and hence need not go through convert_testexpr, which is why we have to
+ * deal with the Param IDs specially.)
+ *
+ * On failure, returns NULL.
+ */
+static Query *
+convert_EXISTS_to_ANY(PlannerInfo *root, Query *subselect,
+					  Node **testexpr, List **paramIds)
+{
+	Node	   *whereClause;
+	List	   *leftargs,
+			   *rightargs,
+			   *opids,
+			   *opcollations,
+			   *newWhere,
+			   *tlist,
+			   *testlist,
+			   *paramids;
+	ListCell   *lc,
+			   *rc,
+			   *oc,
+			   *cc;
+	AttrNumber	resno;
+
+	/*
+	 * Query must not require a targetlist, since we have to insert a new one.
+	 * Caller should have dealt with the case already.
+	 */
+	Assert(subselect->targetList == NIL);
+
+	/*
+	 * Separate out the WHERE clause.  (We could theoretically also remove
+	 * top-level plain JOIN/ON clauses, but it's probably not worth the
+	 * trouble.)
+	 */
+	whereClause = subselect->jointree->quals;
+	subselect->jointree->quals = NULL;
+
+	/*
+	 * The rest of the sub-select must not refer to any Vars of the parent
+	 * query.  (Vars of higher levels should be okay, though.)
+	 *
+	 * Note: we need not check for Aggrefs separately because we know the
+	 * sub-select is as yet unoptimized; any uplevel Aggref must therefore
+	 * contain an uplevel Var reference.  This is not the case below ...
+	 */
+	if (contain_vars_of_level((Node *) subselect, 1))
+		return NULL;
+
+	/*
+	 * We don't risk optimizing if the WHERE clause is volatile, either.
+	 */
+	if (contain_volatile_functions(whereClause))
+		return NULL;
+
+	/*
+	 * Clean up the WHERE clause by doing const-simplification etc on it.
+	 * Aside from simplifying the processing we're about to do, this is
+	 * important for being able to pull chunks of the WHERE clause up into the
+	 * parent query.  Since we are invoked partway through the parent's
+	 * preprocess_expression() work, earlier steps of preprocess_expression()
+	 * wouldn't get applied to the pulled-up stuff unless we do them here. For
+	 * the parts of the WHERE clause that get put back into the child query,
+	 * this work is partially duplicative, but it shouldn't hurt.
+	 *
+	 * Note: we do not run flatten_join_alias_vars.  This is OK because any
+	 * parent aliases were flattened already, and we're not going to pull any
+	 * child Vars (of any description) into the parent.
+	 *
+	 * Note: passing the parent's root to eval_const_expressions is
+	 * technically wrong, but we can get away with it since only the
+	 * boundParams (if any) are used, and those would be the same in a
+	 * subroot.
+	 */
+	whereClause = eval_const_expressions(root, whereClause);
+	whereClause = (Node *) canonicalize_qual((Expr *) whereClause, false);
+	whereClause = (Node *) make_ands_implicit((Expr *) whereClause);
+
+	/*
+	 * We now have a flattened implicit-AND list of clauses, which we try to
+	 * break apart into "outervar = innervar" hash clauses. Anything that
+	 * can't be broken apart just goes back into the newWhere list.  Note that
+	 * we aren't trying hard yet to ensure that we have only outer or only
+	 * inner on each side; we'll check that if we get to the end.
+	 */
+	leftargs = rightargs = opids = opcollations = newWhere = NIL;
+	foreach(lc, (List *) whereClause)
+	{
+		OpExpr	   *expr = (OpExpr *) lfirst(lc);
+
+		if (IsA(expr, OpExpr) &&
+			hash_ok_operator(expr))
+		{
+			Node	   *leftarg = (Node *) linitial(expr->args);
+			Node	   *rightarg = (Node *) lsecond(expr->args);
+
+			if (contain_vars_of_level(leftarg, 1))
+			{
+				leftargs = lappend(leftargs, leftarg);
+				rightargs = lappend(rightargs, rightarg);
+				opids = lappend_oid(opids, expr->opno);
+				opcollations = lappend_oid(opcollations, expr->inputcollid);
+				continue;
+			}
+			if (contain_vars_of_level(rightarg, 1))
+			{
+				/*
+				 * We must commute the clause to put the outer var on the
+				 * left, because the hashing code in nodeSubplan.c expects
+				 * that.  This probably shouldn't ever fail, since hashable
+				 * operators ought to have commutators, but be paranoid.
+				 */
+				expr->opno = get_commutator(expr->opno);
+				if (OidIsValid(expr->opno) && hash_ok_operator(expr))
+				{
+					leftargs = lappend(leftargs, rightarg);
+					rightargs = lappend(rightargs, leftarg);
+					opids = lappend_oid(opids, expr->opno);
+					opcollations = lappend_oid(opcollations, expr->inputcollid);
+					continue;
+				}
+				/* If no commutator, no chance to optimize the WHERE clause */
+				return NULL;
+			}
+		}
+		/* Couldn't handle it as a hash clause */
+		newWhere = lappend(newWhere, expr);
+	}
+
+	/*
+	 * If we didn't find anything we could convert, fail.
+	 */
+	if (leftargs == NIL)
+		return NULL;
+
+	/*
+	 * There mustn't be any parent Vars or Aggs in the stuff that we intend to
+	 * put back into the child query.  Note: you might think we don't need to
+	 * check for Aggs separately, because an uplevel Agg must contain an
+	 * uplevel Var in its argument.  But it is possible that the uplevel Var
+	 * got optimized away by eval_const_expressions.  Consider
+	 *
+	 * SUM(CASE WHEN false THEN uplevelvar ELSE 0 END)
+	 */
+	if (contain_vars_of_level((Node *) newWhere, 1) ||
+		contain_vars_of_level((Node *) rightargs, 1))
+		return NULL;
+	if (root->parse->hasAggs &&
+		(contain_aggs_of_level((Node *) newWhere, 1) ||
+		 contain_aggs_of_level((Node *) rightargs, 1)))
+		return NULL;
+
+	/*
+	 * And there can't be any child Vars in the stuff we intend to pull up.
+	 * (Note: we'd need to check for child Aggs too, except we know the child
+	 * has no aggs at all because of simplify_EXISTS_query's check. The same
+	 * goes for window functions.)
+	 */
+	if (contain_vars_of_level((Node *) leftargs, 0))
+		return NULL;
+
+	/*
+	 * Also reject sublinks in the stuff we intend to pull up.  (It might be
+	 * possible to support this, but doesn't seem worth the complication.)
+	 */
+	if (contain_subplans((Node *) leftargs))
+		return NULL;
+
+	/*
+	 * Okay, adjust the sublevelsup in the stuff we're pulling up.
+	 */
+	IncrementVarSublevelsUp((Node *) leftargs, -1, 1);
+
+	/*
+	 * Put back any child-level-only WHERE clauses.
+	 */
+	if (newWhere)
+		subselect->jointree->quals = (Node *) make_ands_explicit(newWhere);
+
+	/*
+	 * Build a new targetlist for the child that emits the expressions we
+	 * need.  Concurrently, build a testexpr for the parent using Params to
+	 * reference the child outputs.  (Since we generate Params directly here,
+	 * there will be no need to convert the testexpr in build_subplan.)
+	 */
+	tlist = testlist = paramids = NIL;
+	resno = 1;
+	forfour(lc, leftargs, rc, rightargs, oc, opids, cc, opcollations)
+	{
+		Node	   *leftarg = (Node *) lfirst(lc);
+		Node	   *rightarg = (Node *) lfirst(rc);
+		Oid			opid = lfirst_oid(oc);
+		Oid			opcollation = lfirst_oid(cc);
+		Param	   *param;
+
+		param = generate_new_exec_param(root,
+										exprType(rightarg),
+										exprTypmod(rightarg),
+										exprCollation(rightarg));
+		tlist = lappend(tlist,
+						makeTargetEntry((Expr *) rightarg,
+										resno++,
+										NULL,
+										false));
+		testlist = lappend(testlist,
+						   make_opclause(opid, BOOLOID, false,
+										 (Expr *) leftarg, (Expr *) param,
+										 InvalidOid, opcollation));
+		paramids = lappend_int(paramids, param->paramid);
+	}
+
+	/* Put everything where it should go, and we're done */
+	subselect->targetList = tlist;
+	*testexpr = (Node *) make_ands_explicit(testlist);
+	*paramIds = paramids;
+
+	return subselect;
+}
+
+
+/*
+ * Replace correlation vars (uplevel vars) with Params.
+ *
+ * Uplevel PlaceHolderVars and aggregates are replaced, too.
+ *
+ * Note: it is critical that this runs immediately after SS_process_sublinks.
+ * Since we do not recurse into the arguments of uplevel PHVs and aggregates,
+ * they will get copied to the appropriate subplan args list in the parent
+ * query with uplevel vars not replaced by Params, but only adjusted in level
+ * (see replace_outer_placeholdervar and replace_outer_agg).  That's exactly
+ * what we want for the vars of the parent level --- but if a PHV's or
+ * aggregate's argument contains any further-up variables, they have to be
+ * replaced with Params in their turn. That will happen when the parent level
+ * runs SS_replace_correlation_vars.  Therefore it must do so after expanding
+ * its sublinks to subplans.  And we don't want any steps in between, else
+ * those steps would never get applied to the argument expressions, either in
+ * the parent or the child level.
+ *
+ * Another fairly tricky thing going on here is the handling of SubLinks in
+ * the arguments of uplevel PHVs/aggregates.  Those are not touched inside the
+ * intermediate query level, either.  Instead, SS_process_sublinks recurses on
+ * them after copying the PHV or Aggref expression into the parent plan level
+ * (this is actually taken care of in build_subplan).
+ */
+Node *
+SS_replace_correlation_vars(PlannerInfo *root, Node *expr)
+{
+	/* No setup needed for tree walk, so away we go */
+	return replace_correlation_vars_mutator(expr, root);
+}
+
+static Node *
+replace_correlation_vars_mutator(Node *node, PlannerInfo *root)
+{
+	if (node == NULL)
+		return NULL;
+	if (IsA(node, Var))
+	{
+		if (((Var *) node)->varlevelsup > 0)
+			return (Node *) replace_outer_var(root, (Var *) node);
+	}
+	if (IsA(node, PlaceHolderVar))
+	{
+		if (((PlaceHolderVar *) node)->phlevelsup > 0)
+			return (Node *) replace_outer_placeholdervar(root,
+														 (PlaceHolderVar *) node);
+	}
+	if (IsA(node, Aggref))
+	{
+		if (((Aggref *) node)->agglevelsup > 0)
+			return (Node *) replace_outer_agg(root, (Aggref *) node);
+	}
+	if (IsA(node, GroupingFunc))
+	{
+		if (((GroupingFunc *) node)->agglevelsup > 0)
+			return (Node *) replace_outer_grouping(root, (GroupingFunc *) node);
+	}
+	return expression_tree_mutator(node,
+								   replace_correlation_vars_mutator,
+								   (void *) root);
+}
+
+/*
+ * Expand SubLinks to SubPlans in the given expression.
+ *
+ * The isQual argument tells whether or not this expression is a WHERE/HAVING
+ * qualifier expression.  If it is, any sublinks appearing at top level need
+ * not distinguish FALSE from UNKNOWN return values.
+ */
+Node *
+SS_process_sublinks(PlannerInfo *root, Node *expr, bool isQual)
+{
+	process_sublinks_context context;
+
+	context.root = root;
+	context.isTopQual = isQual;
+	return process_sublinks_mutator(expr, &context);
+}
+
+static Node *
+process_sublinks_mutator(Node *node, process_sublinks_context *context)
+{
+	process_sublinks_context locContext;
+
+	locContext.root = context->root;
+
+	if (node == NULL)
+		return NULL;
+	if (IsA(node, SubLink))
+	{
+		SubLink    *sublink = (SubLink *) node;
+		Node	   *testexpr;
+
+		/*
+		 * First, recursively process the lefthand-side expressions, if any.
+		 * They're not top-level anymore.
+		 */
+		locContext.isTopQual = false;
+		testexpr = process_sublinks_mutator(sublink->testexpr, &locContext);
+
+		/*
+		 * Now build the SubPlan node and make the expr to return.
+		 */
+		return make_subplan(context->root,
+							(Query *) sublink->subselect,
+							sublink->subLinkType,
+							sublink->subLinkId,
+							testexpr,
+							context->isTopQual);
+	}
+
+	/*
+	 * Don't recurse into the arguments of an outer PHV, Aggref or
+	 * GroupingFunc here.  Any SubLinks in the arguments have to be dealt with
+	 * at the outer query level; they'll be handled when build_subplan
+	 * collects the PHV, Aggref or GroupingFunc into the arguments to be
+	 * passed down to the current subplan.
+	 */
+	if (IsA(node, PlaceHolderVar))
+	{
+		if (((PlaceHolderVar *) node)->phlevelsup > 0)
+			return node;
+	}
+	else if (IsA(node, Aggref))
+	{
+		if (((Aggref *) node)->agglevelsup > 0)
+			return node;
+	}
+	else if (IsA(node, GroupingFunc))
+	{
+		if (((GroupingFunc *) node)->agglevelsup > 0)
+			return node;
+	}
+
+	/*
+	 * We should never see a SubPlan expression in the input (since this is
+	 * the very routine that creates 'em to begin with).  We shouldn't find
+	 * ourselves invoked directly on a Query, either.
+	 */
+	Assert(!IsA(node, SubPlan));
+	Assert(!IsA(node, AlternativeSubPlan));
+	Assert(!IsA(node, Query));
+
+	/*
+	 * Because make_subplan() could return an AND or OR clause, we have to
+	 * take steps to preserve AND/OR flatness of a qual.  We assume the input
+	 * has been AND/OR flattened and so we need no recursion here.
+	 *
+	 * (Due to the coding here, we will not get called on the List subnodes of
+	 * an AND; and the input is *not* yet in implicit-AND format.  So no check
+	 * is needed for a bare List.)
+	 *
+	 * Anywhere within the top-level AND/OR clause structure, we can tell
+	 * make_subplan() that NULL and FALSE are interchangeable.  So isTopQual
+	 * propagates down in both cases.  (Note that this is unlike the meaning
+	 * of "top level qual" used in most other places in Postgres.)
+	 */
+	if (is_andclause(node))
+	{
+		List	   *newargs = NIL;
+		ListCell   *l;
+
+		/* Still at qual top-level */
+		locContext.isTopQual = context->isTopQual;
+
+		foreach(l, ((BoolExpr *) node)->args)
+		{
+			Node	   *newarg;
+
+			newarg = process_sublinks_mutator(lfirst(l), &locContext);
+			if (is_andclause(newarg))
+				newargs = list_concat(newargs, ((BoolExpr *) newarg)->args);
+			else
+				newargs = lappend(newargs, newarg);
+		}
+		return (Node *) make_andclause(newargs);
+	}
+
+	if (is_orclause(node))
+	{
+		List	   *newargs = NIL;
+		ListCell   *l;
+
+		/* Still at qual top-level */
+		locContext.isTopQual = context->isTopQual;
+
+		foreach(l, ((BoolExpr *) node)->args)
+		{
+			Node	   *newarg;
+
+			newarg = process_sublinks_mutator(lfirst(l), &locContext);
+			if (is_orclause(newarg))
+				newargs = list_concat(newargs, ((BoolExpr *) newarg)->args);
+			else
+				newargs = lappend(newargs, newarg);
+		}
+		return (Node *) make_orclause(newargs);
+	}
+
+	/*
+	 * If we recurse down through anything other than an AND or OR node, we
+	 * are definitely not at top qual level anymore.
+	 */
+	locContext.isTopQual = false;
+
+	return expression_tree_mutator(node,
+								   process_sublinks_mutator,
+								   (void *) &locContext);
+}
+
+/*
+ * SS_identify_outer_params - identify the Params available from outer levels
+ *
+ * This must be run after SS_replace_correlation_vars and SS_process_sublinks
+ * processing is complete in a given query level as well as all of its
+ * descendant levels (which means it's most practical to do it at the end of
+ * processing the query level).  We compute the set of paramIds that outer
+ * levels will make available to this level+descendants, and record it in
+ * root->outer_params for use while computing extParam/allParam sets in final
+ * plan cleanup.  (We can't just compute it then, because the upper levels'
+ * plan_params lists are transient and will be gone by then.)
+ */
+void
+SS_identify_outer_params(PlannerInfo *root)
+{
+	Bitmapset  *outer_params;
+	PlannerInfo *proot;
+	ListCell   *l;
+
+	/*
+	 * If no parameters have been assigned anywhere in the tree, we certainly
+	 * don't need to do anything here.
+	 */
+	if (root->glob->paramExecTypes == NIL)
+		return;
+
+	/*
+	 * Scan all query levels above this one to see which parameters are due to
+	 * be available from them, either because lower query levels have
+	 * requested them (via plan_params) or because they will be available from
+	 * initPlans of those levels.
+	 */
+	outer_params = NULL;
+	for (proot = root->parent_root; proot != NULL; proot = proot->parent_root)
+	{
+		/* Include ordinary Var/PHV/Aggref/GroupingFunc params */
+		foreach(l, proot->plan_params)
+		{
+			PlannerParamItem *pitem = (PlannerParamItem *) lfirst(l);
+
+			outer_params = bms_add_member(outer_params, pitem->paramId);
+		}
+		/* Include any outputs of outer-level initPlans */
+		foreach(l, proot->init_plans)
+		{
+			SubPlan    *initsubplan = (SubPlan *) lfirst(l);
+			ListCell   *l2;
+
+			foreach(l2, initsubplan->setParam)
+			{
+				outer_params = bms_add_member(outer_params, lfirst_int(l2));
+			}
+		}
+		/* Include worktable ID, if a recursive query is being planned */
+		if (proot->wt_param_id >= 0)
+			outer_params = bms_add_member(outer_params, proot->wt_param_id);
+	}
+	root->outer_params = outer_params;
+}
+
+/*
+ * SS_charge_for_initplans - account for initplans in Path costs & parallelism
+ *
+ * If any initPlans have been created in the current query level, they will
+ * get attached to the Plan tree created from whichever Path we select from
+ * the given rel.  Increment all that rel's Paths' costs to account for them,
+ * and make sure the paths get marked as parallel-unsafe, since we can't
+ * currently transmit initPlans to parallel workers.
+ *
+ * This is separate from SS_attach_initplans because we might conditionally
+ * create more initPlans during create_plan(), depending on which Path we
+ * select.  However, Paths that would generate such initPlans are expected
+ * to have included their cost already.
+ */
+void
+SS_charge_for_initplans(PlannerInfo *root, RelOptInfo *final_rel)
+{
+	Cost		initplan_cost;
+	ListCell   *lc;
+
+	/* Nothing to do if no initPlans */
+	if (root->init_plans == NIL)
+		return;
+
+	/*
+	 * Compute the cost increment just once, since it will be the same for all
+	 * Paths.  We assume each initPlan gets run once during top plan startup.
+	 * This is a conservative overestimate, since in fact an initPlan might be
+	 * executed later than plan startup, or even not at all.
+	 */
+	initplan_cost = 0;
+	foreach(lc, root->init_plans)
+	{
+		SubPlan    *initsubplan = (SubPlan *) lfirst(lc);
+
+		initplan_cost += initsubplan->startup_cost + initsubplan->per_call_cost;
+	}
+
+	/*
+	 * Now adjust the costs and parallel_safe flags.
+	 */
+	foreach(lc, final_rel->pathlist)
+	{
+		Path	   *path = (Path *) lfirst(lc);
+
+		path->startup_cost += initplan_cost;
+		path->total_cost += initplan_cost;
+		path->parallel_safe = false;
+	}
+
+	/*
+	 * Forget about any partial paths and clear consider_parallel, too;
+	 * they're not usable if we attached an initPlan.
+	 */
+	final_rel->partial_pathlist = NIL;
+	final_rel->consider_parallel = false;
+
+	/* We needn't do set_cheapest() here, caller will do it */
+}
+
+/*
+ * SS_attach_initplans - attach initplans to topmost plan node
+ *
+ * Attach any initplans created in the current query level to the specified
+ * plan node, which should normally be the topmost node for the query level.
+ * (In principle the initPlans could go in any node at or above where they're
+ * referenced; but there seems no reason to put them any lower than the
+ * topmost node, so we don't bother to track exactly where they came from.)
+ * We do not touch the plan node's cost; the initplans should have been
+ * accounted for in path costing.
+ */
+void
+SS_attach_initplans(PlannerInfo *root, Plan *plan)
+{
+	plan->initPlan = root->init_plans;
+}
+
+/*
+ * SS_finalize_plan - do final parameter processing for a completed Plan.
+ *
+ * This recursively computes the extParam and allParam sets for every Plan
+ * node in the given plan tree.  (Oh, and RangeTblFunction.funcparams too.)
+ *
+ * We assume that SS_finalize_plan has already been run on any initplans or
+ * subplans the plan tree could reference.
+ */
+void
+SS_finalize_plan(PlannerInfo *root, Plan *plan)
+{
+	/* No setup needed, just recurse through plan tree. */
+	(void) finalize_plan(root, plan, -1, root->outer_params, NULL);
+}
+
+/*
+ * Recursive processing of all nodes in the plan tree
+ *
+ * gather_param is the rescan_param of an ancestral Gather/GatherMerge,
+ * or -1 if there is none.
+ *
+ * valid_params is the set of param IDs supplied by outer plan levels
+ * that are valid to reference in this plan node or its children.
+ *
+ * scan_params is a set of param IDs to force scan plan nodes to reference.
+ * This is for EvalPlanQual support, and is always NULL at the top of the
+ * recursion.
+ *
+ * The return value is the computed allParam set for the given Plan node.
+ * This is just an internal notational convenience: we can add a child
+ * plan's allParams to the set of param IDs of interest to this level
+ * in the same statement that recurses to that child.
+ *
+ * Do not scribble on caller's values of valid_params or scan_params!
+ *
+ * Note: although we attempt to deal with initPlans anywhere in the tree, the
+ * logic is not really right.  The problem is that a plan node might return an
+ * output Param of its initPlan as a targetlist item, in which case it's valid
+ * for the parent plan level to reference that same Param; the parent's usage
+ * will be converted into a Var referencing the child plan node by setrefs.c.
+ * But this function would see the parent's reference as out of scope and
+ * complain about it.  For now, this does not matter because the planner only
+ * attaches initPlans to the topmost plan node in a query level, so the case
+ * doesn't arise.  If we ever merge this processing into setrefs.c, maybe it
+ * can be handled more cleanly.
+ */
+static Bitmapset *
+finalize_plan(PlannerInfo *root, Plan *plan,
+			  int gather_param,
+			  Bitmapset *valid_params,
+			  Bitmapset *scan_params)
+{
+	finalize_primnode_context context;
+	int			locally_added_param;
+	Bitmapset  *nestloop_params;
+	Bitmapset  *initExtParam;
+	Bitmapset  *initSetParam;
+	Bitmapset  *child_params;
+	ListCell   *l;
+
+	if (plan == NULL)
+		return NULL;
+
+	context.root = root;
+	context.paramids = NULL;	/* initialize set to empty */
+	locally_added_param = -1;	/* there isn't one */
+	nestloop_params = NULL;		/* there aren't any */
+
+	/*
+	 * Examine any initPlans to determine the set of external params they
+	 * reference and the set of output params they supply.  (We assume
+	 * SS_finalize_plan was run on them already.)
+	 */
+	initExtParam = initSetParam = NULL;
+	foreach(l, plan->initPlan)
+	{
+		SubPlan    *initsubplan = (SubPlan *) lfirst(l);
+		Plan	   *initplan = planner_subplan_get_plan(root, initsubplan);
+		ListCell   *l2;
+
+		initExtParam = bms_add_members(initExtParam, initplan->extParam);
+		foreach(l2, initsubplan->setParam)
+		{
+			initSetParam = bms_add_member(initSetParam, lfirst_int(l2));
+		}
+	}
+
+	/* Any setParams are validly referenceable in this node and children */
+	if (initSetParam)
+		valid_params = bms_union(valid_params, initSetParam);
+
+	/*
+	 * When we call finalize_primnode, context.paramids sets are automatically
+	 * merged together.  But when recursing to self, we have to do it the hard
+	 * way.  We want the paramids set to include params in subplans as well as
+	 * at this level.
+	 */
+
+	/* Find params in targetlist and qual */
+	finalize_primnode((Node *) plan->targetlist, &context);
+	finalize_primnode((Node *) plan->qual, &context);
+
+	/*
+	 * If it's a parallel-aware scan node, mark it as dependent on the parent
+	 * Gather/GatherMerge's rescan Param.
+	 */
+	if (plan->parallel_aware)
+	{
+		if (gather_param < 0)
+			elog(ERROR, "parallel-aware plan node is not below a Gather");
+		context.paramids =
+			bms_add_member(context.paramids, gather_param);
+	}
+
+	/* Check additional node-type-specific fields */
+	switch (nodeTag(plan))
+	{
+		case T_Result:
+			finalize_primnode(((Result *) plan)->resconstantqual,
+							  &context);
+			break;
+
+		case T_SeqScan:
+			context.paramids = bms_add_members(context.paramids, scan_params);
+			break;
+
+		case T_SampleScan:
+			finalize_primnode((Node *) ((SampleScan *) plan)->tablesample,
+							  &context);
+			context.paramids = bms_add_members(context.paramids, scan_params);
+			break;
+
+		case T_IndexScan:
+			finalize_primnode((Node *) ((IndexScan *) plan)->indexqual,
+							  &context);
+			finalize_primnode((Node *) ((IndexScan *) plan)->indexorderby,
+							  &context);
+
+			/*
+			 * we need not look at indexqualorig, since it will have the same
+			 * param references as indexqual.  Likewise, we can ignore
+			 * indexorderbyorig.
+			 */
+			context.paramids = bms_add_members(context.paramids, scan_params);
+			break;
+
+		case T_IndexOnlyScan:
+			finalize_primnode((Node *) ((IndexOnlyScan *) plan)->indexqual,
+							  &context);
+			finalize_primnode((Node *) ((IndexOnlyScan *) plan)->recheckqual,
+							  &context);
+			finalize_primnode((Node *) ((IndexOnlyScan *) plan)->indexorderby,
+							  &context);
+
+			/*
+			 * we need not look at indextlist, since it cannot contain Params.
+			 */
+			context.paramids = bms_add_members(context.paramids, scan_params);
+			break;
+
+		case T_BitmapIndexScan:
+			finalize_primnode((Node *) ((BitmapIndexScan *) plan)->indexqual,
+							  &context);
+
+			/*
+			 * we need not look at indexqualorig, since it will have the same
+			 * param references as indexqual.
+			 */
+			break;
+
+		case T_BitmapHeapScan:
+			finalize_primnode((Node *) ((BitmapHeapScan *) plan)->bitmapqualorig,
+							  &context);
+			context.paramids = bms_add_members(context.paramids, scan_params);
+			break;
+
+		case T_TidScan:
+			finalize_primnode((Node *) ((TidScan *) plan)->tidquals,
+							  &context);
+			context.paramids = bms_add_members(context.paramids, scan_params);
+			break;
+
+		case T_TidRangeScan:
+			finalize_primnode((Node *) ((TidRangeScan *) plan)->tidrangequals,
+							  &context);
+			context.paramids = bms_add_members(context.paramids, scan_params);
+			break;
+
+		case T_SubqueryScan:
+			{
+				SubqueryScan *sscan = (SubqueryScan *) plan;
+				RelOptInfo *rel;
+				Bitmapset  *subquery_params;
+
+				/* We must run finalize_plan on the subquery */
+				rel = find_base_rel(root, sscan->scan.scanrelid);
+				subquery_params = rel->subroot->outer_params;
+				if (gather_param >= 0)
+					subquery_params = bms_add_member(bms_copy(subquery_params),
+													 gather_param);
+				finalize_plan(rel->subroot, sscan->subplan, gather_param,
+							  subquery_params, NULL);
+
+				/* Now we can add its extParams to the parent's params */
+				context.paramids = bms_add_members(context.paramids,
+												   sscan->subplan->extParam);
+				/* We need scan_params too, though */
+				context.paramids = bms_add_members(context.paramids,
+												   scan_params);
+			}
+			break;
+
+		case T_FunctionScan:
+			{
+				FunctionScan *fscan = (FunctionScan *) plan;
+				ListCell   *lc;
+
+				/*
+				 * Call finalize_primnode independently on each function
+				 * expression, so that we can record which params are
+				 * referenced in each, in order to decide which need
+				 * re-evaluating during rescan.
+				 */
+				foreach(lc, fscan->functions)
+				{
+					RangeTblFunction *rtfunc = (RangeTblFunction *) lfirst(lc);
+					finalize_primnode_context funccontext;
+
+					funccontext = context;
+					funccontext.paramids = NULL;
+
+					finalize_primnode(rtfunc->funcexpr, &funccontext);
+
+					/* remember results for execution */
+					rtfunc->funcparams = funccontext.paramids;
+
+					/* add the function's params to the overall set */
+					context.paramids = bms_add_members(context.paramids,
+													   funccontext.paramids);
+				}
+
+				context.paramids = bms_add_members(context.paramids,
+												   scan_params);
+			}
+			break;
+
+		case T_TableFuncScan:
+			finalize_primnode((Node *) ((TableFuncScan *) plan)->tablefunc,
+							  &context);
+			context.paramids = bms_add_members(context.paramids, scan_params);
+			break;
+
+		case T_ValuesScan:
+			finalize_primnode((Node *) ((ValuesScan *) plan)->values_lists,
+							  &context);
+			context.paramids = bms_add_members(context.paramids, scan_params);
+			break;
+
+		case T_CteScan:
+			{
+				/*
+				 * You might think we should add the node's cteParam to
+				 * paramids, but we shouldn't because that param is just a
+				 * linkage mechanism for multiple CteScan nodes for the same
+				 * CTE; it is never used for changed-param signaling.  What we
+				 * have to do instead is to find the referenced CTE plan and
+				 * incorporate its external paramids, so that the correct
+				 * things will happen if the CTE references outer-level
+				 * variables.  See test cases for bug #4902.  (We assume
+				 * SS_finalize_plan was run on the CTE plan already.)
+				 */
+				int			plan_id = ((CteScan *) plan)->ctePlanId;
+				Plan	   *cteplan;
+
+				/* so, do this ... */
+				if (plan_id < 1 || plan_id > list_length(root->glob->subplans))
+					elog(ERROR, "could not find plan for CteScan referencing plan ID %d",
+						 plan_id);
+				cteplan = (Plan *) list_nth(root->glob->subplans, plan_id - 1);
+				context.paramids =
+					bms_add_members(context.paramids, cteplan->extParam);
+
+#ifdef NOT_USED
+				/* ... but not this */
+				context.paramids =
+					bms_add_member(context.paramids,
+								   ((CteScan *) plan)->cteParam);
+#endif
+
+				context.paramids = bms_add_members(context.paramids,
+												   scan_params);
+			}
+			break;
+
+		case T_WorkTableScan:
+			context.paramids =
+				bms_add_member(context.paramids,
+							   ((WorkTableScan *) plan)->wtParam);
+			context.paramids = bms_add_members(context.paramids, scan_params);
+			break;
+
+		case T_NamedTuplestoreScan:
+			context.paramids = bms_add_members(context.paramids, scan_params);
+			break;
+
+		case T_ForeignScan:
+			{
+				ForeignScan *fscan = (ForeignScan *) plan;
+
+				finalize_primnode((Node *) fscan->fdw_exprs,
+								  &context);
+				finalize_primnode((Node *) fscan->fdw_recheck_quals,
+								  &context);
+
+				/* We assume fdw_scan_tlist cannot contain Params */
+				context.paramids = bms_add_members(context.paramids,
+												   scan_params);
+			}
+			break;
+
+		case T_CustomScan:
+			{
+				CustomScan *cscan = (CustomScan *) plan;
+				ListCell   *lc;
+
+				finalize_primnode((Node *) cscan->custom_exprs,
+								  &context);
+				/* We assume custom_scan_tlist cannot contain Params */
+				context.paramids =
+					bms_add_members(context.paramids, scan_params);
+
+				/* child nodes if any */
+				foreach(lc, cscan->custom_plans)
+				{
+					context.paramids =
+						bms_add_members(context.paramids,
+										finalize_plan(root,
+													  (Plan *) lfirst(lc),
+													  gather_param,
+													  valid_params,
+													  scan_params));
+				}
+			}
+			break;
+
+		case T_ModifyTable:
+			{
+				ModifyTable *mtplan = (ModifyTable *) plan;
+
+				/* Force descendant scan nodes to reference epqParam */
+				locally_added_param = mtplan->epqParam;
+				valid_params = bms_add_member(bms_copy(valid_params),
+											  locally_added_param);
+				scan_params = bms_add_member(bms_copy(scan_params),
+											 locally_added_param);
+				finalize_primnode((Node *) mtplan->returningLists,
+								  &context);
+				finalize_primnode((Node *) mtplan->onConflictSet,
+								  &context);
+				finalize_primnode((Node *) mtplan->onConflictWhere,
+								  &context);
+				/* exclRelTlist contains only Vars, doesn't need examination */
+			}
+			break;
+
+		case T_Append:
+			{
+				ListCell   *l;
+
+				foreach(l, ((Append *) plan)->appendplans)
+				{
+					context.paramids =
+						bms_add_members(context.paramids,
+										finalize_plan(root,
+													  (Plan *) lfirst(l),
+													  gather_param,
+													  valid_params,
+													  scan_params));
+				}
+			}
+			break;
+
+		case T_MergeAppend:
+			{
+				ListCell   *l;
+
+				foreach(l, ((MergeAppend *) plan)->mergeplans)
+				{
+					context.paramids =
+						bms_add_members(context.paramids,
+										finalize_plan(root,
+													  (Plan *) lfirst(l),
+													  gather_param,
+													  valid_params,
+													  scan_params));
+				}
+			}
+			break;
+
+		case T_BitmapAnd:
+			{
+				ListCell   *l;
+
+				foreach(l, ((BitmapAnd *) plan)->bitmapplans)
+				{
+					context.paramids =
+						bms_add_members(context.paramids,
+										finalize_plan(root,
+													  (Plan *) lfirst(l),
+													  gather_param,
+													  valid_params,
+													  scan_params));
+				}
+			}
+			break;
+
+		case T_BitmapOr:
+			{
+				ListCell   *l;
+
+				foreach(l, ((BitmapOr *) plan)->bitmapplans)
+				{
+					context.paramids =
+						bms_add_members(context.paramids,
+										finalize_plan(root,
+													  (Plan *) lfirst(l),
+													  gather_param,
+													  valid_params,
+													  scan_params));
+				}
+			}
+			break;
+
+		case T_NestLoop:
+			{
+				ListCell   *l;
+
+				finalize_primnode((Node *) ((Join *) plan)->joinqual,
+								  &context);
+				/* collect set of params that will be passed to right child */
+				foreach(l, ((NestLoop *) plan)->nestParams)
+				{
+					NestLoopParam *nlp = (NestLoopParam *) lfirst(l);
+
+					nestloop_params = bms_add_member(nestloop_params,
+													 nlp->paramno);
+				}
+			}
+			break;
+
+		case T_MergeJoin:
+			finalize_primnode((Node *) ((Join *) plan)->joinqual,
+							  &context);
+			finalize_primnode((Node *) ((MergeJoin *) plan)->mergeclauses,
+							  &context);
+			break;
+
+		case T_HashJoin:
+			finalize_primnode((Node *) ((Join *) plan)->joinqual,
+							  &context);
+			finalize_primnode((Node *) ((HashJoin *) plan)->hashclauses,
+							  &context);
+			break;
+
+		case T_Limit:
+			finalize_primnode(((Limit *) plan)->limitOffset,
+							  &context);
+			finalize_primnode(((Limit *) plan)->limitCount,
+							  &context);
+			break;
+
+		case T_RecursiveUnion:
+			/* child nodes are allowed to reference wtParam */
+			locally_added_param = ((RecursiveUnion *) plan)->wtParam;
+			valid_params = bms_add_member(bms_copy(valid_params),
+										  locally_added_param);
+			/* wtParam does *not* get added to scan_params */
+			break;
+
+		case T_LockRows:
+			/* Force descendant scan nodes to reference epqParam */
+			locally_added_param = ((LockRows *) plan)->epqParam;
+			valid_params = bms_add_member(bms_copy(valid_params),
+										  locally_added_param);
+			scan_params = bms_add_member(bms_copy(scan_params),
+										 locally_added_param);
+			break;
+
+		case T_Agg:
+			{
+				Agg		   *agg = (Agg *) plan;
+
+				/*
+				 * AGG_HASHED plans need to know which Params are referenced
+				 * in aggregate calls.  Do a separate scan to identify them.
+				 */
+				if (agg->aggstrategy == AGG_HASHED)
+				{
+					finalize_primnode_context aggcontext;
+
+					aggcontext.root = root;
+					aggcontext.paramids = NULL;
+					finalize_agg_primnode((Node *) agg->plan.targetlist,
+										  &aggcontext);
+					finalize_agg_primnode((Node *) agg->plan.qual,
+										  &aggcontext);
+					agg->aggParams = aggcontext.paramids;
+				}
+			}
+			break;
+
+		case T_WindowAgg:
+			finalize_primnode(((WindowAgg *) plan)->startOffset,
+							  &context);
+			finalize_primnode(((WindowAgg *) plan)->endOffset,
+							  &context);
+			break;
+
+		case T_Gather:
+			/* child nodes are allowed to reference rescan_param, if any */
+			locally_added_param = ((Gather *) plan)->rescan_param;
+			if (locally_added_param >= 0)
+			{
+				valid_params = bms_add_member(bms_copy(valid_params),
+											  locally_added_param);
+
+				/*
+				 * We currently don't support nested Gathers.  The issue so
+				 * far as this function is concerned would be how to identify
+				 * which child nodes depend on which Gather.
+				 */
+				Assert(gather_param < 0);
+				/* Pass down rescan_param to child parallel-aware nodes */
+				gather_param = locally_added_param;
+			}
+			/* rescan_param does *not* get added to scan_params */
+			break;
+
+		case T_GatherMerge:
+			/* child nodes are allowed to reference rescan_param, if any */
+			locally_added_param = ((GatherMerge *) plan)->rescan_param;
+			if (locally_added_param >= 0)
+			{
+				valid_params = bms_add_member(bms_copy(valid_params),
+											  locally_added_param);
+
+				/*
+				 * We currently don't support nested Gathers.  The issue so
+				 * far as this function is concerned would be how to identify
+				 * which child nodes depend on which Gather.
+				 */
+				Assert(gather_param < 0);
+				/* Pass down rescan_param to child parallel-aware nodes */
+				gather_param = locally_added_param;
+			}
+			/* rescan_param does *not* get added to scan_params */
+			break;
+
+		case T_Memoize:
+			finalize_primnode((Node *) ((Memoize *) plan)->param_exprs,
+							  &context);
+			break;
+
+		case T_ProjectSet:
+		case T_Hash:
+		case T_Material:
+		case T_Sort:
+		case T_IncrementalSort:
+		case T_Unique:
+		case T_SetOp:
+		case T_Group:
+			/* no node-type-specific fields need fixing */
+			break;
+
+		default:
+			elog(ERROR, "unrecognized node type: %d",
+				 (int) nodeTag(plan));
+	}
+
+	/* Process left and right child plans, if any */
+	child_params = finalize_plan(root,
+								 plan->lefttree,
+								 gather_param,
+								 valid_params,
+								 scan_params);
+	context.paramids = bms_add_members(context.paramids, child_params);
+
+	if (nestloop_params)
+	{
+		/* right child can reference nestloop_params as well as valid_params */
+		child_params = finalize_plan(root,
+									 plan->righttree,
+									 gather_param,
+									 bms_union(nestloop_params, valid_params),
+									 scan_params);
+		/* ... and they don't count as parameters used at my level */
+		child_params = bms_difference(child_params, nestloop_params);
+		bms_free(nestloop_params);
+	}
+	else
+	{
+		/* easy case */
+		child_params = finalize_plan(root,
+									 plan->righttree,
+									 gather_param,
+									 valid_params,
+									 scan_params);
+	}
+	context.paramids = bms_add_members(context.paramids, child_params);
+
+	/*
+	 * Any locally generated parameter doesn't count towards its generating
+	 * plan node's external dependencies.  (Note: if we changed valid_params
+	 * and/or scan_params, we leak those bitmapsets; not worth the notational
+	 * trouble to clean them up.)
+	 */
+	if (locally_added_param >= 0)
+	{
+		context.paramids = bms_del_member(context.paramids,
+										  locally_added_param);
+	}
+
+	/* Now we have all the paramids referenced in this node and children */
+
+	if (!bms_is_subset(context.paramids, valid_params))
+		elog(ERROR, "plan should not reference subplan's variable");
+
+	/*
+	 * The plan node's allParam and extParam fields should include all its
+	 * referenced paramids, plus contributions from any child initPlans.
+	 * However, any setParams of the initPlans should not be present in the
+	 * parent node's extParams, only in its allParams.  (It's possible that
+	 * some initPlans have extParams that are setParams of other initPlans.)
+	 */
+
+	/* allParam must include initplans' extParams and setParams */
+	plan->allParam = bms_union(context.paramids, initExtParam);
+	plan->allParam = bms_add_members(plan->allParam, initSetParam);
+	/* extParam must include any initplan extParams */
+	plan->extParam = bms_union(context.paramids, initExtParam);
+	/* but not any initplan setParams */
+	plan->extParam = bms_del_members(plan->extParam, initSetParam);
+
+	/*
+	 * For speed at execution time, make sure extParam/allParam are actually
+	 * NULL if they are empty sets.
+	 */
+	if (bms_is_empty(plan->extParam))
+		plan->extParam = NULL;
+	if (bms_is_empty(plan->allParam))
+		plan->allParam = NULL;
+
+	return plan->allParam;
+}
+
+/*
+ * finalize_primnode: add IDs of all PARAM_EXEC params appearing in the given
+ * expression tree to the result set.
+ */
+static bool
+finalize_primnode(Node *node, finalize_primnode_context *context)
+{
+	if (node == NULL)
+		return false;
+	if (IsA(node, Param))
+	{
+		if (((Param *) node)->paramkind == PARAM_EXEC)
+		{
+			int			paramid = ((Param *) node)->paramid;
+
+			context->paramids = bms_add_member(context->paramids, paramid);
+		}
+		return false;			/* no more to do here */
+	}
+	if (IsA(node, SubPlan))
+	{
+		SubPlan    *subplan = (SubPlan *) node;
+		Plan	   *plan = planner_subplan_get_plan(context->root, subplan);
+		ListCell   *lc;
+		Bitmapset  *subparamids;
+
+		/* Recurse into the testexpr, but not into the Plan */
+		finalize_primnode(subplan->testexpr, context);
+
+		/*
+		 * Remove any param IDs of output parameters of the subplan that were
+		 * referenced in the testexpr.  These are not interesting for
+		 * parameter change signaling since we always re-evaluate the subplan.
+		 * Note that this wouldn't work too well if there might be uses of the
+		 * same param IDs elsewhere in the plan, but that can't happen because
+		 * generate_new_exec_param never tries to merge params.
+		 */
+		foreach(lc, subplan->paramIds)
+		{
+			context->paramids = bms_del_member(context->paramids,
+											   lfirst_int(lc));
+		}
+
+		/* Also examine args list */
+		finalize_primnode((Node *) subplan->args, context);
+
+		/*
+		 * Add params needed by the subplan to paramids, but excluding those
+		 * we will pass down to it.  (We assume SS_finalize_plan was run on
+		 * the subplan already.)
+		 */
+		subparamids = bms_copy(plan->extParam);
+		foreach(lc, subplan->parParam)
+		{
+			subparamids = bms_del_member(subparamids, lfirst_int(lc));
+		}
+		context->paramids = bms_join(context->paramids, subparamids);
+
+		return false;			/* no more to do here */
+	}
+	return expression_tree_walker(node, finalize_primnode,
+								  (void *) context);
+}
+
+/*
+ * finalize_agg_primnode: find all Aggref nodes in the given expression tree,
+ * and add IDs of all PARAM_EXEC params appearing within their aggregated
+ * arguments to the result set.
+ */
+static bool
+finalize_agg_primnode(Node *node, finalize_primnode_context *context)
+{
+	if (node == NULL)
+		return false;
+	if (IsA(node, Aggref))
+	{
+		Aggref	   *agg = (Aggref *) node;
+
+		/* we should not consider the direct arguments, if any */
+		finalize_primnode((Node *) agg->args, context);
+		finalize_primnode((Node *) agg->aggfilter, context);
+		return false;			/* there can't be any Aggrefs below here */
+	}
+	return expression_tree_walker(node, finalize_agg_primnode,
+								  (void *) context);
+}
+
+/*
+ * SS_make_initplan_output_param - make a Param for an initPlan's output
+ *
+ * The plan is expected to return a scalar value of the given type/collation.
+ *
+ * Note that in some cases the initplan may not ever appear in the finished
+ * plan tree.  If that happens, we'll have wasted a PARAM_EXEC slot, which
+ * is no big deal.
+ */
+Param *
+SS_make_initplan_output_param(PlannerInfo *root,
+							  Oid resulttype, int32 resulttypmod,
+							  Oid resultcollation)
+{
+	return generate_new_exec_param(root, resulttype,
+								   resulttypmod, resultcollation);
+}
+
+/*
+ * SS_make_initplan_from_plan - given a plan tree, make it an InitPlan
+ *
+ * We build an EXPR_SUBLINK SubPlan node and put it into the initplan
+ * list for the outer query level.  A Param that represents the initplan's
+ * output has already been assigned using SS_make_initplan_output_param.
+ */
+void
+SS_make_initplan_from_plan(PlannerInfo *root,
+						   PlannerInfo *subroot, Plan *plan,
+						   Param *prm)
+{
+	SubPlan    *node;
+
+	/*
+	 * Add the subplan and its PlannerInfo to the global lists.
+	 */
+	root->glob->subplans = lappend(root->glob->subplans, plan);
+	root->glob->subroots = lappend(root->glob->subroots, subroot);
+
+	/*
+	 * Create a SubPlan node and add it to the outer list of InitPlans. Note
+	 * it has to appear after any other InitPlans it might depend on (see
+	 * comments in ExecReScan).
+	 */
+	node = makeNode(SubPlan);
+	node->subLinkType = EXPR_SUBLINK;
+	node->plan_id = list_length(root->glob->subplans);
+	node->plan_name = psprintf("InitPlan %d (returns $%d)",
+							   node->plan_id, prm->paramid);
+	get_first_col_type(plan, &node->firstColType, &node->firstColTypmod,
+					   &node->firstColCollation);
+	node->setParam = list_make1_int(prm->paramid);
+
+	root->init_plans = lappend(root->init_plans, node);
+
+	/*
+	 * The node can't have any inputs (since it's an initplan), so the
+	 * parParam and args lists remain empty.
+	 */
+
+	/* Set costs of SubPlan using info from the plan tree */
+	cost_subplan(subroot, node, plan);
+}