/*
 * Tencent is pleased to support the open source community by making TBase available.  
 * 
 * Copyright (C) 2019 THL A29 Limited, a Tencent company.  All rights reserved.
 * 
 * TBase is licensed under the BSD 3-Clause License, except for the third-party component listed below. 
 * 
 * A copy of the BSD 3-Clause License is included in this file.
 * 
 * Other dependencies and licenses:
 * 
 * Open Source Software Licensed Under the PostgreSQL License: 
 * --------------------------------------------------------------------
 * 1. Postgres-XL XL9_5_STABLE
 * Portions Copyright (c) 2015-2016, 2ndQuadrant Ltd
 * Portions Copyright (c) 2012-2015, TransLattice, Inc.
 * Portions Copyright (c) 2010-2017, Postgres-XC Development Group
 * Portions Copyright (c) 1996-2015, The PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, The Regents of the University of California
 * 
 * Terms of the PostgreSQL License: 
 * --------------------------------------------------------------------
 * Permission to use, copy, modify, and distribute this software and its
 * documentation for any purpose, without fee, and without a written agreement
 * is hereby granted, provided that the above copyright notice and this
 * paragraph and the following two paragraphs appear in all copies.
 * 
 * IN NO EVENT SHALL THE UNIVERSITY OF CALIFORNIA BE LIABLE TO ANY PARTY FOR
 * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, INCLUDING
 * LOST PROFITS, ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS
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 * THE UNIVERSITY OF CALIFORNIA SPECIFICALLY DISCLAIMS ANY WARRANTIES,
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
 * AND FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
 * ON AN "AS IS" BASIS, AND THE UNIVERSITY OF CALIFORNIA HAS NO OBLIGATIONS TO
 * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
 * 
 * 
 * Terms of the BSD 3-Clause License:
 * --------------------------------------------------------------------
 * Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:
 * 
 * 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
 * 
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 * and/or other materials provided with the distribution.
 * 
 * 3. Neither the name of THL A29 Limited nor the names of its contributors may be used to endorse or promote products derived from this software without 
 * specific prior written permission.
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 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, 
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 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE 
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 */
/*-------------------------------------------------------------------------
 *
 * subselect.c
 *      Planning routines for subselects and parameters.
 *
 * Portions Copyright (c) 2012-2014, TransLattice, Inc.
 * Portions Copyright (c) 1996-2017, 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/pathnode.h"
#include "optimizer/planmain.h"
#include "optimizer/planner.h"
#include "optimizer/prep.h"
#include "optimizer/subselect.h"
#include "optimizer/var.h"
#include "parser/parse_relation.h"
#include "rewrite/rewriteManip.h"
#include "utils/builtins.h"
#include "utils/lsyscache.h"
#include "utils/syscache.h"
#ifdef PGXC
#include "pgxc/pgxc.h"
#endif
#ifdef __TBASE__
#include <math.h>
#include "nodes/pg_list.h"
#include "parser/parse_oper.h"
#include "parser/parse_func.h"
#include "catalog/pg_aggregate.h"
#endif

#ifdef __TBASE__
bool  enable_pullup_subquery = false;
#endif

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;
	int			refcount;		/* number of remaining references */
	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, bool adjust_testexpr,
              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 testexpr_is_hashable(Node *testexpr);
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,
              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);

#ifdef __TBASE__
static Expr * convert_OR_EXIST_sublink_to_join(PlannerInfo *root,
			  SubLink *sublink, Node **jtlink);
static Node * get_or_exist_subquery_targetlist(PlannerInfo *root, Node *node,
			  List **targetList, List **joinClause, int *next_attno);
static bool is_simple_subquery(Query *subquery, JoinExpr *lowest_outer_join,
			  bool deletion_ok);
#endif
/*
 * Select a PARAM_EXEC number to identify the given Var as a parameter for
 * the current subquery, or for a nestloop's inner scan.
 * If the Var already has a param in the current context, return that one.
 */
static int
assign_param_for_var(PlannerInfo *root, Var *var)
{// #lizard forgives
    ListCell   *ppl;
    PlannerParamItem *pitem;
    Index        levelsup;

    /* Find the query level the Var belongs to */
    for (levelsup = var->varlevelsup; levelsup > 0; levelsup--)
        root = root->parent_root;

    /* If there's already a matching PlannerParamItem there, just use it */
    foreach(ppl, root->plan_params)
    {
        pitem = (PlannerParamItem *) lfirst(ppl);
        if (IsA(pitem->item, Var))
        {
            Var           *pvar = (Var *) pitem->item;

            /*
             * This comparison must match _equalVar(), except for ignoring
             * varlevelsup.  Note that _equalVar() ignores the location.
             */
            if (pvar->varno == var->varno &&
                pvar->varattno == var->varattno &&
                pvar->vartype == var->vartype &&
                pvar->vartypmod == var->vartypmod &&
                pvar->varcollid == var->varcollid &&
                pvar->varnoold == var->varnoold &&
                pvar->varoattno == var->varoattno)
                return pitem->paramId;
        }
    }

    /* Nope, so make a new one */
    var = copyObject(var);
    var->varlevelsup = 0;

    pitem = makeNode(PlannerParamItem);
    pitem->item = (Node *) var;
    pitem->paramId = root->glob->nParamExec++;

    root->plan_params = lappend(root->plan_params, pitem);

    return pitem->paramId;
}

/*
 * Generate a Param node to replace the given Var,
 * which is expected to have varlevelsup > 0 (ie, it is not local).
 */
static Param *
replace_outer_var(PlannerInfo *root, Var *var)
{
    Param       *retval;
    int            i;

    Assert(var->varlevelsup > 0 && var->varlevelsup < root->query_level);

    /* Find the Var in the appropriate plan_params, or add it if not present */
    i = assign_param_for_var(root, var);

    retval = makeNode(Param);
    retval->paramkind = PARAM_EXEC;
    retval->paramid = i;
    retval->paramtype = var->vartype;
    retval->paramtypmod = var->vartypmod;
    retval->paramcollid = var->varcollid;
    retval->location = var->location;

    return retval;
}

/*
 * Generate a Param node to replace the given Var, which will be supplied
 * from an upper NestLoop join node.
 *
 * This is effectively the same as replace_outer_var, except that we expect
 * the Var to be local to the current query level.
 */
Param *
assign_nestloop_param_var(PlannerInfo *root, Var *var)
{
    Param       *retval;
    int            i;

    Assert(var->varlevelsup == 0);

    i = assign_param_for_var(root, var);

    retval = makeNode(Param);
    retval->paramkind = PARAM_EXEC;
    retval->paramid = i;
    retval->paramtype = var->vartype;
    retval->paramtypmod = var->vartypmod;
    retval->paramcollid = var->varcollid;
    retval->location = var->location;

    return retval;
}

/*
 * Select a PARAM_EXEC number to identify the given PlaceHolderVar as a
 * parameter for the current subquery, or for a nestloop's inner scan.
 * If the PHV already has a param in the current context, return that one.
 *
 * This is just like assign_param_for_var, except for PlaceHolderVars.
 */
static int
assign_param_for_placeholdervar(PlannerInfo *root, PlaceHolderVar *phv)
{
    ListCell   *ppl;
    PlannerParamItem *pitem;
    Index        levelsup;

    /* Find the query level the PHV belongs to */
    for (levelsup = phv->phlevelsup; levelsup > 0; levelsup--)
        root = root->parent_root;

    /* If there's already a matching PlannerParamItem there, just use it */
    foreach(ppl, root->plan_params)
    {
        pitem = (PlannerParamItem *) lfirst(ppl);
        if (IsA(pitem->item, PlaceHolderVar))
        {
            PlaceHolderVar *pphv = (PlaceHolderVar *) pitem->item;

            /* We assume comparing the PHIDs is sufficient */
            if (pphv->phid == phv->phid)
                return pitem->paramId;
        }
    }

    /* Nope, so make a new one */
    phv = copyObject(phv);
    if (phv->phlevelsup != 0)
    {
        IncrementVarSublevelsUp((Node *) phv, -((int) phv->phlevelsup), 0);
        Assert(phv->phlevelsup == 0);
    }

    pitem = makeNode(PlannerParamItem);
    pitem->item = (Node *) phv;
    pitem->paramId = root->glob->nParamExec++;

    root->plan_params = lappend(root->plan_params, pitem);

    return pitem->paramId;
}

/*
 * Generate a Param node to replace the given PlaceHolderVar,
 * which is expected to have phlevelsup > 0 (ie, it is not local).
 *
 * This is just like replace_outer_var, except for PlaceHolderVars.
 */
static Param *
replace_outer_placeholdervar(PlannerInfo *root, PlaceHolderVar *phv)
{
    Param       *retval;
    int            i;

    Assert(phv->phlevelsup > 0 && phv->phlevelsup < root->query_level);

    /* Find the PHV in the appropriate plan_params, or add it if not present */
    i = assign_param_for_placeholdervar(root, phv);

    retval = makeNode(Param);
    retval->paramkind = PARAM_EXEC;
    retval->paramid = i;
    retval->paramtype = exprType((Node *) phv->phexpr);
    retval->paramtypmod = exprTypmod((Node *) phv->phexpr);
    retval->paramcollid = exprCollation((Node *) phv->phexpr);
    retval->location = -1;

    return retval;
}

/*
 * Generate a Param node to replace the given PlaceHolderVar, which will be
 * supplied from an upper NestLoop join node.
 *
 * This is just like assign_nestloop_param_var, except for PlaceHolderVars.
 */
Param *
assign_nestloop_param_placeholdervar(PlannerInfo *root, PlaceHolderVar *phv)
{
    Param       *retval;
    int            i;

    Assert(phv->phlevelsup == 0);

    i = assign_param_for_placeholdervar(root, phv);

    retval = makeNode(Param);
    retval->paramkind = PARAM_EXEC;
    retval->paramid = i;
    retval->paramtype = exprType((Node *) phv->phexpr);
    retval->paramtypmod = exprTypmod((Node *) phv->phexpr);
    retval->paramcollid = exprCollation((Node *) phv->phexpr);
    retval->location = -1;

    return retval;
}

/*
 * Generate a Param node to replace the given Aggref
 * which is expected to have agglevelsup > 0 (ie, it is not local).
 */
static Param *
replace_outer_agg(PlannerInfo *root, Aggref *agg)
{
    Param       *retval;
    PlannerParamItem *pitem;
    Index        levelsup;

    Assert(agg->agglevelsup > 0 && agg->agglevelsup < root->query_level);

    /* Find the query level the Aggref belongs to */
    for (levelsup = agg->agglevelsup; levelsup > 0; levelsup--)
        root = root->parent_root;

    /*
     * It does not seem worthwhile to try to match duplicate outer aggs. Just
     * make a new slot every time.
     */
    agg = copyObject(agg);
    IncrementVarSublevelsUp((Node *) agg, -((int) agg->agglevelsup), 0);
    Assert(agg->agglevelsup == 0);

    pitem = makeNode(PlannerParamItem);
    pitem->item = (Node *) agg;
    pitem->paramId = root->glob->nParamExec++;

    root->plan_params = lappend(root->plan_params, pitem);

    retval = makeNode(Param);
    retval->paramkind = PARAM_EXEC;
    retval->paramid = pitem->paramId;
    retval->paramtype = agg->aggtype;
    retval->paramtypmod = -1;
    retval->paramcollid = agg->aggcollid;
    retval->location = agg->location;

    return retval;
}

/*
 * Generate a Param node to replace the given GroupingFunc expression which is
 * expected to have agglevelsup > 0 (ie, it is not local).
 */
static Param *
replace_outer_grouping(PlannerInfo *root, GroupingFunc *grp)
{
    Param       *retval;
    PlannerParamItem *pitem;
    Index        levelsup;

    Assert(grp->agglevelsup > 0 && grp->agglevelsup < root->query_level);

    /* Find the query level the GroupingFunc belongs to */
    for (levelsup = grp->agglevelsup; levelsup > 0; levelsup--)
        root = root->parent_root;

    /*
     * It does not seem worthwhile to try to match duplicate outer aggs. Just
     * make a new slot every time.
     */
    grp = copyObject(grp);
    IncrementVarSublevelsUp((Node *) grp, -((int) grp->agglevelsup), 0);
    Assert(grp->agglevelsup == 0);

    pitem = makeNode(PlannerParamItem);
    pitem->item = (Node *) grp;
    pitem->paramId = root->glob->nParamExec++;

    root->plan_params = lappend(root->plan_params, pitem);

    retval = makeNode(Param);
    retval->paramkind = PARAM_EXEC;
    retval->paramid = pitem->paramId;
    retval->paramtype = exprType((Node *) grp);
    retval->paramtypmod = -1;
    retval->paramcollid = InvalidOid;
    retval->location = grp->location;

    return retval;
}

/*
 * Generate a new Param node that will not conflict with any other.
 *
 * This is used to create Params representing subplan outputs.
 * We don't need to build a PlannerParamItem for such a Param, but we do
 * need to record the PARAM_EXEC slot number as being allocated.
 */
static Param *
generate_new_param(PlannerInfo *root, Oid paramtype, int32 paramtypmod,
                   Oid paramcollation)
{
    Param       *retval;

    retval = makeNode(Param);
    retval->paramkind = PARAM_EXEC;
    retval->paramid = root->glob->nParamExec++;
    retval->paramtype = paramtype;
    retval->paramtypmod = paramtypmod;
    retval->paramcollid = paramcollation;
    retval->location = -1;

    return retval;
}

/*
 * Assign a (nonnegative) PARAM_EXEC ID for a special parameter (one that
 * is not actually used to carry a value at runtime).  Such parameters are
 * used for special runtime signaling purposes, such as connecting a
 * recursive union node to its worktable scan node or forcing plan
 * re-evaluation within the EvalPlanQual mechanism.  No actual Param node
 * exists with this ID, however.
 */
int
SS_assign_special_param(PlannerInfo *root)
{
    return root->glob->nParamExec++;
}

/*
 * 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;
}

#ifdef __TBASE__
/*
 * Check if there is a range table entry of type func expr whose arguments
 * are correlated
 */
bool
has_correlation_in_funcexpr_rte(List *rtable)
{
	/*
	 * check if correlation occurs in a func expr in the from clause of the
	 * subselect
	 */
	ListCell   *lc_rte;

	foreach(lc_rte, rtable)
	{
		RangeTblEntry *rte = (RangeTblEntry *) lfirst(lc_rte);

		if (rte->functions && contain_vars_upper_level((Node *) rte->functions, 1))
		{
			return true;
		}
	}
	return false;
}

/*
 * is_simple_subquery
 *	  Check a subquery in the range table to see if it's simple enough
 *	  to pull up into the parent query.
 *
 * rte is the RTE_SUBQUERY RangeTblEntry that contained the subquery.
 * (Note subquery is not necessarily equal to rte->subquery; it could be a
 * processed copy of that.)
 * lowest_outer_join is the lowest outer join above the subquery, or NULL.
 * deletion_ok is TRUE if it'd be okay to delete the subquery entirely.
 */
static bool
is_simple_subquery(Query *subquery,
				   JoinExpr *lowest_outer_join,
				   bool deletion_ok)
{
	/*
	 * Let's just make sure it's a valid subselect ...
	 */
	if (!IsA(subquery, Query) ||
		subquery->commandType != CMD_SELECT)
		elog(ERROR, "subquery is bogus");

	/*
	 * Can't currently pull up a query with setops (unless it's simple UNION
	 * ALL, which is handled by a different code path). Maybe after querytree
	 * redesign...
	 */
	if (subquery->setOperations)
		return false;

	/*
	 * Can't pull up a subquery involving grouping, aggregation, SRFs,
	 * sorting, limiting, or WITH.  (XXX WITH could possibly be allowed later)
	 *
	 * We also don't pull up a subquery that has explicit FOR UPDATE/SHARE
	 * clauses, because pullup would cause the locking to occur semantically
	 * higher than it should.  Implicit FOR UPDATE/SHARE is okay because in
	 * that case the locking was originally declared in the upper query
	 * anyway.
	 */
	if (subquery->hasAggs ||
		subquery->hasWindowFuncs ||
		subquery->hasTargetSRFs ||
		subquery->groupClause ||
		subquery->groupingSets ||
		subquery->havingQual ||
		subquery->sortClause ||
		subquery->distinctClause ||
		subquery->limitOffset ||
		subquery->limitCount ||
		subquery->hasForUpdate ||
		subquery->cteList)
		return false;

	/*
	 * Don't pull up a subquery with an empty jointree, unless it has no quals
	 * and deletion_ok is TRUE and we're not underneath an outer join.
	 *
	 * query_planner() will correctly generate a Result plan for a jointree
	 * that's totally empty, but we can't cope with an empty FromExpr
	 * appearing lower down in a jointree: we identify join rels via baserelid
	 * sets, so we couldn't distinguish a join containing such a FromExpr from
	 * one without it.  We can only handle such cases if the place where the
	 * subquery is linked is a FromExpr or inner JOIN that would still be
	 * nonempty after removal of the subquery, so that it's still identifiable
	 * via its contained baserelids.  Safe contexts are signaled by
	 * deletion_ok.
	 *
	 * But even in a safe context, we must keep the subquery if it has any
	 * quals, because it's unclear where to put them in the upper query.
	 *
	 * Also, we must forbid pullup if such a subquery is underneath an outer
	 * join, because then we might need to wrap its output columns with
	 * PlaceHolderVars, and the PHVs would then have empty relid sets meaning
	 * we couldn't tell where to evaluate them.  (This test is separate from
	 * the deletion_ok flag for possible future expansion: deletion_ok tells
	 * whether the immediate parent site in the jointree could cope, not
	 * whether we'd have PHV issues.  It's possible this restriction could be
	 * fixed by letting the PHVs use the relids of the parent jointree item,
	 * but that complication is for another day.)
	 *
	 * Note that deletion of a subquery is also dependent on the check below
	 * that its targetlist contains no set-returning functions.  Deletion from
	 * a FROM list or inner JOIN is okay only if the subquery must return
	 * exactly one row.
	 */
	if (subquery->jointree->fromlist == NIL &&
		(subquery->jointree->quals != NULL ||
		 !deletion_ok ||
		 lowest_outer_join != NULL))
		return false;

	/*
	 * Don't pull up a subquery that has any volatile functions in its
	 * targetlist.  Otherwise we might introduce multiple evaluations of these
	 * functions, if they get copied to multiple places in the upper query,
	 * leading to surprising results.  (Note: the PlaceHolderVar mechanism
	 * doesn't quite guarantee single evaluation; else we could pull up anyway
	 * and just wrap such items in PlaceHolderVars ...)
	 */
	if (contain_volatile_functions((Node *) subquery->targetList))
		return false;

	return true;
}
#endif

/*
 * 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)
{// #lizard forgives
    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 work_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);

    if (!subroot->distribution)
        subroot->distribution = best_path->distribution;

    plan = create_plan(subroot, best_path);

#ifdef XCP
    /* Add a custom remote subplan if a re-distribution is needed. */
    if (subroot->distribution)
    {
        remote_subplan_depth++;
        plan = (Plan *) make_remotesubplan(subroot,
                                           plan,
                                           NULL,
                                           subroot->distribution,
                                           subroot->query_pathkeys);
        remote_subplan_depth--;
        /*
         * SS_finalize_plan has already been run on the subplan,
         * so we have to copy parameter info to wrapper plan node.
         */
        plan->extParam = bms_copy(plan->lefttree->extParam);
        plan->allParam = bms_copy(plan->lefttree->allParam);
    }
#endif

    /* And convert to SubPlan or InitPlan format. */
    result = build_subplan(root, plan, subroot, plan_params,
                           subLinkType, subLinkId,
                           testexpr, true, isTopQual);
#ifdef PGXC
    /* This is not necessary for a PGXC Coordinator, we just need one plan */
    if (IS_PGXC_LOCAL_COORDINATOR)
        return result;
#endif

    /*
     * 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 the executor 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 and turn it into a Plan */
            final_rel = fetch_upper_rel(subroot, UPPERREL_FINAL, NULL);
            best_path = final_rel->cheapest_total_path;

            plan = create_plan(subroot, best_path);

            /* Now we can check if it'll fit in work_mem */
            /* XXX can we check this at the Path stage? */
            if (subplan_is_hashable(plan))
            {
                SubPlan    *hashplan;
                AlternativeSubPlan *asplan;

                /* OK, convert to SubPlan format. */
                hashplan = castNode(SubPlan,
                                    build_subplan(root, plan, subroot,
                                                  plan_params,
                                                  ANY_SUBLINK, 0,
                                                  newtestexpr,
                                                  false, true));
                /* Check we got what we expected */
                Assert(hashplan->parParam == NIL);
                Assert(hashplan->useHashTable);
                /* build_subplan won't have filled in paramIds */
                hashplan->paramIds = paramIds;

                /* Leave it to the executor to decide which plan to use */
                asplan = makeNode(AlternativeSubPlan);
                asplan->subplans = list_make2(result, hashplan);
                result = (Node *) asplan;
            }
        }
    }

    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, bool adjust_testexpr,
              bool unknownEqFalse)
{// #lizard forgives
    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, or Aggref has already been adjusted to
         * have the correct varlevelsup, phlevelsup, or agglevelsup.
         *
         * If it's a PlaceHolderVar or Aggref, 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))
            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_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_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_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 said it's not
         * needed.
         */
        if (testexpr && adjust_testexpr)
        {
            List       *params;

            params = generate_subquery_params(root,
                                              plan->targetlist,
                                              &splan->paramIds);
            splan->testexpr = convert_testexpr(root,
                                               testexpr,
                                               params);
        }
        else
            splan->testexpr = testexpr;

        /*
         * 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->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(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_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?
 */
static bool
subplan_is_hashable(Plan *plan)
{
    double        subquery_size;

    /*
     * The estimated size of the subquery result must fit in work_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 > work_mem * 1024L)
        return false;

    return true;
}

/*
 * testexpr_is_hashable: is an ANY SubLink's test expression hashable?
 */
static bool
testexpr_is_hashable(Node *testexpr)
{
    /*
     * The testexpr must be a single OpExpr, or an AND-clause containing only
     * OpExprs.
     *
     * The combining operators 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: they can't yield
     * NULL for non-null inputs, either (see nodeSubplan.c).  However, hash
     * indexes and hash joins assume that too.
     */
    if (testexpr && IsA(testexpr, OpExpr))
    {
        if (hash_ok_operator((OpExpr *) testexpr))
            return true;
    }
    else if (and_clause(testexpr))
    {
        ListCell   *l;

        foreach(l, ((BoolExpr *) testexpr)->args)
        {
            Node       *andarg = (Node *) lfirst(l);

            if (!IsA(andarg, OpExpr))
                return false;
            if (!hash_ok_operator((OpExpr *) andarg))
                return false;
        }
        return true;
    }

    return false;
}

/*
 * 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)
    {
        /* array_eq is strict, but must check input type to ensure hashable */
        /* XXX record_eq will need same treatment when it becomes 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;
    }
}

#ifdef __TBASE__
/*
 * Check if total cost of inlining to multiple subquery is cheaper.
 *
 * There are three alternatives to optimize CTE with multiple references.
 * XXX Keep the CTE as an optimization fence, using materialized CTE scan could
 * 	   be cost saving. But in TBase distributed system, this will lead to more
 * 	   executor nodes perfored in CN, which could be much slower.
 * XXX Inline the CTE to multiple subqueries. This could leverage more join
 *     reordering and predicate pushdown opetimization automatically.
 * XXX Inline the CTE to some of the reference place(s). This need an overall
 *     cost based optimizer including CTE inline and sublink pullup phase,
 *     postgres optimizer does not support this yet.
 */
static bool
is_cte_worth_inline(CommonTableExpr *cte, Plan *plan, Path *path)
{
	Cost 	inline_total_cost = 0;
	Cost 	cte_total_cost = 0;
	Cost 	material_cost = 0;
	double 	material_bytes = 0;
	long	work_mem_bytes = work_mem * 1024L;

	/* Force pullup multi-reference CTE when enable_pullup_subquery enabled */
	if (enable_pullup_subquery)
		return true;

	/* Num bytes to be materialized by CTE */
	material_bytes = plan->plan_rows * plan->plan_width;

	/*
	 * Whether spilling or not, charge 2x cpu_operator_cost per tuple to
	 * reflect bookkeeping overhead.  (This rate must be more than what
	 * cost_rescan charges for materialize, ie, cpu_operator_cost per tuple;
	 * if it is exactly the same then there will be a cost tie between
	 * nestloop with A outer, materialized B inner and nestloop with B outer,
	 * materialized A inner.  The extra cost ensures we'll prefer
	 * materializing the smaller rel.)	Note that this is normally a good deal
	 * less than cpu_tuple_cost; which is OK because a Material plan node
	 * doesn't do qual-checking or projection, so it's got less overhead than
	 * most plan nodes.
	 */
	material_cost += 2 * cpu_operator_cost * plan->plan_rows;

	/*
	 * If we will spill to disk, charge at the rate of seq_page_cost per page.
	 * This cost is assumed to be evenly spread through the plan run phase,
	 * which isn't exactly accurate but our cost model doesn't allow for
	 * nonuniform costs within the run phase.
	 */
	if (material_bytes > work_mem_bytes)
	{
		double npages = ceil(material_bytes / BLCKSZ);

		material_bytes += seq_page_cost * npages;
	}

	/* Calculate total costs for different options */
	cte_total_cost = plan->total_cost + material_cost;
	inline_total_cost = plan->total_cost * cte->cterefcount;

	/*
	 * In a distributed system like TBase, the inline one could leverage more
	 * optimizations like subquery pullup, predicate pushdown, etc. We add a
	 * optimization factor 0.5 here to show case these cost saves.
	 */
	inline_total_cost = inline_total_cost * 0.5;

	if (inline_total_cost <= cte_total_cost)
		return true;
	else
		return false;
}
#endif

/*
 * 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;

		if (!subroot->distribution)
			subroot->distribution = best_path->distribution;

		plan = create_plan(subroot, best_path);

#ifdef __TBASE__
		/*
		 * Handle the CTE with multiple references in the main query. Since we
		 * need to compare the cost between CTE Scan and inline subquery Scan,
		 * perform the inline check after we got the best path of CTE subquery.
		 */
		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))
		{
			/*
			 * Check if total cost of inlining to multiple subquery is cheaper.
			 */
			if (is_cte_worth_inline(cte, plan, best_path))
			{
				inline_cte(root, cte);
				/* Make a dummy entry in cte_plan_ids */
				root->cte_plan_ids = lappend_int(root->cte_plan_ids, -1);
				continue;
			}
		}
#endif

#ifdef XCP
        /* Add a remote subplan, if redistribution is needed. */
        if (subroot->distribution)
        {
            remote_subplan_depth++;
            plan = (Plan *) make_remotesubplan(subroot,
                                               plan,
                                               NULL,
                                               subroot->distribution,
                                               subroot->query_pathkeys);
            remote_subplan_depth--;
            /*
             * SS_finalize_plan has already been run on the subplan,
             * so we have to copy parameter info to wrapper plan node.
             */
            plan->extParam = bms_copy(plan->lefttree->extParam);
            plan->allParam = bms_copy(plan->lefttree->allParam);
        }
#endif

        /*
         * 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 = SS_assign_special_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);
    }
}

#ifdef __TBASE__
static bool
simplify_EXPR_query(PlannerInfo *root, Query *query)
{// #lizard forgives
    Node *whereclause = NULL;
    ListCell *lc = NULL;

    if (!enable_pullup_subquery)
        return false;
    
    if (query->commandType != CMD_SELECT ||
        query->setOperations ||
        query->groupClause ||
        query->groupingSets ||
        query->hasWindowFuncs ||
        query->hasTargetSRFs ||
        query->hasModifyingCTE ||
        query->havingQual ||
        query->limitOffset ||
		query->limitCount ||
        query->rowMarks ||
        query->hasSubLinks ||
        query->cteList ||
        query->distinctClause ||
        query->sortClause)
        return false;

    foreach(lc, query->rtable)
    {
    	RangeTblEntry *rte = (RangeTblEntry *)lfirst(lc);
    	if (rte->rtekind == RTE_SUBQUERY)
    	{
    		return false;
    	}
    }

    whereclause = query->jointree->quals;
    
    if (contain_vars_upper_level((Node *)whereclause, 1))
        return false;

    query->jointree->quals = NULL;
    if (contain_vars_upper_level((Node *)query, 0))
    {
        query->jointree->quals = whereclause;
        return false;
    }
    query->jointree->quals = whereclause;

    return true;
}

static bool
simplify_ALL_query(PlannerInfo *root, Query *query)
{
    return false;
}

/* 
 * If where clause contains 'not' BoolExpr or not-equal OpExpr, return true.
 */
static bool
contain_notexpr_or_neopexpr(Node *whereclause, bool check_or, List **joinquals)
{// #lizard forgives
    ListCell *cell;
    
    if (IsA(whereclause, BoolExpr))
    {
        BoolExpr *expr = (BoolExpr *)whereclause;

		if (or_clause(whereclause))
        {
			List *last = NIL;
			int i = 0;

			if(!check_or)
                return true;

			/* Look for common EXPR */
			foreach(cell, expr->args)
			{
				List *cur = NIL;
				
				if(contain_notexpr_or_neopexpr(lfirst(cell), check_or, &cur))
					return true;

				if (i == 0)
				{
					last = cur;
				}
				else if (!equal(last, cur))
				{
					return true;
				}

				i++;
			}

			*joinquals = list_concat(*joinquals, last);

			return false;
        }

		/* AND EXPR */
		foreach(cell, expr->args)
		{
			bool result;
			Node *arg = lfirst(cell);

			result = contain_notexpr_or_neopexpr(arg, check_or, joinquals);

            if (result)
                return true;
        }

        return false;
    }
    else if (IsA(whereclause, OpExpr))
    {
        OpExpr *expr = (OpExpr *)whereclause;
        Expr *lexpr  =  linitial(expr->args);

        if (!contain_vars_of_level((Node *)expr, 1))
            return false;

        if (!contain_vars_of_level((Node *)expr, 0))
            return false;

        *joinquals = lappend(*joinquals, expr);

		/* Make sure the operator is hashjoinable */
		if (!op_hashjoinable(expr->opno, exprType((Node *)lexpr)))
        {
			return true;
		}

		/* Check the operands of the OpExpr */
		foreach(cell, expr->args)
		{
			bool result;
			Node *arg = lfirst(cell);

			result = contain_notexpr_or_neopexpr(arg, check_or, joinquals);

            if (result)
                return true;
        }

        return false;
    }
    else if (IsA(whereclause, Var))
    {
        return false;
    }
    else if (IsA(whereclause, RelabelType))
    {
        bool result;
        RelabelType *label = (RelabelType *)whereclause;

		result = contain_notexpr_or_neopexpr((Node *)label->arg,
											 check_or,
											 joinquals);
		if (result)
				return true;
		return false;
	}
	/* In case the where clause is "tbl.col_a IN ('0','1')" */
	else if (IsA(whereclause, ScalarArrayOpExpr))
	{
		ListCell 		  *lc = NULL;
		ScalarArrayOpExpr *scalarArray = (ScalarArrayOpExpr*)whereclause;
		Expr 			  *lexpr = linitial(scalarArray->args);

		if (!op_hashjoinable(scalarArray->opno, exprType((Node *)lexpr)))
		{
			return true;
		}

		foreach(lc, scalarArray->args)
		{
			if (contain_notexpr_or_neopexpr((Node *)lfirst(lc),
											check_or,
											joinquals))
			{
				return true;
			}
		}

		return false;
	}
	/*
	 * The right operand of ScalarArrayOpExpr, we only support array of
	 * constant values
	 */
	else if (IsA(whereclause, ArrayExpr))
	{
		ListCell *lc = NULL;
		ArrayExpr *arrayExpr = (ArrayExpr *)whereclause;

		foreach(lc, arrayExpr->elements)
		{
			if (!IsA((Node *)lfirst(lc), Const))
			{
				return true;
			}
		}

		return false;
	}
    /* In case the where clause is "tbl.col_a is(is not) NULL" */
	else if (IsA(whereclause, NullTest))
	{
		NullTest *nullTestExpr = (NullTest *)whereclause;

		if (contain_notexpr_or_neopexpr((Node *)nullTestExpr->arg,
										check_or,
										joinquals))
		{
			return true;
		}
		return false;
	}

    return true;
}

static List *
append_var_to_subquery_targetlist(Var *var, List *targetList, TargetEntry **target)
{
	Var *temp_var = NULL;
	TargetEntry *ent = NULL;
	int varno = 0;

	temp_var = copyObject(var);

	ent = makeTargetEntry((Expr *)temp_var, temp_var->varoattno, NULL, false);

	targetList = lappend(targetList, ent);
	varno = list_length(targetList);

	ent->resno = varno;
	var->varattno = var->varoattno = varno;

	if(target != NULL)
        *target = ent;
	return targetList;
}

static void
add_vars_to_subquery_targetlist(Node     *whereClause, Query *subselect, int rtindex, int offset)
{
    ListCell *cell;
    List *vars = pull_vars_of_level((Node *)whereClause, 0);

    foreach(cell, vars)
    {
        Var *var = lfirst(cell);

		if (var->varno == rtindex || rtindex == -1)
        {
            bool match = false;
            ListCell *lc;
            Var *temp_var = NULL;
            TargetEntry *ent = NULL;
            int varno         = 0;
            int varlevelsup  = 0;

            if (var->varlevelsup >= 1)
            {
                varlevelsup = var->varlevelsup;
                var->varlevelsup = 0;
            }
            
            temp_var = copyObject(var);
            temp_var->varno -= offset;
            temp_var->varnoold -= offset;

            match = false;
            foreach(lc, subselect->targetList)
            {
                TargetEntry *tent = (TargetEntry *) lfirst(lc);

                if (IsA(tent->expr, Var))
                {
                    if (equal(temp_var, tent->expr))
                    {
                        match = true;

                        var->varattno = var->varoattno = tent->resno;
                        
                        break;
                    }
                }
            }

            if (!match)
            {
				ent = makeTargetEntry((Expr *)temp_var, temp_var->varoattno, " ", false);
    
                subselect->targetList = lappend(subselect->targetList, ent);

                varno = list_length(subselect->targetList);

                ent->resno = varno;

                var->varattno = var->varoattno = varno;
            }

            if (varlevelsup)
            {
                var->varlevelsup = varlevelsup;
            }
        }
    }
}

#endif

/*
 * 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.refcount = cte->cterefcount;
	context.ctequery = castNode(Query, cte->ctequery);

	(void) inline_cte_walker((Node *) root->parse, &context);

	/* Assert we replaced all references */
	Assert(context.refcount == 0);
}

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;

			/* Count the number of replacements we've done */
			context->refcount--;
		}

		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.
 */
#ifdef __TBASE__
JoinExpr *
convert_ANY_sublink_to_join(PlannerInfo *root, SubLink *sublink,
                            Relids available_rels, bool under_not)
#else
JoinExpr *
convert_ANY_sublink_to_join(PlannerInfo *root, SubLink *sublink,
                            Relids available_rels)
#endif
{// #lizard forgives
    JoinExpr   *result;
    Query       *parse = root->parse;
    Query       *subselect = (Query *) sublink->subselect;
    Relids        upper_varnos;
    int            rtindex;
    RangeTblEntry *rte;
    RangeTblRef *rtr;
    List       *subquery_vars;
    Node       *quals;
    ParseState *pstate;
#ifdef __TBASE__
	bool		correlated = false;
#endif

    Assert(sublink->subLinkType == ANY_SUBLINK);

#ifdef __TBASE__
	if (enable_pullup_subquery)
	{
		/*
		 * If there are CTEs, then the transformation does not work. Don't attempt
		 * to pullup.
		 */
		if (parse->cteList)
			return NULL;

		/*
		 * If uncorrelated, and no Var nodes on lhs, the subquery will be executed
		 * only once.  It should become an InitPlan, but make_subplan() doesn't
		 * handle that case, so just flatten it for now.
		 * TODO: Let it become an InitPlan, so its QEs can be recycled.
		 *
		 * We only handle level 1 correlated cases. The sub-select must not refer
		 * to any Vars of the parent query. (Vars of higher levels should be okay,
		 * though.)
		 */
		correlated = contain_vars_of_level((Node *) subselect, 1);

		if (correlated)
		{
			/*
			 * If deeply(>1) correlated, then don't pull it up
			 */
			if (contain_vars_upper_level(sublink->subselect, 1))
				return NULL;

			/*
			 * Under certain conditions, we cannot pull up the subquery as a join.
			 */
			if (!is_simple_subquery(subselect, NULL, false))
				return NULL;

			/*
			 * Do not pull subqueries with correlation in a func expr in the from
			 * clause of the subselect
			 */
			if (has_correlation_in_funcexpr_rte(subselect->rtable))
				return NULL;

			if (contain_subplans(subselect->jointree->quals))
				return NULL;
		}
	}
	else
	{
#endif
	/*
	 * 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;
#ifdef __TBASE__
	}

	/* TODO: Currently we do not pullup under_not */
	if (under_not)
		return NULL;
#endif

    /*
     * 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(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.
	 *
	 * If the subquery is correlated, i.e. it refers to any Vars of the
	 * parent query, mark it as lateral.
	 */
	rte = addRangeTableEntryForSubquery(pstate,
										subselect,
										makeAlias("ANY_subquery", NIL),
#ifdef __TBASE__
										correlated,	/* lateral */
#else
										false,
#endif
										false);
	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);
#ifdef __TBASE__
    result->jointype = under_not ? JOIN_ANTI : JOIN_SEMI;
#else
    result->jointype = JOIN_SEMI;
#endif
    result->isNatural = false;
    result->larg = NULL;        /* caller must fill this in */
    result->rarg = (Node *) rtr;
    result->usingClause = NIL;
    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)
{// #lizard forgives
    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;

    /*
     * The subquery must have a nonempty jointree, else we won't have a join.
     */
    if (subselect->jointree->fromlist == NIL)
        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;

    /*
     * 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(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->quals = whereClause;
    result->alias = NULL;
    result->rtindex = 0;        /* we don't need an RTE for it */

    return result;
}

#ifdef __TBASE__
/*
  * try to convert an expr SubLink to a join
  */
JoinExpr *
convert_EXPR_sublink_to_join(PlannerInfo *root, OpExpr *expr,
		                    Relids available_rels, Node **filter)
{// #lizard forgives
    JoinExpr   *result;
    Query *parse = root->parse;
    SubLink *sublink;
    Query *subselect;
    Node *whereClause;
    Relids clause_varnos;
    ListCell *cell;
    int varno;
    int rtindex;
    ParseState *pstate;
    RangeTblEntry *rte;
    RangeTblRef *rtr;
    List *joinquals = NIL;
    List *pullupquals = NIL;
    List *sublinks = NIL;
    int ressortgroupref = 0;
    TargetEntry *ent = NULL;
    bool count_agg = false;
    bool hasAgg = false;
    ListCell *lc;
    TargetEntry *tent;
    List *vars;

    if (root->parse->commandType != CMD_SELECT)
    {
    	return NULL;
    }

    expr = copyObject(expr);

    find_sublink_walker((Node *)expr, &sublinks);

    /* only one sublink can be handled */
    if (list_length(sublinks) != 1)
    {
        return NULL;
    }

    sublink = linitial(sublinks);

    /* only process agg case */
    if (!((Query *)sublink->subselect)->hasAggs)
    {
        return NULL;
    }

    subselect = (Query *)copyObject(sublink->subselect);

    /* we can just handle simple case now! */
    if (!simplify_EXPR_query(root, subselect))
    {
        return NULL;
    }

    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;

    /* subquery must contain one output */
    if (list_length(subselect->targetList) != 1)
        return NULL;

	/* output must not be count */
	tent = (TargetEntry *)linitial(subselect->targetList);

	vars = pull_var_clause((Node *)tent->expr, PVC_INCLUDE_AGGREGATES |
														 PVC_RECURSE_PLACEHOLDERS |
														 PVC_RECURSE_WINDOWFUNCS);
	foreach (lc, vars)
	{
		Node *n = (Node *)lfirst(lc);

		if (IsA(n, Var))
		{
			return NULL;
		}
		else if (IsA(n, Aggref))
		{
			Aggref *ref = (Aggref *)n;
			char *name = NULL;
			hasAgg = true;

			/* count agg */
			if(ref->aggfnoid == 2147 || ref->aggfnoid == 2803)
			{
				count_agg = true;
				continue;
			}

			name = get_func_name(ref->aggfnoid);
			if(name == NULL)
				return NULL;

			/* strict agg is allowed */
			if(strcmp(name,"max") == 0 ||
				strcmp(name,"min") == 0 ||
				strcmp(name,"stddev") == 0 ||
				strcmp(name,"sum") == 0 ||
				strcmp(name,"avg") == 0 ||
				strcmp(name,"variance") == 0 )
			{
				continue;
			}

			return NULL;
		}
	}

	if (!hasAgg)
	{
		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;

    /* process 'op' and 'bool' expr only */
	if (contain_notexpr_or_neopexpr(whereClause, true, &joinquals))
        return NULL;

	/* should not have others quals contain vars of parent query */
	if (pullupquals)
		return NULL;

    /*
     * We don't risk optimizing if the WHERE clause is volatile, either.
     */
    if (contain_volatile_functions(whereClause))
        return NULL;

    /* get vars of parent query */
    clause_varnos = pull_varnos_of_level(whereClause, 1);
    if (bms_is_empty(clause_varnos))
        return NULL;

    /* whereclause contains vars from different parent query */
    if (bms_num_members(clause_varnos) > 1)
        return NULL;

    if (!bms_is_subset(clause_varnos, available_rels))
        return NULL;

	/* 
     * whereclause can only be 'and' expr and 'op =' expr , this
     * has been checked before.
	 */
	if (!joinquals)
		return NULL;

	vars = pull_vars_of_level((Node *)joinquals, 0);

	/* construct groupby clause */
	foreach (cell, vars)
    {
		Oid sortop;
		Oid eqop;
		bool hashable;
		Oid restype;
		SortGroupClause *grpcl;

		Var *var = (Var *)lfirst(cell);

		RangeTblEntry *tbl = (RangeTblEntry *)list_nth(subselect->rtable, var->varno - 1);

		if (tbl->rtekind != RTE_RELATION && tbl->rtekind != RTE_CTE)
			return NULL;

		restype = exprType((Node *)var);

		grpcl = makeNode(SortGroupClause);

		ressortgroupref++;

		if (tbl->rtekind == RTE_RELATION)
		{
            ent = makeTargetEntry((Expr *)copyObject(var), var->varoattno, get_relid_attribute_name(tbl->relid, var->varoattno), false);
		}
		else
		{
			int plan_id;
			int ndx;
			ListCell *lc;
			Plan *cte_plan;
			TargetEntry *cte_ent = NULL;

			/*
			 * Note: cte_plan_ids can be shorter than cteList, if we are still working
			 * on planning the CTEs (ie, this is a side-reference from another CTE).
			 * So we mustn't use forboth here.
			 */
			ndx = 0;
			foreach (lc, root->parse->cteList)
			{
				CommonTableExpr *cte = (CommonTableExpr *)lfirst(lc);

				if (strcmp(cte->ctename, tbl->ctename) == 0)
					break;
				ndx++;
			}
			if (lc == NULL) /* shouldn't happen */
				elog(ERROR, "could not find CTE \"%s\"", tbl->ctename);
			if (ndx >= list_length(root->cte_plan_ids))
				elog(ERROR, "could not find plan for CTE \"%s\"", tbl->ctename);
			plan_id = list_nth_int(root->cte_plan_ids, ndx);
			cte_plan = (Plan *)lfirst(list_nth_cell(root->glob->subplans, plan_id - 1));
			cte_ent = (TargetEntry *)lfirst(list_nth_cell(cte_plan->targetlist, var->varattno - 1));
			ent = makeTargetEntry((Expr *)copyObject(var), var->varoattno, cte_ent->resname, false);
		}

		ent->ressortgroupref = ressortgroupref;

		subselect->targetList = lappend(subselect->targetList, ent);

		varno = list_length(subselect->targetList);

		ent->resno = varno;

		/* determine the eqop and optional sortop */
		get_sort_group_operators(restype,
								 false, true, false,
								 &sortop, &eqop, NULL,
								 &hashable);

		grpcl->tleSortGroupRef = ressortgroupref;
		grpcl->eqop = eqop;
		grpcl->sortop = sortop;
		grpcl->nulls_first = false; /* OK with or without sortop */
		grpcl->hashable = hashable;

		subselect->groupClause = lappend(subselect->groupClause, grpcl);
	}

	rtindex = list_length(parse->rtable);

	add_vars_to_subquery_targetlist((Node *)whereClause, subselect, -1, 0);

	pstate = make_parsestate(NULL);
	rte = addRangeTableEntryForSubquery(pstate,
										subselect,
										makeAlias("EXPR_subquery", NIL),
										false,
										false);
	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;

	/* adjust all sublevelup 0 varno to rtindex */
	{
		int i = 0;
		int n = list_length(subselect->rtable);

		for(i = 1; i <= n ;i++)
			ChangeVarNodes((Node *)whereClause, i, rtindex, 0);
	}

	/* pullup whereclause , all sublevel-1 vars change to 0 */
	IncrementVarSublevelsUp((Node *)whereClause, -1, 1);

	/* form join quals */
	ent = (TargetEntry *)linitial(subselect->targetList);

	{
		Node *target = (Node *)makeVarFromTargetEntry(rtindex, ent);
		
		if(count_agg)
		{
			CoalesceExpr *coalesce = makeNode(CoalesceExpr);
			coalesce->args = list_make2(target,makeConst(INT8OID, -1,InvalidOid,sizeof(int64),Int64GetDatum(0),false,true));
			coalesce->coalescetype = INT8OID;
			target = (Node *)coalesce;
		}
        
		expr = (OpExpr *)substitute_sublink_with_node((Node *)expr, sublink,target);
	}
	/*
	 * And finally, build the JoinExpr node.
	 */
	result = makeNode(JoinExpr);
	result->jointype = JOIN_LEFT;
	result->isNatural = false;
	result->larg = NULL; /* caller must fill this in */
	result->rarg = (Node *)rtr;
	result->usingClause = NIL;
	result->quals = whereClause;
	result->alias = NULL;
	result->rtindex = 0; /* we don't need an RTE for it */


	*filter = (Node *)expr;

	return result;
}

List *
convert_OR_EXIST_sublink_to_join_recurse(PlannerInfo *root, Node *node, Node **jtlink)
{
	List *new_clauses = NIL;
	if (node == NULL)
		return NULL;

	if (IsA(node, SubLink))
	{
		SubLink *sublink = (SubLink *)node;
		Expr *expr = NULL;
		Assert(sublink->subLinkType == EXISTS_SUBLINK);

		expr = convert_OR_EXIST_sublink_to_join(root, sublink, jtlink);
		new_clauses = lappend(new_clauses, expr);
    }
	else if (or_clause(node))
	{
		List *result = NIL;
		ListCell *l;
		foreach (l, ((BoolExpr *)node)->args)
		{
			result = convert_OR_EXIST_sublink_to_join_recurse(root,
															  (Node *)lfirst(l),
															  jtlink);
			if (result)
				new_clauses = list_concat(new_clauses, result);
		}
	}
	return new_clauses;
}

static Node *
get_or_exist_subquery_targetlist(PlannerInfo *root, Node *node, List **targetList, List **joinClause, int *next_attno)
{
	if (and_clause(node))
	{
		ListCell *l = NULL;
		List *new_args = NULL;
		Node *result = NULL;

		foreach (l, ((BoolExpr *)node)->args)
		{
			result = get_or_exist_subquery_targetlist(root, (Node *)lfirst(l), targetList, joinClause, next_attno);
			if (result != NULL)
			{
				new_args = lappend(new_args, result);
			}
		}
		if (list_length(new_args) == 1)
		{
			return (Node *)list_head(new_args);
		}
		else if (list_length(new_args) == 0)
		{
			return NULL;
		}
		return (Node *)make_andclause(new_args);
	}
	else if (IsA(node, OpExpr) && pull_vars_of_level(node, 1) != NULL)
    {
		Node *expr;
		List *vars;
		Var *var;

		vars = pull_vars_of_level(node, 0);

		Assert(list_length(vars) == 1);
        
		*targetList = lappend(*targetList, lfirst(vars->head));
		expr = copyObject(node);
		vars = pull_vars_of_level(expr, 0);
		var  = lfirst(vars->head);

		var->varattno = *next_attno;
		*next_attno = *next_attno + 1;
		*joinClause = lappend(*joinClause, expr);

		return NULL;
	}
	return node;
}

#ifdef __TBASE__
/*
 * simplify_TargetList_query:remove any useless stuff in an TargetList's
 * subquery
 *
 * For subquery in targetlist, normally we use JOIN_LEFT_SCALAR type to
 * make sure there will be only one row found. If subquery contains
 * aggregation clause, then we are OK with JOIN_LEFT_SEMI. Further more, if
 * subquery got 'limit 1' or  equivalent clauses such as Oracle 'rownum = 1'.
 * Then we can remove the limit clause and use JOIN_SEMI to simplify the
 * subquery.
 *
 * Returns TRUE if was able to discard the 'LIMIT 1' cluase or the subquery
 * already simple enough, else FALSE.
 */
static bool
simplify_TargetList_query(PlannerInfo *root, Query *query, bool *useLeftSemiJoin)
{
	/*
	 * 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->groupingSets ||
		query->hasWindowFuncs ||
		query->hasTargetSRFs ||
		query->hasModifyingCTE ||
		query->havingQual ||
		query->limitOffset ||
		query->rowMarks)
		return false;

	/* By default, use JOIN_LEFT_SCALAR. */
	Assert(useLeftSemiJoin);
	*useLeftSemiJoin = false;

	/* Handle 'limit 1' case as described above. */
	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;
		int64		limitValue;

		/* 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);
		limitValue = DatumGetInt64(limit->constvalue);

		/* Invalid value, we have to get at least one row. */
		if (!limit->constisnull && limitValue <= 0)
			return false;

		/*
		 * If the SubQuery got limit 1(actually must be limit 1), then the
		 * join Semantic equals JOIN_SEMI. We don't need to continue when got
		 * one LHS match.
		 */
		if (limitValue == 1)
		{
			/*
			 * Remove the limit clause for more possible subquery pullup
			 * optimizations.
			 */
			query->limitCount = NULL;
			/* Inform caller to use JOIN_LEFT_SEMI */
			*useLeftSemiJoin = true;
		}
	}

	return true;
}

/*
 * Try to convert an SubLink in targetlist to a join
 *
 * The sublink in targetlist has the semantic of SCALAR. Normal joins will join
 * simply generate repeated tuples. So we add a new join type JOIN_LEFT_SCALAR
 * which acts like left join and reports error when scalar semantics is broken.
 *
 * On success, it converts sublink to subquery to parent jointree and returns
 * the converted new targetlist entry. Otherwise, it returnes NULL.
 */
TargetEntry *
convert_TargetList_sublink_to_join(PlannerInfo *root, TargetEntry *entry)
{
	Query		*parse = root->parse;
	Node		*whereClause = NULL;
	Query		*subselect = NULL;
	JoinExpr	*joinExpr = NULL;
	ParseState	*pstate = NULL;
	SubLink		*sublink = NULL;
	RangeTblRef	*rtr = NULL;
	RangeTblEntry *rte = NULL;
	Node		*target = NULL;
	List		*sublinks = NIL;
    bool		 count_agg = false;
    bool		 useLeftSemiJoin = false;
    /* By default, JOIN_LEFT_SCALAR is the worst choice */
    JoinType 	 finalJoinType = JOIN_LEFT_SCALAR;

	/* Find sublinks in the targetlist entry */
	find_sublink_walker((Node *)entry->expr, &sublinks);

	/* Only one sublink can be handled */
	if (list_length(sublinks) != 1)
		return NULL;

	sublink = linitial(sublinks);

	if (sublink->subLinkType != EXPR_SUBLINK)
		return NULL;

	/*
	 * Copy object so that we can modify it.
	 */
	subselect = copyObject((Query *) sublink->subselect);
	whereClause = subselect->jointree->quals;

	/*
	 * Only one targetEntry can be handled.
	 */
	if (list_length(subselect->targetList) > 1)
		return NULL;

	/*
	 * The SubQuery must have a non-empty JoinTree, else we won't have a join.
	 */
	if (subselect->jointree->fromlist == NIL)
		return NULL;

	/*
	 * See if the subquery can be simplified. For now, we just try to remove
	 * 'limit 1' clause. If it's been removed, we can use JOIN_LEFT_SEMI to
	 * save more costs.
	 */
	if (!simplify_TargetList_query(root, subselect, &useLeftSemiJoin))
		return NULL;

	/* 'limit 1' optimized */
	if (useLeftSemiJoin)
		finalJoinType = JOIN_LEFT_SEMI;

	/*
	 * What we can not optimize.
	 */
	if (subselect->commandType != CMD_SELECT || subselect->hasDistinctOn ||
		subselect->setOperations || subselect->groupingSets ||
		subselect->groupClause || subselect->hasWindowFuncs ||
		subselect->hasTargetSRFs || subselect->hasModifyingCTE ||
		subselect->havingQual || subselect->limitOffset ||
		subselect->limitCount || subselect->rowMarks ||
		subselect->cteList || subselect->sortClause)
	{
		return NULL;
	}

	/*
	 * On one 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 rest of the sub-select must not refer to any Vars of the parent
	 * query. (Vars of higher levels should be okay, though.)
	 */
	subselect->jointree->quals = NULL;
	if (contain_vars_of_level((Node *) subselect, 1))
		return NULL;
	subselect->jointree->quals = whereClause;

	if (subselect->hasAggs)
	{
        int ressortgroupref = 0;
        int varno = 0;
		List *joinquals  = NULL;
		List *vars       = NULL;
		TargetEntry *ent = NULL;
		ListCell *cell   = NULL;
		char  *name = NULL;
		Aggref *agg = NULL;
		Node  *expr = linitial(subselect->targetList);

		/* process 'op' and 'bool' expr only */
		if (contain_notexpr_or_neopexpr(whereClause, true, &joinquals))
			return NULL;

		expr = (Node *)((TargetEntry *)expr)->expr;
		/*
		 * First node must be Agg.
		 * we optimize subquery only like "SELECT agg()",
		 * others will not be optimized for now.
		 */
        if (!IsA(expr, Aggref))
            return NULL;

        agg = (Aggref *)expr;
        name = get_func_name(agg->aggfnoid);
        if(!name)
        {
            return NULL;
        }

        /* count agg */
        if (pg_strcasecmp(name, "count") == 0)
        {
            count_agg = true;
        }
        /* strict aggs are allowed */
        else if (pg_strcasecmp(name, "max") != 0    && pg_strcasecmp(name, "min") != 0 &&
                 pg_strcasecmp(name, "stddev") != 0 && pg_strcasecmp(name, "sum") != 0 &&
                 pg_strcasecmp(name, "avg") != 0    && pg_strcasecmp(name, "variance") != 0)
        {
            return NULL;
        }

		vars = pull_vars_of_level((Node *) joinquals, 0);

		/* construct groupby clause */
        foreach (cell, vars)
        {
        	Oid sortop;
        	Oid eqop;
        	bool hashable;
        	Oid restype;
        	SortGroupClause *grpcl;
        	Var *var = (Var *) lfirst(cell);
        	RangeTblEntry *tbl = (RangeTblEntry *) list_nth(subselect->rtable, var->varno - 1);

        	if (tbl->rtekind != RTE_RELATION && tbl->rtekind != RTE_CTE)
        		return NULL;

        	restype = exprType((Node *) var);

        	grpcl = makeNode(SortGroupClause);
        	ressortgroupref++;

        	if (tbl->rtekind == RTE_RELATION)
        	{
        		ent = makeTargetEntry((Expr *) copyObject(var), var->varoattno,
        							  get_relid_attribute_name(tbl->relid, var->varoattno), false);
        	}
        	else
        	{
        		int plan_id;
        		int ndx;
        		ListCell *lc;
        		Plan *cte_plan;
        		TargetEntry *cte_ent = NULL;

        		/*
        		 * Note: cte_plan_ids can be shorter than cteList, if we are still working
        		 * on planning the CTEs (ie, this is a side-reference from another CTE).
        		 * So we mustn't use forboth here.
        		 */
        		ndx = 0;
        		foreach (lc, root->parse->cteList)
        		{
        			CommonTableExpr *cte = (CommonTableExpr *) lfirst(lc);

        			if (strcmp(cte->ctename, tbl->ctename) == 0)
        				break;
        			ndx++;
        		}
        		if (lc == NULL) /* shouldn't happen */
        			elog(ERROR, "could not find CTE \"%s\"", tbl->ctename);
        		if (ndx >= list_length(root->cte_plan_ids))
        			elog(ERROR, "could not find plan for CTE \"%s\"", tbl->ctename);
        		plan_id = list_nth_int(root->cte_plan_ids, ndx);
        		cte_plan = (Plan *) lfirst(list_nth_cell(root->glob->subplans, plan_id - 1));
        		cte_ent = (TargetEntry *) lfirst(list_nth_cell(cte_plan->targetlist, var->varattno - 1));
        		ent = makeTargetEntry((Expr *) copyObject(var), var->varoattno, cte_ent->resname, false);
        	}

        	ent->ressortgroupref = ressortgroupref;

        	subselect->targetList = lappend(subselect->targetList, ent);

        	varno = list_length(subselect->targetList);
        	ent->resno = varno;

        	/* determine the eqop and optional sortop */
        	get_sort_group_operators(restype,
        							 false, true, false,
        							 &sortop, &eqop, NULL,
        							 &hashable);

        	grpcl->tleSortGroupRef = ressortgroupref;
        	grpcl->eqop = eqop;
        	grpcl->sortop = sortop;
        	grpcl->nulls_first = false; /* OK with or without sortop */
        	grpcl->hashable = hashable;

        	subselect->groupClause = lappend(subselect->groupClause, grpcl);
        }

        /*
         * If we got Aggregation clause, since there is only one TargetList,
         * then we can use JOIN_LEFT_SEMI over JOIN_LEFT/JOIN_LEFT_SCALAR to
         * save more costs.
         */
        finalJoinType = JOIN_LEFT_SEMI;
	}

	/*
	 * Move sub-select to the parent query.
	 */
	pstate = make_parsestate(NULL);
	rte = addRangeTableEntryForSubquery(pstate,
										subselect,
										makeAlias("TARGETLIST_subquery", NIL),
										true,
										false);
	parse->rtable = lappend(parse->rtable, rte);

	rtr = makeNode(RangeTblRef);
	rtr->rtindex = list_length(parse->rtable);

	/*
	 * Form join node.
	 */
	joinExpr = makeNode(JoinExpr);
	joinExpr->jointype = finalJoinType;
	joinExpr->isNatural = false;
	joinExpr->larg = (Node *) root->parse->jointree;
	joinExpr->rarg = (Node *) rtr;
	joinExpr->usingClause = NIL;
	joinExpr->alias   = NULL;
	joinExpr->rtindex = 0; /* we don't need an RTE for it */
	joinExpr->quals   = NULL;

	/* Wrap join node in FromExpr as required. */
	parse->jointree = makeFromExpr(list_make1(joinExpr), NULL);

	/* Build a Var pointing to the subquery */
	target = (Node *)makeVarFromTargetEntry(rtr->rtindex,
											linitial(subselect->targetList));

	/* Add Coalesce(count,0) */
    if (count_agg)
    {
        CoalesceExpr *coalesce = makeNode(CoalesceExpr);
        Const *constExpr = makeConst(INT8OID, -1, InvalidOid, sizeof(int64),
        							 Int64GetDatum(0), false, true);

        coalesce->args = list_make2(target, constExpr);
        coalesce->coalescetype = INT8OID;
        target = (Node *) coalesce;
    }

	/* Replace sublink node with Result. */
	entry->expr = (Expr *)substitute_sublink_with_node((Node *)entry->expr,
													   sublink,
													   target);
	return entry;
}
#endif

static Expr *
convert_OR_EXIST_sublink_to_join(PlannerInfo *root, SubLink *sublink, Node **jtlink)
{
	JoinExpr *joinExpr;
	RangeTblRef *rtr;
	RangeTblEntry *rte;
	List *distinctColums = NIL;
	List *joinClause = NIL;
	ListCell *cell;
	Query *parse = root->parse;
	Query *subselect = (Query *)sublink->subselect;
	Node *whereClause;
	Expr *expr;
	NullTest *ntest;
	ParseState *pstate;
	List *fake_colnames = NIL;
	int rtindex;
	int subrtindex;
	int i;
	int ressortgroupref;
	int next_attno;

	Assert(sublink->subLinkType == EXISTS_SUBLINK);

	subselect = copyObject(subselect);
	simplify_EXISTS_query(root, subselect);

	whereClause = subselect->jointree->quals;
	subselect->jointree->quals = NULL;

	pstate = make_parsestate(NULL);
	rte = addRangeTableEntryForSubquery(pstate,
										subselect,
										makeAlias("EXIST_subquery", NIL),
										false,
										false);

	parse->rtable = lappend(parse->rtable, rte);
	rtindex = list_length(parse->rtable);
	rtr = makeNode(RangeTblRef);
	rtr->rtindex = rtindex;
	next_attno = 1;
	subselect->jointree->quals =
		get_or_exist_subquery_targetlist(root, whereClause, &distinctColums, &joinClause, &next_attno);
	ressortgroupref = 0;

	foreach (cell, distinctColums)
	{
		Oid sortop;
		Oid eqop;
		bool hashable;
		Oid restype;
		SortGroupClause *grpcl;
		TargetEntry *entry;

        subselect->targetList = append_var_to_subquery_targetlist((Var *)lfirst(cell),
                                                                  subselect->targetList, &entry);
		restype = exprType((Node *)entry->expr);
		get_sort_group_operators(restype,
								 false, true, false,
								 &sortop, &eqop, NULL,
								 &hashable);
		ressortgroupref++;
		entry->ressortgroupref = ressortgroupref;
		grpcl = makeNode(SortGroupClause);
		grpcl->tleSortGroupRef = ressortgroupref;
		grpcl->eqop = eqop;
		grpcl->sortop = sortop;
		grpcl->nulls_first = false; /* OK with or without sortop */
		grpcl->hashable = hashable;
		subselect->groupClause = lappend(subselect->groupClause, grpcl);
    }

	expr = (Expr *)makeBoolConst(true, false);
	subselect->targetList = lappend(subselect->targetList, (makeTargetEntry(expr,
																			list_length(subselect->targetList) + 1,
																			NULL,
																			false)));
	foreach (cell, subselect->targetList)
	{
		fake_colnames = lappend(fake_colnames, makeString(pstrdup("fake")));
	}
	rte->eref = makeAlias("EXIST_subquery", fake_colnames);

	joinExpr = makeNode(JoinExpr);
	joinExpr->jointype = JOIN_LEFT;
	joinExpr->isNatural = false;
	joinExpr->larg = (Node *)(*jtlink);
	joinExpr->rarg = (Node *)rtr;
	joinExpr->usingClause = NIL;
	joinExpr->alias = NULL;
	joinExpr->rtindex = 0; /* we don't need an RTE for it */

	if (list_length(joinClause) == 1)
		joinExpr->quals = (Node *)linitial(joinClause);
	else
		joinExpr->quals = (Node *)make_andclause(joinClause);

	*jtlink = (Node *)joinExpr;

	subrtindex = list_length(subselect->rtable);
	for (i = 1; i <= subrtindex; i++)
	{
		ChangeVarNodes(joinExpr->quals, i, rtindex, 0);
	}

	IncrementVarSublevelsUp(joinExpr->quals, -1, 1);
	ntest = makeNode(NullTest);
	ntest->arg = (Expr *)makeVar(rtindex,
								 list_length(subselect->targetList),
								 BOOLOID,
								 -1,
								 InvalidOid,
								 0);
	ntest->nulltesttype = IS_NOT_NULL;
	ntest->argisrow = false;
	ntest->location = -1;
	return (Expr *)ntest;
}

bool
check_or_exist_qual_pullupable(PlannerInfo *root, Node *node)
{
	ListCell *l = NULL;

	if (and_clause(node))
	{
		foreach (l, ((BoolExpr *)node)->args)
		{
			if (!check_or_exist_qual_pullupable(root, (Node *)lfirst(l)))
				return false;
		}
		return true;
	}
	else if (or_clause(node))
	{
		return pull_vars_of_level((Node *)lfirst(l), 1) == NIL;
	}
	else
	{
		List *vars = pull_vars_of_level(node, 1);
		if (vars == NIL)
			return true;

		if (IsA(node, OpExpr))
		{
			HeapTuple opertup;
			Form_pg_operator operform;
			char *oprname;

			OpExpr *expr = (OpExpr *)node;

			opertup = SearchSysCache1(OPEROID, ObjectIdGetDatum(expr->opno));
			if (!HeapTupleIsValid(opertup))
				return false;
				
			operform = (Form_pg_operator)GETSTRUCT(opertup);
			oprname = NameStr(operform->oprname);

			ReleaseSysCache(opertup);
			if (strcmp(oprname, "=") == 0 && list_length(expr->args) == 2)
				return true;
		}
		return false;
	}
	return true;
}

bool check_or_exist_sublink_pullupable(PlannerInfo *root, Node *node)
{
	Node    *whereClause;
	Query   *subselect;

	if(node == NULL)
		return false;
	
	subselect = (Query *)copyObject(((SubLink *)(node))->subselect);

	if (subselect->cteList)
		return false;
		
	if (!simplify_EXISTS_query(root, subselect))
		return false;
		
	if (subselect->jointree->fromlist == NIL)
		return false;

	whereClause = subselect->jointree->quals;
	subselect->jointree->quals = NULL;

	if (contain_vars_of_level((Node *)subselect, 1))
		return false;

	if (!contain_vars_of_level(whereClause, 1))
		return false;

	if (contain_volatile_functions(whereClause))
		return false;

	return true;
}
/*
  * try to convert all sublink to join or new query
  */
JoinExpr *
convert_ALL_sublink_to_join(PlannerInfo *root, SubLink *sublink,
                               Relids available_rels)
{// #lizard forgives
    JoinExpr   *result;
    Query       *parse = root->parse;
    Query       *subselect = (Query *) sublink->subselect;
    Node       *whereClause;
    Node       *quals;
    ListCell    *cell;
    Var         *var;
    Param       *param;
    int         varno;
    int            rtindex;
    ParseState *pstate;
    RangeTblEntry *rte;
    RangeTblRef *rtr;
    Relids        upper_varnos;
    List       *subquery_vars;
    bool       use_max = false;
    TargetEntry *ent = NULL;
    int        nEnt  = 0;
    List       *joinquals = NULL;

    subselect = (Query *)copyObject(sublink->subselect);

    /* subquery must be simple query */
    if (!simplify_ALL_query(root, subselect))
        return NULL;

    /* we can only handle '>' and '<' in testexpr now.. */
    if (IsA(sublink->testexpr, OpExpr))
    {
        HeapTuple    opertup;
        Form_pg_operator operform;
        char       *oprname;
        OpExpr     *expr = (OpExpr *)sublink->testexpr;

        opertup = SearchSysCache1(OPEROID, ObjectIdGetDatum(expr->opno));
        if (!HeapTupleIsValid(opertup))
            return NULL;
        
        operform = (Form_pg_operator) GETSTRUCT(opertup);
        oprname = NameStr(operform->oprname);

        ReleaseSysCache(opertup);

        if (strcmp(oprname, ">") == 0)
        {
            use_max = true;
        }
        else if (strcmp(oprname, "<") == 0)
        {
            use_max = false;
        }
        else
        {
            return NULL;
        }

        var = NULL;
        param = NULL;
        foreach(cell, expr->args)
        {
            Node *arg = lfirst(cell);

            if (IsA(arg, Var))
            {
                var = (Var *)arg;
            }
            else if (IsA(arg, Param))
            {
                param = (Param *)arg;
            }
        }

        if (!var || !param)
            return NULL;
    }
    else
        return NULL;

    /* subquery must return one column */
    foreach(cell, subselect->targetList)
    {
        TargetEntry *target = (TargetEntry *)lfirst(cell);

        if (target->resjunk)
            continue;

        nEnt++;
        ent = target;
    }

    if (nEnt != 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(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;

    /* correlated subquery must contain some vars of parent query */
    if (contain_vars_of_level((Node *) subselect, 1))
    {
        whereClause = subselect->jointree->quals;
        subselect->jointree->quals = 0;

        /* vars of parent query must be in whereclause */
        if (contain_vars_of_level((Node *) subselect, 1))
            return NULL;

        upper_varnos = pull_varnos_of_level(whereClause, 1);
        if (bms_is_empty(upper_varnos))
            return NULL;

        /* whereclause contains vars from different parent query */
        if (bms_num_members(upper_varnos) > 1)
            return NULL;
    
        /*
         * However, it can't refer to anything outside available_rels.
         */
        if (!bms_is_subset(upper_varnos, available_rels))
            return NULL;

        /* process 'op' and 'bool' expr only */
		if (contain_notexpr_or_neopexpr(whereClause, true, &joinquals))
            return NULL;

        if (contain_volatile_functions(whereClause))
            return NULL;

        /* we can not handle correlated subquery with groupby now. */
        if (subselect->groupClause)
            return NULL;

        if (!joinquals)
            return NULL;

        if (subselect->hasAggs)
        {
            /* 
              * whereclause can only be 'and' expr and 'op =' expr , this
              * has been checked before.
              */
            int offset = 0;
            int  ressortgroupref = 0;
            List *vars = NULL;
            OpExpr     *expr = (OpExpr *)copyObject(sublink->testexpr);
            
            vars = pull_vars_of_level((Node *)joinquals, 0);

            /* construct groupby clause */
            foreach(cell, vars)
            {
                Oid            sortop;
                Oid            eqop;
                bool        hashable;
                Oid         restype;
                SortGroupClause *grpcl;
                TargetEntry     *tent;
            
                Var *var = (Var *)lfirst(cell);

                RangeTblEntry *tbl = (RangeTblEntry *)list_nth(subselect->rtable, var->varno - 1);

                if (tbl->rtekind != RTE_RELATION)
                    return NULL;
                
                restype = exprType((Node *)var);

                grpcl = makeNode(SortGroupClause);

                ressortgroupref++;

                tent = makeTargetEntry((Expr *)copyObject(var), var->varoattno, get_relid_attribute_name(tbl->relid, var->varoattno), false);

                tent->ressortgroupref = ressortgroupref;

                subselect->targetList = lappend(subselect->targetList, tent);

                varno = list_length(subselect->targetList);

                tent->resno = varno;

                //var->varattno = var->varoattno = varno;

                /* determine the eqop and optional sortop */
                get_sort_group_operators(restype,
                                         false, true, false,
                                         &sortop, &eqop, NULL,
                                         &hashable);

                grpcl->tleSortGroupRef = ressortgroupref;
                grpcl->eqop = eqop;
                grpcl->sortop = sortop;
                grpcl->nulls_first = false; /* OK with or without sortop */
                grpcl->hashable = hashable;

                subselect->groupClause = lappend(subselect->groupClause, grpcl);
            }

            rtindex = list_length(parse->rtable);

            offset = rtindex;

            OffsetVarNodes(whereClause, rtindex, 0);

            IncrementVarSublevelsUp(whereClause, -1, 1);

            pstate = make_parsestate(NULL);

            rte = addRangeTableEntryForSubquery(pstate,
                                        subselect,
                                        makeAlias("ALL_subquery", NIL),
                                        false,
                                        false);

            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;

            add_vars_to_subquery_targetlist(whereClause, subselect, rtindex, offset);
            
            list_delete(expr->args, param);

            expr->args = lappend(expr->args, makeVarFromTargetEntry(rtindex, ent));

            quals = (Node *)makeBoolExpr(AND_EXPR, list_make2(expr, whereClause), 0);

            /*
             * And finally, build the JoinExpr node.
             */
            result = makeNode(JoinExpr);
            result->jointype = JOIN_INNER;
            result->isNatural = false;
            result->larg = NULL;        /* caller must fill this in */
            result->rarg = (Node *) rtr;
            result->usingClause = NIL;
            result->quals = quals;
            result->alias = NULL;
            result->rtindex = 0;        /* we don't need an RTE for it */

            return result;
        }
        else
        {
            /* 
              * whereclause can only be 'and' expr and 'op =' expr , this
              * has been checked before.
              */
            Aggref       *aggref = NULL;
            List       *aggfuncname = NULL;
            FuncDetailCode fdresult;
            Oid        actual_arg_types[FUNC_MAX_ARGS];
            Oid            rettype;
            Oid            funcid;
            Oid           *declared_arg_types;
            List       *argdefaults;
            bool        retset;
            int            nvargs;
            Oid            vatype;
            int  ressortgroupref = 0;
            List *vars = pull_vars_of_level((Node *)joinquals, 0);
            OpExpr     *expr = (OpExpr *)copyObject(sublink->testexpr);
            TargetEntry     *tent;
            int offset = 0;

            /* construct groupby clause */
            foreach(cell, vars)
            {
                Oid            sortop;
                Oid            eqop;
                bool        hashable;
                Oid         restype;
                SortGroupClause *grpcl;
                
                
                Var *var = (Var *)lfirst(cell);

                RangeTblEntry *tbl = (RangeTblEntry *)list_nth(subselect->rtable, var->varno - 1);

                if (tbl->rtekind != RTE_RELATION)
                    return NULL;
                
                restype = exprType((Node *)var);

                grpcl = makeNode(SortGroupClause);

                ressortgroupref++;

                tent = makeTargetEntry((Expr *)copyObject(var), var->varoattno, get_relid_attribute_name(tbl->relid, var->varoattno), false);

                tent->ressortgroupref = ressortgroupref;

                subselect->targetList = lappend(subselect->targetList, tent);

                varno = list_length(subselect->targetList);

                tent->resno = varno;

                //var->varattno = var->varoattno = varno;

                /* determine the eqop and optional sortop */
                get_sort_group_operators(restype,
                                         false, true, false,
                                         &sortop, &eqop, NULL,
                                         &hashable);

                grpcl->tleSortGroupRef = ressortgroupref;
                grpcl->eqop = eqop;
                grpcl->sortop = sortop;
                grpcl->nulls_first = false; /* OK with or without sortop */
                grpcl->hashable = hashable;

                subselect->groupClause = lappend(subselect->groupClause, grpcl);
            }

            /* have only one entry for rtable */
            rtindex = list_length(subselect->rtable);
            
            actual_arg_types[0] = exprType((Node *)ent->expr);

            /* construct agg function */
            if (use_max)
            {
                aggfuncname = lappend(aggfuncname, makeString("max"));
            }
            else
            {
                aggfuncname = lappend(aggfuncname, makeString("min"));
            }

            fdresult = func_get_detail(aggfuncname, list_make1(ent->expr), NULL, 1,
                           actual_arg_types,
                           true, true,
                           &funcid, &rettype, &retset,
                           &nvargs, &vatype,
                           &declared_arg_types, &argdefaults);

            if (fdresult != FUNCDETAIL_AGGREGATE)
                return NULL;

            /* make targetlist of subquery */
            aggref = makeNode(Aggref);

            aggref->aggfnoid = funcid;
            aggref->aggtype = rettype;
            /* aggcollid and inputcollid will be set by parse_collate.c */
            aggref->aggtranstype = InvalidOid;    /* will be set by planner */
            aggref->aggkind = AGGKIND_NORMAL;
            /* agglevelsup will be set by transformAggregateCall */
            aggref->aggsplit = AGGSPLIT_SIMPLE; /* planner might change this */

            aggref->aggargtypes = lappend_oid(aggref->aggargtypes, exprType((Node *)ent->expr));

            aggref->args = lappend(aggref->args, makeTargetEntry((Expr *)ent->expr, 1, NULL, false));

            if (use_max)
            {
                tent = makeTargetEntry((Expr *)aggref, 1, "max", false);
            }
            else
            {
                tent = makeTargetEntry((Expr *)aggref, 1, "min", false);
            }

            
            subselect->targetList = lappend(subselect->targetList, tent);

            varno = list_length(subselect->targetList);

            tent->resno = varno;

            subselect->hasAggs = true;

            rtindex = list_length(parse->rtable);

            offset = rtindex;

            OffsetVarNodes(whereClause, rtindex, 0);

            IncrementVarSublevelsUp(whereClause, -1, 1);

            pstate = make_parsestate(NULL);

            rte = addRangeTableEntryForSubquery(pstate,
                                        subselect,
                                        makeAlias("ALL_subquery", NIL),
                                        false,
                                        false);

            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;

            add_vars_to_subquery_targetlist(whereClause, subselect, rtindex, offset);
            
            list_delete(expr->args, param);

            expr->args = lappend(expr->args, makeVarFromTargetEntry(rtindex, tent));

            quals = (Node *)makeBoolExpr(AND_EXPR, list_make2(expr, whereClause), 0);

            /*
             * And finally, build the JoinExpr node.
             */
            result = makeNode(JoinExpr);
            result->jointype = JOIN_INNER;
            result->isNatural = false;
            result->larg = NULL;        /* caller must fill this in */
            result->rarg = (Node *) rtr;
            result->usingClause = NIL;
            result->quals = quals;
            result->alias = NULL;
            result->rtindex = 0;        /* we don't need an RTE for it */

            return result;
        }
    }
    /* uncorrelated subquery */
    else
    {
        /*
          * if subquery has aggs without groupby, subquery will get one rows output,
          * and we can transform to join directly
          */
        if (subselect->hasAggs && !subselect->groupClause)
        {
            /* Create a dummy ParseState for addRangeTableEntryForSubquery */
            pstate = make_parsestate(NULL);

            rte = addRangeTableEntryForSubquery(pstate,
                                subselect,
                                makeAlias("ALL_subquery", NIL),
                                false,
                                false);

            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_INNER;
            result->isNatural = false;
            result->larg = NULL;        /* caller must fill this in */
            result->rarg = (Node *) rtr;
            result->usingClause = NIL;
            result->quals = quals;
            result->alias = NULL;
            result->rtindex = 0;        /* we don't need an RTE for it */
            
            return result;
        }
        else
        {
            /*
              * subquery has groupby, we have to make decision according to
              * subquery's testexpr.
              * if it is '>', we use 'max' instead of ALL;
              * and if it is '<', we choose 'min'.
              */

            /* constrcut new query instead of ALL sublink */
            Aggref       *aggref = NULL;
            List       *aggfuncname = NULL;
            FuncDetailCode fdresult;
            Oid        actual_arg_types[FUNC_MAX_ARGS];
            Var        *aggArg = NULL;
            Oid            rettype;
            Oid            funcid;
            Oid           *declared_arg_types;
            List       *argdefaults;
            bool        retset;
            int            nvargs;
            Oid            vatype;
            
            Query *query = makeNode(Query);
            query->commandType = subselect->commandType;
            query->canSetTag   = subselect->canSetTag;
            query->querySource = subselect->querySource;
            query->hasAggs     = true;

            /* Create a dummy ParseState for addRangeTableEntryForSubquery */
            pstate = make_parsestate(NULL);

            rte = addRangeTableEntryForSubquery(pstate,
                                subselect,
                                makeAlias("ALL_subquery", NIL),
                                false,
                                false);

            query->rtable = lappend(query->rtable, rte);

            rtindex = list_length(query->rtable);

            /*
             * Form a RangeTblRef for the pulled-up sub-select.
             */
            rtr = makeNode(RangeTblRef);
            rtr->rtindex = rtindex;

            query->jointree = makeFromExpr(list_make1(rtr), NULL);

            aggArg = makeVarFromTargetEntry(rtindex, ent);

            actual_arg_types[0] = exprType((Node *)aggArg);

            /* construct agg function */
            if (use_max)
            {
                aggfuncname = lappend(aggfuncname, makeString("max"));
            }
            else
            {
                aggfuncname = lappend(aggfuncname, makeString("min"));
            }

            fdresult = func_get_detail(aggfuncname, list_make1(aggArg), NULL, 1,
                           actual_arg_types,
                           true, true,
                           &funcid, &rettype, &retset,
                           &nvargs, &vatype,
                           &declared_arg_types, &argdefaults);

            if (fdresult != FUNCDETAIL_AGGREGATE)
                return NULL;

            /* make targetlist of newquery */
            aggref = makeNode(Aggref);

            aggref->aggfnoid = funcid;
            aggref->aggtype = rettype;
            /* aggcollid and inputcollid will be set by parse_collate.c */
            aggref->aggtranstype = InvalidOid;    /* will be set by planner */
            aggref->aggkind = AGGKIND_NORMAL;
            /* agglevelsup will be set by transformAggregateCall */
            aggref->aggsplit = AGGSPLIT_SIMPLE; /* planner might change this */

            aggref->aggargtypes = lappend_oid(aggref->aggargtypes, exprType((Node *)aggArg));

            aggref->args = lappend(aggref->args, makeTargetEntry((Expr *)aggArg, 1, NULL, false));

            if (use_max)
            {
                query->targetList = lappend(query->targetList, makeTargetEntry((Expr *)aggref, 1, "max", false));
            }
            else
            {
                query->targetList = lappend(query->targetList, makeTargetEntry((Expr *)aggref, 1, "min", false));
            }

            rte = addRangeTableEntryForSubquery(pstate,
                                query,
                                makeAlias("temp", NIL),
                                false,
                                false);

            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,
                                                   query->targetList,
                                                   rtindex);

            /*
             * Build the new join's qual expression, replacing Params with these Vars.
             */
            quals = copyObject(sublink->testexpr);
            list_delete(((OpExpr *)quals)->args, param);
            ((OpExpr *)quals)->args = lappend(((OpExpr *)quals)->args, linitial(subquery_vars));
#if 0            
            quals = convert_testexpr(root, sublink->testexpr, subquery_vars);
#endif
            /*
             * And finally, build the JoinExpr node.
             */
            result = makeNode(JoinExpr);
            result->jointype = JOIN_INNER;
            result->isNatural = false;
            result->larg = NULL;        /* caller must fill this in */
            result->rarg = (Node *) rtr;
            result->usingClause = NIL;
            result->quals = quals;
            result->alias = NULL;
            result->rtindex = 0;        /* we don't need an RTE for it */
            
            return result;
        }
    }

    return NULL;
}

#endif
/*
 * 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)
{// #lizard forgives
    /*
     * 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)
{// #lizard forgives
    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);
    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;
    /* there's no "forfour" so we have to chase one of the lists manually */
    cc = list_head(opcollations);
    forthree(lc, leftargs, rc, rightargs, oc, opids)
    {
        Node       *leftarg = (Node *) lfirst(lc);
        Node       *rightarg = (Node *) lfirst(rc);
        Oid            opid = lfirst_oid(oc);
        Oid            opcollation = lfirst_oid(cc);
        Param       *param;

        cc = lnext(cc);
        param = generate_new_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)
{// #lizard forgives
    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)
{// #lizard forgives
    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 or aggregate 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 or Aggref
     * 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;
    }

    /*
     * 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 (and_clause(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 (and_clause(newarg))
                newargs = list_concat(newargs, ((BoolExpr *) newarg)->args);
            else
                newargs = lappend(newargs, newarg);
        }
        return (Node *) make_andclause(newargs);
    }

    if (or_clause(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 (or_clause(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->nParamExec == 0)
        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 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;
    }

    /* 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, root->outer_params, NULL);
}

/*
 * Recursive processing of all nodes in the plan tree
 *
 * 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, Bitmapset *valid_params,
              Bitmapset *scan_params)
{// #lizard forgives
    finalize_primnode_context context;
    int            locally_added_param;
    Bitmapset  *nestloop_params;
    Bitmapset  *initExtParam;
    Bitmapset  *initSetParam;
    Bitmapset  *child_params;
    ListCell   *l;
    List       *initPlan;

    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;

    /*
     * Usually initPlans are attached to the top level plan, but in Postgres-XL
     * we might add a RemoteSubplan plan on top the top level plan. If we don't
     * look at the initPlans, we might fail to conclude that param references
     * are valid (issue #81).
     */
    initPlan = plan->initPlan;
    if ((initPlan == NULL) && IsA(plan, RemoteSubplan) && plan->lefttree)
        initPlan = plan->lefttree->initPlan;

    foreach(l, 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);

    /* 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)->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_SubqueryScan:
            {
                SubqueryScan *sscan = (SubqueryScan *) plan;
                RelOptInfo *rel;

                /* We must run SS_finalize_plan on the subquery */
                rel = find_base_rel(root, sscan->scan.scanrelid);
                SS_finalize_plan(rel->subroot, sscan->subplan);

                /* 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),
                                                      valid_params,
                                                      scan_params));
                }
            }
            break;

        case T_ModifyTable:
            {
                ModifyTable *mtplan = (ModifyTable *) plan;
                ListCell   *l;

                /* 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 */
                foreach(l, mtplan->plans)
                {
                    context.paramids =
                        bms_add_members(context.paramids,
                                        finalize_plan(root,
                                                      (Plan *) lfirst(l),
                                                      valid_params,
                                                      scan_params));
                }
            }
            break;
#ifdef PGXC
        case T_RemoteQuery:
            //PGXCTODO
            context.paramids = bms_add_members(context.paramids, scan_params);
            break;
#endif

#ifdef XCP
        case T_RemoteSubplan:
            break;
#endif

        case T_Append:
            {
                ListCell   *l;

                foreach(l, ((Append *) plan)->appendplans)
                {
                    context.paramids =
                        bms_add_members(context.paramids,
                                        finalize_plan(root,
                                                      (Plan *) lfirst(l),
                                                      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),
                                                      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),
                                                      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),
                                                      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_ProjectSet:
        case T_Hash:
        case T_Material:
        case T_Sort:
        case T_Unique:
        case T_Gather:
        case T_GatherMerge:
        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,
                                 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,
                                     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,
                                     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_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_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);
}
/*
 * SS_remote_attach_initplans
 *
 * recursively look into a plantree, find any RemoteSubplan and
 * attach params id that generated from init-plan of this query.
 */
void
SS_remote_attach_initplans(PlannerInfo *root, Plan *plan)
{
	ListCell   *lc;
	
	if (plan == NULL)
		return;
	
	if (IsA(plan, RemoteSubplan))
	{
		ListCell *plan_lc, *param_lc;
		RemoteSubplan *rsplan = (RemoteSubplan *) plan;
		Assert(rsplan->initPlanParams == NULL);
		foreach(plan_lc, root->init_plans)
		{
			SubPlan *initplan = (SubPlan *) lfirst(plan_lc);
			foreach(param_lc, initplan->setParam)
			{
				rsplan->initPlanParams = 
					bms_add_member(rsplan->initPlanParams, lfirst_int(param_lc));
			}
		}
	}
	
	switch (nodeTag(plan))
	{
		case T_SubqueryScan:
		{
			SubqueryScan *sscan = (SubqueryScan *) plan;
			RelOptInfo *rel;
			
			rel = find_base_rel(root, sscan->scan.scanrelid);
			SS_remote_attach_initplans(rel->subroot, sscan->subplan);
		}
			break;
		case T_CustomScan:
		{
			foreach(lc, ((CustomScan *) plan)->custom_plans)
				SS_remote_attach_initplans(root, (Plan *) lfirst(lc));
		}
			break;
		case T_ModifyTable:
		{
			foreach(lc, ((ModifyTable *) plan)->plans)
				SS_remote_attach_initplans(root, (Plan *) lfirst(lc));
		}
			break;
		case T_Append:
		{
			foreach(lc, ((Append *) plan)->appendplans)
				SS_remote_attach_initplans(root, (Plan *) lfirst(lc));
		}
			break;
		case T_MergeAppend:
		{
			foreach(lc, ((MergeAppend *) plan)->mergeplans)
				SS_remote_attach_initplans(root, (Plan *) lfirst(lc));
		}
			break;
		case T_BitmapAnd:
		{
			foreach(lc, ((BitmapAnd *) plan)->bitmapplans)
				SS_remote_attach_initplans(root, (Plan *) lfirst(lc));
		}
			break;
		case T_BitmapOr:
		{
			foreach(lc, ((BitmapOr *) plan)->bitmapplans)
				SS_remote_attach_initplans(root, (Plan *) lfirst(lc));
		}
			break;
		default:
			break;
	}
	
	/* Process left and right child plans, if any */
	SS_remote_attach_initplans(root, plan->lefttree);
	SS_remote_attach_initplans(root, plan->righttree);
}