prepjointree.c 43.8 KB
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/*-------------------------------------------------------------------------
 *
 * prepjointree.c
 *	  Planner preprocessing for subqueries and join tree manipulation.
 *
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 * NOTE: the intended sequence for invoking these operations is
 *		pull_up_IN_clauses
 *		pull_up_subqueries
 *		do expression preprocessing (including flattening JOIN alias vars)
 *		reduce_outer_joins
 *
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 *
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 * In PostgreSQL, there is code here to do with pulling up "simple UNION ALLs".
 * In GPDB, there is no such thing as a simple UNION ALL as locus of the relations
 * may be different, so all that has been removed.
 *
 *
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 * Portions Copyright (c) 2006-2008, Greenplum inc
 * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
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 * Portions Copyright (c) 1994, Regents of the University of California
 *
 *
 * IDENTIFICATION
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 *	  $PostgreSQL: pgsql/src/backend/optimizer/prep/prepjointree.c,v 1.55 2008/10/04 21:56:53 tgl Exp $
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 *
 *-------------------------------------------------------------------------
 */
#include "postgres.h"

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#include "nodes/makefuncs.h"
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#include "optimizer/clauses.h"
#include "optimizer/prep.h"
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#include "optimizer/subselect.h"
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#include "optimizer/tlist.h"
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#include "optimizer/var.h"
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#include "parser/parse_expr.h"
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#include "parser/parsetree.h"
#include "rewrite/rewriteManip.h"

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#include "cdb/cdbsubselect.h"           /* cdbsubselect_flatten_sublinks() */

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typedef struct reduce_outer_joins_state
{
	Relids		relids;			/* base relids within this subtree */
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	bool		contains_outer; /* does subtree contain outer join(s)? */
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	List	   *sub_states;		/* List of states for subtree components */
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} reduce_outer_joins_state;
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static void pull_up_fromlist_subqueries(PlannerInfo    *root,
                                        List          **inout_fromlist,
				                        bool            below_outer_join);
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static Node *pull_up_simple_subquery(PlannerInfo *root, Node *jtnode,
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						RangeTblEntry *rte,
						bool below_outer_join,
						bool append_rel_member);
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bool is_simple_subquery(PlannerInfo *root, Query *subquery);
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static bool has_nullable_targetlist(Query *subquery);
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static bool is_safe_append_member(Query *subquery);
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static void resolvenew_in_jointree(Node *jtnode, int varno,
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					   RangeTblEntry *rte, List *subtlist);
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static reduce_outer_joins_state *reduce_outer_joins_pass1(Node *jtnode);
static void reduce_outer_joins_pass2(Node *jtnode,
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						 reduce_outer_joins_state *state,
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						 PlannerInfo *root,
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						 Relids nonnullable_rels);
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static void fix_in_clause_relids(List *in_info_list, int varno,
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					 Relids subrelids);
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static void fix_append_rel_relids(List *append_rel_list, int varno,
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					  Relids subrelids);
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static Node *find_jointree_node_for_rel(Node *jtnode, int relid);
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static bool is_simple_union_all_recurse(Node *setOp, Query *setOpQuery, List *colTypes);
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extern void UpdateScatterClause(Query *query, List *newtlist);
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/*
 * pull_up_IN_clauses
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 *		Attempt to pull up top-level IN clauses to be treated like joins.
 *
 * A clause "foo IN (sub-SELECT)" appearing at the top level of WHERE can
 * be processed by pulling the sub-SELECT up to become a rangetable entry
 * and handling the implied equality comparisons as join operators (with
 * special join rules).
 * This optimization *only* works at the top level of WHERE, because
 * it cannot distinguish whether the IN ought to return FALSE or NULL in
 * cases involving NULL inputs.  This routine searches for such clauses
 * and does the necessary parsetree transformations if any are found.
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 *
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 * This routine has to run before preprocess_expression(), so the WHERE
 * clause is not yet reduced to implicit-AND format.  That means we need
 * to recursively search through explicit AND clauses, which are
 * probably only binary ANDs.  We stop as soon as we hit a non-AND item.
 *
 * Returns the possibly-modified version of the given qual-tree node.
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 */
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Node *
pull_up_IN_clauses(PlannerInfo * root, List **rtrlist_inout, Node *node)
{
	if (node == NULL)
		return NULL;
	if (IsA(node, SubLink))
	{
		SubLink    *sublink = (SubLink *) node;
		Node	   *subst;

		/* Is it a convertible IN clause?  If not, return it as-is */
		subst = convert_sublink_to_join(root, rtrlist_inout, sublink);
		return subst;
	}
	if (and_clause(node))
	{
		List	   *newclauses = NIL;
		ListCell   *l;

		foreach(l, ((BoolExpr *) node)->args)
		{
			Node	   *oldclause = (Node *) lfirst(l);
			Node	   *newclause = pull_up_IN_clauses(root, rtrlist_inout, oldclause);

			if (newclause)
				newclauses = lappend(newclauses, newclause);
		}
		return (Node *) make_ands_explicit(newclauses);
	}
	if (not_clause(node))
	{
		Node	   *arg = (Node *) get_notclausearg((Expr *) node);

		/*
		 *	 We normalize NOT subqueries using the following axioms:
		 *
		 *		 val NOT IN (subq)		 =>  val <> ALL (subq)
		 *		 NOT val op ANY (subq)	 =>  val op' ALL (subq)
		 *		 NOT val op ALL (subq)	 =>  val op' ANY (subq)
		 */

		if (IsA(arg, SubLink))
		{
			SubLink    *sublink = (SubLink *) arg;

			if (sublink->subLinkType == ANY_SUBLINK)
			{
				sublink->subLinkType = ALL_SUBLINK;
				sublink->testexpr = (Node *) canonicalize_qual(
									 make_notclause((Expr *) sublink->testexpr));
			}
			else if (sublink->subLinkType == ALL_SUBLINK)
			{
				sublink->subLinkType = ANY_SUBLINK;
				sublink->testexpr = (Node *) canonicalize_qual(
									 make_notclause((Expr *) sublink->testexpr));
			}
			else if (sublink->subLinkType == EXISTS_SUBLINK)
			{
				sublink->subLinkType = NOT_EXISTS_SUBLINK;
			}
			else
			{
				return node;	/* do nothing for other sublinks */
			}

			return (Node *) pull_up_IN_clauses(root, rtrlist_inout, (Node *) sublink);
		}
		else if (not_clause(arg))
		{
			/* NOT NOT (expr) => (expr)  */
			return (Node *) pull_up_IN_clauses(root, rtrlist_inout,
									(Node *) get_notclausearg((Expr *) arg));
		}
		else if (or_clause(arg))
		{
			/* NOT OR (expr1) (expr2) => (expr1) AND (expr2) */
			return (Node *) pull_up_IN_clauses(root, rtrlist_inout,
									(Node *) canonicalize_qual((Expr *) node));
			
		}
	}

	/**
	 * (expr) op SUBLINK
	 */
	if (IsA(node, OpExpr))
	{
		OpExpr *opexp = (OpExpr *) node;

		if (list_length(opexp->args) == 2)
		{
			/**
			 * Check if second arg is sublink
			 */
			Node *rarg = list_nth(opexp->args, 1);

			if (IsA(rarg, SubLink))
			{
				return (Node *) convert_EXPR_to_join(root, rtrlist_inout, opexp);
			}
		}
	}
	/* Stop if not an AND */
	return node;
}
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/*
 * pull_up_subqueries
 *		Look for subqueries in the rangetable that can be pulled up into
 *		the parent query.  If the subquery has no special features like
 *		grouping/aggregation then we can merge it into the parent's jointree.
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 *		Also, subqueries that are simple UNION ALL structures can be
 *		converted into "append relations".
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 *
 * below_outer_join is true if this jointree node is within the nullable
 * side of an outer join.  This restricts what we can do.
 *
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 * append_rel_member is true if we are looking at a member subquery of
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 * an append relation.	This puts some different restrictions on what
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 * we can do.
 *
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 * A tricky aspect of this code is that if we pull up a subquery we have
 * to replace Vars that reference the subquery's outputs throughout the
 * parent query, including quals attached to jointree nodes above the one
 * we are currently processing!  We handle this by being careful not to
 * change the jointree structure while recursing: no nodes other than
 * subquery RangeTblRef entries will be replaced.  Also, we can't turn
 * ResolveNew loose on the whole jointree, because it'll return a mutated
 * copy of the tree; we have to invoke it just on the quals, instead.
 */
Node *
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pull_up_subqueries(PlannerInfo *root, Node *jtnode,
				   bool below_outer_join, bool append_rel_member)
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{
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	if (jtnode == NULL)
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		return NULL;
	if (IsA(jtnode, RangeTblRef))
	{
		int			varno = ((RangeTblRef *) jtnode)->rtindex;
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		RangeTblEntry *rte = rt_fetch(varno, root->parse->rtable);
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		/*
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		 * Is this a subquery RTE, and if so, is the subquery simple enough to
		 * pull up?  (If not, do nothing at this node.)
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		 *
		 * If we are inside an outer join, only pull up subqueries whose
		 * targetlists are nullable --- otherwise substituting their tlist
		 * entries for upper Var references would do the wrong thing (the
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		 * results wouldn't become NULL when they're supposed to).
		 *
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		 * XXX This could be improved by generating pseudo-variables for such
		 * expressions; we'd have to figure out how to get the pseudo-
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		 * variables evaluated at the right place in the modified plan tree.
		 * Fix it someday.
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		 *
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		 * If we are looking at an append-relation member, we can't pull it up
		 * unless is_safe_append_member says so.
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		 */
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		if (rte->rtekind == RTE_SUBQUERY &&
			!rte->forceDistRandom &&
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			is_simple_subquery(root, rte->subquery) &&
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			(!below_outer_join || has_nullable_targetlist(rte->subquery)) &&
			(!append_rel_member || is_safe_append_member(rte->subquery)))
			return pull_up_simple_subquery(root, jtnode, rte,
										   below_outer_join,
										   append_rel_member);
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		/* PG:
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		 * Alternatively, is it a simple UNION ALL subquery?  If so, flatten
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		 * into an "append relation".  We can do this regardless of
		 * nullability considerations since this transformation does not
		 * result in propagating non-Var expressions into upper levels of the
		 * query.
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		 *
		 * It's also safe to do this regardless of whether this query is
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		 * itself an appendrel member.	(If you're thinking we should try to
		 * flatten the two levels of appendrel together, you're right; but we
		 * handle that in set_append_rel_pathlist, not here.)
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		 * 
		 * GPDB: 
		 * Flattening to an append relation works in PG but is not safe to do in GPDB. 
		 * A "simple" UNION ALL may involve relations with different loci and would require resolving
		 * locus issues. It is preferable to avoid pulling up simple UNION ALL in GPDB.
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		 */
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	}
	else if (IsA(jtnode, FromExpr))
	{
		FromExpr   *f = (FromExpr *) jtnode;

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		Assert(!append_rel_member);
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        pull_up_fromlist_subqueries(root, &f->fromlist, below_outer_join);
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	}
	else if (IsA(jtnode, JoinExpr))
	{
		JoinExpr   *j = (JoinExpr *) jtnode;

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		Assert(!append_rel_member);
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		/* Recurse, being careful to tell myself when inside outer join */
		switch (j->jointype)
		{
			case JOIN_INNER:
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				j->larg = pull_up_subqueries(root, j->larg,
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											 below_outer_join, false);
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				j->rarg = pull_up_subqueries(root, j->rarg,
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											 below_outer_join, false);
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				break;
			case JOIN_LEFT:
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			case JOIN_LASJ:
			case JOIN_LASJ_NOTIN:
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				j->larg = pull_up_subqueries(root, j->larg,
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											 below_outer_join, false);
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				j->rarg = pull_up_subqueries(root, j->rarg,
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											 true, false);
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				break;
			case JOIN_FULL:
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				j->larg = pull_up_subqueries(root, j->larg,
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											 true, false);
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				j->rarg = pull_up_subqueries(root, j->rarg,
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											 true, false);
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				break;
			case JOIN_RIGHT:
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				j->larg = pull_up_subqueries(root, j->larg,
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											 true, false);
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				j->rarg = pull_up_subqueries(root, j->rarg,
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											 below_outer_join, false);
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				break;
			default:
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				elog(ERROR, "unrecognized join type: %d",
					 (int) j->jointype);
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				break;
		}
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        /*
         * CDB: If subqueries from the JOIN...ON search condition were
         * flattened, 'subqfromlist' is a list of RangeTblRef nodes to be
         * included in the cross product with larg and rarg.  Try to pull up
         * the referenced subqueries.  For outer joins, let below_outer_join
         * be true, because the subquery tables belong in the null-augmented
         * side of the JOIN (right side of LEFT JOIN).
         */
        if (j->subqfromlist)
            pull_up_fromlist_subqueries(root, &j->subqfromlist,
                                        below_outer_join || (j->jointype != JOIN_INNER));
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	}
	else
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		elog(ERROR, "unrecognized node type: %d",
			 (int) nodeTag(jtnode));
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	return jtnode;
}

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/*
 * pull_up_fromlist_subqueries
 *		Attempt to pull up subqueries in a List of jointree nodes.
 */
static void
pull_up_fromlist_subqueries(PlannerInfo    *root,
                            List          **inout_fromlist,
				            bool            below_outer_join)
{
    ListCell   *l;

    foreach(l, *inout_fromlist)
    {
        Node   *oldkid = (Node *)lfirst(l);
        Node   *newkid = pull_up_subqueries(root, oldkid,
											below_outer_join, false);

        lfirst(l) = newkid;
    }
}                               /* pull_up_fromlist_subqueries */


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/*
 * pull_up_simple_subquery
 *		Attempt to pull up a single simple subquery.
 *
 * jtnode is a RangeTblRef that has been tentatively identified as a simple
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 * subquery by pull_up_subqueries.	We return the replacement jointree node,
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 * or jtnode itself if we determine that the subquery can't be pulled up after
 * all.
 */
static Node *
pull_up_simple_subquery(PlannerInfo *root, Node *jtnode, RangeTblEntry *rte,
						bool below_outer_join, bool append_rel_member)
{
	Query	   *parse = root->parse;
	int			varno = ((RangeTblRef *) jtnode)->rtindex;
	Query	   *subquery;
	PlannerInfo *subroot;
	int			rtoffset;
	List	   *subtlist;
	ListCell   *rt;
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    ListCell   *cell;
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	/*
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	 * Need a modifiable copy of the subquery to hack on.  Even if we didn't
	 * sometimes choose not to pull up below, we must do this to avoid
	 * problems if the same subquery is referenced from multiple jointree
	 * items (which can't happen normally, but might after rule rewriting).
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	 */
	subquery = copyObject(rte->subquery);

	/*
	 * Create a PlannerInfo data structure for this subquery.
	 *
	 * NOTE: the next few steps should match the first processing in
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	 * subquery_planner().	Can we refactor to avoid code duplication, or
	 * would that just make things uglier?
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	 */
	subroot = makeNode(PlannerInfo);
	subroot->parse = subquery;
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	subroot->glob = root->glob;
	subroot->query_level = root->query_level;
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	subroot->parent_root = root->parent_root;
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	subroot->planner_cxt = CurrentMemoryContext;
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	subroot->init_plans = NIL;
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	subroot->cte_plan_ids = NIL;
	subroot->eq_classes = NIL;
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	subroot->in_info_list = NIL;
	subroot->append_rel_list = NIL;
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	subroot->hasRecursion = false;
	subroot->wt_param_id = -1;
	subroot->non_recursive_plan = NULL;

	/* No CTEs to worry about */
	Assert(subquery->cteList == NIL);
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	subroot->list_cteplaninfo = NIL;
	if (subroot->parse->cteList != NIL)
	{
		subroot->list_cteplaninfo = init_list_cteplaninfo(list_length(subroot->parse->cteList));
	}

    /* CDB: Stash subquery jointree relids before flattening subqueries. */
    subroot->currlevel_relids = get_relids_in_jointree((Node *)subquery->jointree);
    
    /* Ensure that jointree has been normalized. See normalize_query_jointree_mutator() */
    AssertImply(subquery->jointree->fromlist, list_length(subquery->jointree->fromlist) == 1);
    
    subroot->config = CopyPlannerConfig(root->config);
	/* CDB: Clear fallback */
	subroot->config->mpp_trying_fallback_plan = false;

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	/*
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	 * Pull up any IN clauses within the subquery's WHERE, so that we don't
	 * leave unoptimized INs behind.
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	 */
	if (subquery->hasSubLinks)
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        cdbsubselect_flatten_sublinks(subroot, (Node *)subquery);
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	/*
	 * Recursively pull up the subquery's subqueries, so that
	 * pull_up_subqueries' processing is complete for its jointree and
	 * rangetable.
	 *
	 * Note: below_outer_join = false is correct here even if we are within an
	 * outer join in the upper query; the lower query starts with a clean
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	 * slate for outer-join semantics.	Likewise, we say we aren't handling an
	 * appendrel member.
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	 */
	subquery->jointree = (FromExpr *)
		pull_up_subqueries(subroot, (Node *) subquery->jointree, false, false);

	/*
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	 * Now we must recheck whether the subquery is still simple enough to pull
	 * up.	If not, abandon processing it.
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	 *
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	 * We don't really need to recheck all the conditions involved, but it's
	 * easier just to keep this "if" looking the same as the one in
	 * pull_up_subqueries.
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	 */
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	if (is_simple_subquery(root, subquery) &&
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		(!below_outer_join || has_nullable_targetlist(subquery)) &&
		(!append_rel_member || is_safe_append_member(subquery)))
	{
		/* good to go */
	}
	else
	{
		/*
		 * Give up, return unmodified RangeTblRef.
		 *
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		 * Note: The work we just did will be redone when the subquery gets
		 * planned on its own.	Perhaps we could avoid that by storing the
		 * modified subquery back into the rangetable, but I'm not gonna risk
		 * it now.
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		 */
		return jtnode;
	}

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    /* CDB: If parent RTE belongs to subquery's query level, children do too. */
    foreach (cell, subroot->append_rel_list)
    {
        AppendRelInfo  *appinfo = (AppendRelInfo *)lfirst(cell);

        if (bms_is_member(appinfo->parent_relid, subroot->currlevel_relids))
            subroot->currlevel_relids = bms_add_member(subroot->currlevel_relids,
                                                       appinfo->child_relid);
    }

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	/*
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	 * Adjust level-0 varnos in subquery so that we can append its rangetable
	 * to upper query's.  We have to fix the subquery's in_info_list and
	 * append_rel_list, as well.
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	 */
	rtoffset = list_length(parse->rtable);
	OffsetVarNodes((Node *) subquery, rtoffset, 0);
	OffsetVarNodes((Node *) subroot->in_info_list, rtoffset, 0);
	OffsetVarNodes((Node *) subroot->append_rel_list, rtoffset, 0);

	/*
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	 * Upper-level vars in subquery are now one level closer to their parent
	 * than before.
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	 */
	IncrementVarSublevelsUp((Node *) subquery, -1, 1);
	IncrementVarSublevelsUp((Node *) subroot->in_info_list, -1, 1);
	IncrementVarSublevelsUp((Node *) subroot->append_rel_list, -1, 1);

	/*
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	 * Replace all of the top query's references to the subquery's outputs
	 * with copies of the adjusted subtlist items, being careful not to
	 * replace any of the jointree structure. (This'd be a lot cleaner if we
	 * could use query_tree_mutator.)
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	 */
	subtlist = subquery->targetList;
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	List *newTList = (List *)
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		ResolveNew((Node *) parse->targetList,
				   varno, 0, rte,
				   subtlist, CMD_SELECT, 0);
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	if (parse->scatterClause)
	{
		UpdateScatterClause(parse, newTList);
	}

	parse->targetList = newTList;

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	parse->returningList = (List *)
		ResolveNew((Node *) parse->returningList,
				   varno, 0, rte,
				   subtlist, CMD_SELECT, 0);
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	resolvenew_in_jointree((Node *) parse->jointree, varno,
						   rte, subtlist);
	Assert(parse->setOperations == NULL);
	parse->havingQual =
		ResolveNew(parse->havingQual,
				   varno, 0, rte,
				   subtlist, CMD_SELECT, 0);
	root->in_info_list = (List *)
		ResolveNew((Node *) root->in_info_list,
				   varno, 0, rte,
				   subtlist, CMD_SELECT, 0);
	root->append_rel_list = (List *)
		ResolveNew((Node *) root->append_rel_list,
				   varno, 0, rte,
				   subtlist, CMD_SELECT, 0);

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	if (parse->windowClause)
	{
		foreach(cell, parse->windowClause)
		{
			WindowSpec *win_spec = (WindowSpec *)lfirst(cell);
			if (win_spec->frame)
			{
				WindowFrame *frame = win_spec->frame;
				
				if (frame->trail)
					frame->trail->val = 
						ResolveNew((Node *)frame->trail->val,
								   varno, 0, rte,
								   subtlist, CMD_SELECT, 0);
				if (frame->lead)
					frame->lead->val =
						ResolveNew((Node *)frame->lead->val,
								   varno, 0, rte,
								   subtlist, CMD_SELECT, 0);
			}
		}
	}

580 581 582 583 584 585 586 587 588
	foreach(rt, parse->rtable)
	{
		RangeTblEntry *otherrte = (RangeTblEntry *) lfirst(rt);

		if (otherrte->rtekind == RTE_JOIN)
			otherrte->joinaliasvars = (List *)
				ResolveNew((Node *) otherrte->joinaliasvars,
						   varno, 0, rte,
						   subtlist, CMD_SELECT, 0);
589 590 591 592 593 594 595 596 597 598 599 600

		else if (otherrte->rtekind == RTE_SUBQUERY && rte != otherrte)
		{
			otherrte->subquery = (Query *)
				ResolveNew((Node *) otherrte->subquery,
							varno, 1, rte, /* here the sublevels_up can only be 1, because if larger than 1,
											  then the sublink is multilevel correlated, and cannot be pulled
											  up to be a subquery range table; while on the other hand, we
											  cannot directly put a subquery which refer to other relations
											  of the same level after FROM. */
							subtlist, CMD_SELECT, 0);
		}
601 602 603
	}

	/*
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Bruce Momjian 已提交
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	 * Now append the adjusted rtable entries to upper query. (We hold off
	 * until after fixing the upper rtable entries; no point in running that
	 * code on the subquery ones too.)
607 608 609 610
	 */
	parse->rtable = list_concat(parse->rtable, subquery->rtable);

	/*
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Bruce Momjian 已提交
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	 * Pull up any FOR UPDATE/SHARE markers, too.  (OffsetVarNodes already
	 * adjusted the marker rtindexes, so just concat the lists.)
613 614 615
	 */
	parse->rowMarks = list_concat(parse->rowMarks, subquery->rowMarks);

616 617 618 619 620 621 622 623 624 625 626 627 628 629
    /*
     * CDB: Fix current query level's FROM clause relid set if the subquery
     * was in the FROM clause of current query (not a flattened sublink).
     */
    if (bms_is_member(varno, root->currlevel_relids))
    {
        int     subrelid;

        root->currlevel_relids = bms_del_member(root->currlevel_relids, varno);
        bms_foreach(subrelid, subroot->currlevel_relids)
            root->currlevel_relids = bms_add_member(root->currlevel_relids,
                                                    subrelid + rtoffset);
    }

630
	/*
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Bruce Momjian 已提交
631 632 633
	 * We also have to fix the relid sets of any parent InClauseInfo nodes.
	 * (This could perhaps be done by ResolveNew, but it would clutter that
	 * routine's API unreasonably.)
634
	 *
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Bruce Momjian 已提交
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	 * Likewise, relids appearing in AppendRelInfo nodes have to be fixed (but
	 * we took care of their translated_vars lists above).	We already checked
	 * that this won't require introducing multiple subrelids into the
	 * single-slot AppendRelInfo structs.
639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657
	 */
	if (root->in_info_list || root->append_rel_list)
	{
		Relids		subrelids;

		subrelids = get_relids_in_jointree((Node *) subquery->jointree);
		fix_in_clause_relids(root->in_info_list, varno, subrelids);
		fix_append_rel_relids(root->append_rel_list, varno, subrelids);
	}

	/*
	 * And now add any subquery InClauseInfos and AppendRelInfos to our lists.
	 */
	root->in_info_list = list_concat(root->in_info_list,
									 subroot->in_info_list);
	root->append_rel_list = list_concat(root->append_rel_list,
										subroot->append_rel_list);

	/*
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	 * We don't have to do the equivalent bookkeeping for outer-join info,
	 * because that hasn't been set up yet.
660 661 662 663 664 665 666 667 668 669
	 */
	Assert(root->oj_info_list == NIL);
	Assert(subroot->oj_info_list == NIL);

	/*
	 * Miscellaneous housekeeping.
	 */
	parse->hasSubLinks |= subquery->hasSubLinks;
	/* subquery won't be pulled up if it hasAggs, so no work there */

670 671 672 673 674 675 676 677 678 679

    /*
     * CDB: Wipe old RTE so subquery parse tree won't be sent to QEs.
     */
    Assert(rte->rtekind == RTE_SUBQUERY);
    rte->rtekind = RTE_VOID;
    rte->subquery = NULL;
    rte->alias = NULL;
    rte->eref = NULL;

680
	/*
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	 * Return the adjusted subquery jointree to replace the RangeTblRef entry
	 * in parent's jointree.
683 684 685 686 687
	 */
	return (Node *) subquery->jointree;
}


688 689 690 691 692
/*
 * is_simple_subquery
 *	  Check a subquery in the range table to see if it's simple enough
 *	  to pull up into the parent query.
 */
693
bool
694
is_simple_subquery(PlannerInfo *root, Query *subquery)
695 696 697 698 699 700
{
	/*
	 * Let's just make sure it's a valid subselect ...
	 */
	if (!IsA(subquery, Query) ||
		subquery->commandType != CMD_SELECT ||
701
		subquery->utilityStmt != NULL ||
702
		subquery->intoClause != NULL)
703
		elog(ERROR, "subquery is bogus");
704 705

	/*
706 707
	 * 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
708 709 710 711 712 713
	 * redesign...
	 */
	if (subquery->setOperations)
		return false;

	/*
714 715
	 * Can't pull up a subquery involving grouping, aggregation, sorting,
	 * limiting, or WITH.  (XXX WITH could possibly be allowed later)
716 717
	 */
	if (subquery->hasAggs ||
718
	    subquery->hasWindFuncs ||
719 720
		subquery->groupClause ||
		subquery->havingQual ||
721
		subquery->windowClause ||
722 723 724
		subquery->sortClause ||
		subquery->distinctClause ||
		subquery->limitOffset ||
725 726 727
		subquery->limitCount ||
		subquery->cteList ||
		root->parse->cteList)
728 729 730
		return false;

	/*
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Bruce Momjian 已提交
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	 * Don't pull up a subquery that has any set-returning functions in its
	 * targetlist.	Otherwise we might well wind up inserting set-returning
	 * functions into places where they mustn't go, such as quals of higher
	 * queries.
735 736
	 */
	if (expression_returns_set((Node *) subquery->targetList))
737 738 739 740
		return false;

	/*
	 * Don't pull up a subquery that has any volatile functions in its
B
Bruce Momjian 已提交
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	 * 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.
744 745
	 */
	if (contain_volatile_functions((Node *) subquery->targetList))
746 747 748 749
		return false;

	/*
	 * Hack: don't try to pull up a subquery with an empty jointree.
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Bruce Momjian 已提交
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	 * query_planner() will correctly generate a Result plan for a jointree
	 * that's totally empty, but I don't think the right things happen if an
	 * empty FromExpr appears lower down in a jointree. Not worth working hard
	 * on this, just to collapse SubqueryScan/Result into Result...
754 755 756 757 758 759 760
	 */
	if (subquery->jointree->fromlist == NIL)
		return false;

	return true;
}

761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793
/*
 * is_simple_union_all
 *	  Check a subquery to see if it's a simple UNION ALL.
 *
 * We require all the setops to be UNION ALL (no mixing) and there can't be
 * any datatype coercions involved, ie, all the leaf queries must emit the
 * same datatypes.
 */
static bool
is_simple_union_all(Query *subquery)
{
	SetOperationStmt *topop;

	/* Let's just make sure it's a valid subselect ... */
	if (!IsA(subquery, Query) ||
		subquery->commandType != CMD_SELECT ||
		subquery->utilityStmt != NULL ||
		subquery->intoClause != NULL)
		elog(ERROR, "subquery is bogus");

	/* Is it a set-operation query at all? */
	topop = (SetOperationStmt *) subquery->setOperations;
	if (!topop)
		return false;
	Assert(IsA(topop, SetOperationStmt));

	/* Can't handle ORDER BY, LIMIT/OFFSET, locking, or WITH */
	if (subquery->sortClause ||
		subquery->limitOffset ||
		subquery->limitCount ||
		subquery->rowMarks ||
		subquery->cteList)
		return false;
794

795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833
	/* Recursively check the tree of set operations */
	return is_simple_union_all_recurse((Node *) topop, subquery,
									   topop->colTypes);
}

static bool
is_simple_union_all_recurse(Node *setOp, Query *setOpQuery, List *colTypes)
{
	if (IsA(setOp, RangeTblRef))
	{
		RangeTblRef *rtr = (RangeTblRef *) setOp;
		RangeTblEntry *rte = rt_fetch(rtr->rtindex, setOpQuery->rtable);
		Query	   *subquery = rte->subquery;

		Assert(subquery != NULL);

		/* Leaf nodes are OK if they match the toplevel column types */
		/* We don't have to compare typmods here */
		return tlist_same_datatypes(subquery->targetList, colTypes, true);
	}
	else if (IsA(setOp, SetOperationStmt))
	{
		SetOperationStmt *op = (SetOperationStmt *) setOp;

		/* Must be UNION ALL */
		if (op->op != SETOP_UNION || !op->all)
			return false;

		/* Recurse to check inputs */
		return is_simple_union_all_recurse(op->larg, setOpQuery, colTypes) &&
			is_simple_union_all_recurse(op->rarg, setOpQuery, colTypes);
	}
	else
	{
		elog(ERROR, "unrecognized node type: %d",
			 (int) nodeTag(setOp));
		return false;			/* keep compiler quiet */
	}
}
834

835 836 837
/*
 * has_nullable_targetlist
 *	  Check a subquery in the range table to see if all the non-junk
838 839 840
 *	  targetlist items are simple variables or strict functions of simple
 *	  variables (and, hence, will correctly go to NULL when examined above
 *	  the point of an outer join).
841
 *
842 843 844
 * NOTE: it would be correct (and useful) to ignore output columns that aren't
 * actually referenced by the enclosing query ... but we do not have that
 * information available at this point.
845 846 847 848
 */
static bool
has_nullable_targetlist(Query *subquery)
{
849
	ListCell   *l;
850 851 852 853 854 855

	foreach(l, subquery->targetList)
	{
		TargetEntry *tle = (TargetEntry *) lfirst(l);

		/* ignore resjunk columns */
856
		if (tle->resjunk)
857 858
			continue;

859 860 861
		/* Must contain a Var of current level */
		if (!contain_vars_of_level((Node *) tle->expr, 0))
			return false;
862

863 864 865 866 867
		/* Must not contain any non-strict constructs */
		if (contain_nonstrict_functions((Node *) tle->expr))
			return false;

		/* This one's OK, keep scanning */
868 869 870 871
	}
	return true;
}

872 873 874 875 876 877 878 879 880 881 882 883
/*
 * is_safe_append_member
 *	  Check a subquery that is a leaf of a UNION ALL appendrel to see if it's
 *	  safe to pull up.
 */
static bool
is_safe_append_member(Query *subquery)
{
	FromExpr   *jtnode;
	ListCell   *l;

	/*
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Bruce Momjian 已提交
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	 * It's only safe to pull up the child if its jointree contains exactly
	 * one RTE, else the AppendRelInfo data structure breaks. The one base RTE
	 * could be buried in several levels of FromExpr, however.
887
	 *
B
Bruce Momjian 已提交
888 889 890 891 892
	 * Also, the child can't have any WHERE quals because there's no place to
	 * put them in an appendrel.  (This is a bit annoying...) If we didn't
	 * need to check this, we'd just test whether get_relids_in_jointree()
	 * yields a singleton set, to be more consistent with the coding of
	 * fix_append_rel_relids().
893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908
	 */
	jtnode = subquery->jointree;
	while (IsA(jtnode, FromExpr))
	{
		if (jtnode->quals != NULL)
			return false;
		if (list_length(jtnode->fromlist) != 1)
			return false;
		jtnode = linitial(jtnode->fromlist);
	}
	if (!IsA(jtnode, RangeTblRef))
		return false;

	/*
	 * XXX For the moment we also have to insist that the subquery's tlist
	 * includes only simple Vars.  This is pretty annoying, but fixing it
B
Bruce Momjian 已提交
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	 * seems to require nontrivial changes --- mainly because joinrel tlists
	 * are presently assumed to contain only Vars.	Perhaps a pseudo-variable
	 * mechanism similar to the one speculated about in pull_up_subqueries'
	 * comments would help?  FIXME someday.
913 914 915 916 917 918 919 920 921 922 923 924 925 926
	 */
	foreach(l, subquery->targetList)
	{
		TargetEntry *tle = (TargetEntry *) lfirst(l);

		if (tle->resjunk)
			continue;
		if (!(tle->expr && IsA(tle->expr, Var)))
			return false;
	}

	return true;
}

927 928 929 930 931 932
/*
 * Helper routine for pull_up_subqueries: do ResolveNew on every expression
 * in the jointree, without changing the jointree structure itself.  Ugly,
 * but there's no other way...
 */
static void
933
resolvenew_in_jointree(Node *jtnode, int varno,
934
					   RangeTblEntry *rte, List *subtlist)
935
{
936 937
	ListCell   *l;

938 939 940 941 942 943 944 945 946 947 948
	if (jtnode == NULL)
		return;
	if (IsA(jtnode, RangeTblRef))
	{
		/* nothing to do here */
	}
	else if (IsA(jtnode, FromExpr))
	{
		FromExpr   *f = (FromExpr *) jtnode;

		foreach(l, f->fromlist)
949
			resolvenew_in_jointree(lfirst(l), varno, rte, subtlist);
950
		f->quals = ResolveNew(f->quals,
951
							  varno, 0, rte,
952
							  subtlist, CMD_SELECT, 0);
953 954 955 956 957
	}
	else if (IsA(jtnode, JoinExpr))
	{
		JoinExpr   *j = (JoinExpr *) jtnode;

958 959
		resolvenew_in_jointree(j->larg, varno, rte, subtlist);
		resolvenew_in_jointree(j->rarg, varno, rte, subtlist);
960 961
		foreach(l, j->subqfromlist)
			resolvenew_in_jointree(lfirst(l), varno, rte, subtlist);
962
		j->quals = ResolveNew(j->quals,
963
							  varno, 0, rte,
964
							  subtlist, CMD_SELECT, 0);
965 966

		/*
B
Bruce Momjian 已提交
967 968
		 * We don't bother to update the colvars list, since it won't be used
		 * again ...
969 970 971
		 */
	}
	else
972 973
		elog(ERROR, "unrecognized node type: %d",
			 (int) nodeTag(jtnode));
974 975 976
}

/*
977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999
 * reduce_outer_joins
 *		Attempt to reduce outer joins to plain inner joins.
 *
 * The idea here is that given a query like
 *		SELECT ... FROM a LEFT JOIN b ON (...) WHERE b.y = 42;
 * we can reduce the LEFT JOIN to a plain JOIN if the "=" operator in WHERE
 * is strict.  The strict operator will always return NULL, causing the outer
 * WHERE to fail, on any row where the LEFT JOIN filled in NULLs for b's
 * columns.  Therefore, there's no need for the join to produce null-extended
 * rows in the first place --- which makes it a plain join not an outer join.
 * (This scenario may not be very likely in a query written out by hand, but
 * it's reasonably likely when pushing quals down into complex views.)
 *
 * More generally, an outer join can be reduced in strength if there is a
 * strict qual above it in the qual tree that constrains a Var from the
 * nullable side of the join to be non-null.  (For FULL joins this applies
 * to each side separately.)
 *
 * To ease recognition of strict qual clauses, we require this routine to be
 * run after expression preprocessing (i.e., qual canonicalization and JOIN
 * alias-var expansion).
 */
void
1000
reduce_outer_joins(PlannerInfo *root)
1001 1002 1003 1004
{
	reduce_outer_joins_state *state;

	/*
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Bruce Momjian 已提交
1005 1006 1007 1008 1009 1010 1011
	 * To avoid doing strictness checks on more quals than necessary, we want
	 * to stop descending the jointree as soon as there are no outer joins
	 * below our current point.  This consideration forces a two-pass process.
	 * The first pass gathers information about which base rels appear below
	 * each side of each join clause, and about whether there are outer
	 * join(s) below each side of each join clause. The second pass examines
	 * qual clauses and changes join types as it descends the tree.
1012
	 */
1013
	state = reduce_outer_joins_pass1((Node *) root->parse->jointree);
1014 1015 1016

	/* planner.c shouldn't have called me if no outer joins */
	if (state == NULL || !state->contains_outer)
1017
		elog(ERROR, "so where are the outer joins?");
1018

1019 1020
	reduce_outer_joins_pass2((Node *) root->parse->jointree,
							 state, root, NULL);
1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031
}

/*
 * reduce_outer_joins_pass1 - phase 1 data collection
 *
 * Returns a state node describing the given jointree node.
 */
static reduce_outer_joins_state *
reduce_outer_joins_pass1(Node *jtnode)
{
	reduce_outer_joins_state *result;
1032
	ListCell   *l;
1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082

	result = (reduce_outer_joins_state *)
		palloc(sizeof(reduce_outer_joins_state));
	result->relids = NULL;
	result->contains_outer = false;
	result->sub_states = NIL;

	if (jtnode == NULL)
		return result;
	if (IsA(jtnode, RangeTblRef))
	{
		int			varno = ((RangeTblRef *) jtnode)->rtindex;

		result->relids = bms_make_singleton(varno);
	}
	else if (IsA(jtnode, FromExpr))
	{
		FromExpr   *f = (FromExpr *) jtnode;

		foreach(l, f->fromlist)
		{
			reduce_outer_joins_state *sub_state;

			sub_state = reduce_outer_joins_pass1(lfirst(l));
			result->relids = bms_add_members(result->relids,
											 sub_state->relids);
			result->contains_outer |= sub_state->contains_outer;
			result->sub_states = lappend(result->sub_states, sub_state);
		}
	}
	else if (IsA(jtnode, JoinExpr))
	{
		JoinExpr   *j = (JoinExpr *) jtnode;
		reduce_outer_joins_state *sub_state;

		/* join's own RT index is not wanted in result->relids */
		if (IS_OUTER_JOIN(j->jointype))
			result->contains_outer = true;

		sub_state = reduce_outer_joins_pass1(j->larg);
		result->relids = bms_add_members(result->relids,
										 sub_state->relids);
		result->contains_outer |= sub_state->contains_outer;
		result->sub_states = lappend(result->sub_states, sub_state);

		sub_state = reduce_outer_joins_pass1(j->rarg);
		result->relids = bms_add_members(result->relids,
										 sub_state->relids);
		result->contains_outer |= sub_state->contains_outer;
		result->sub_states = lappend(result->sub_states, sub_state);
1083 1084 1085 1086 1087 1088 1089 1090 1091

		foreach(l, j->subqfromlist)
		{
			sub_state = reduce_outer_joins_pass1(lfirst(l));
			result->relids = bms_add_members(result->relids,
											 sub_state->relids);
			result->contains_outer |= sub_state->contains_outer;
			result->sub_states = lappend(result->sub_states, sub_state);
		}
1092 1093
	}
	else
1094 1095
		elog(ERROR, "unrecognized node type: %d",
			 (int) nodeTag(jtnode));
1096 1097 1098 1099 1100 1101 1102 1103
	return result;
}

/*
 * reduce_outer_joins_pass2 - phase 2 processing
 *
 *	jtnode: current jointree node
 *	state: state data collected by phase 1 for this node
1104
 *	root: toplevel planner state
1105 1106 1107 1108
 *	nonnullable_rels: set of base relids forced non-null by upper quals
 */
static void
reduce_outer_joins_pass2(Node *jtnode,
1109
						 reduce_outer_joins_state *state,
1110
						 PlannerInfo *root,
1111 1112
						 Relids nonnullable_rels)
{
1113 1114 1115
	ListCell   *l;
	ListCell   *s;

1116 1117 1118 1119 1120
	/*
	 * pass 2 should never descend as far as an empty subnode or base rel,
	 * because it's only called on subtrees marked as contains_outer.
	 */
	if (jtnode == NULL)
1121
		elog(ERROR, "reached empty jointree");
1122
	if (IsA(jtnode, RangeTblRef))
1123
		elog(ERROR, "reached base rel");
1124 1125 1126 1127 1128 1129
	else if (IsA(jtnode, FromExpr))
	{
		FromExpr   *f = (FromExpr *) jtnode;
		Relids		pass_nonnullable;

		/* Scan quals to see if we can add any nonnullability constraints */
1130
		pass_nonnullable = find_nonnullable_rels(f->quals);
1131 1132 1133
		pass_nonnullable = bms_add_members(pass_nonnullable,
										   nonnullable_rels);
		/* And recurse --- but only into interesting subtrees */
1134
		Assert(list_length(f->fromlist) == list_length(state->sub_states));
1135
		forboth(l, f->fromlist, s, state->sub_states)
1136 1137 1138 1139
		{
			reduce_outer_joins_state *sub_state = lfirst(s);

			if (sub_state->contains_outer)
1140
				reduce_outer_joins_pass2(lfirst(l), sub_state, root,
1141 1142 1143 1144 1145 1146 1147 1148 1149
										 pass_nonnullable);
		}
		bms_free(pass_nonnullable);
	}
	else if (IsA(jtnode, JoinExpr))
	{
		JoinExpr   *j = (JoinExpr *) jtnode;
		int			rtindex = j->rtindex;
		JoinType	jointype = j->jointype;
1150
		reduce_outer_joins_state *left_state = linitial(state->sub_states);
1151
		reduce_outer_joins_state *right_state = lsecond(state->sub_states);
1152
		reduce_outer_joins_state *sub_state;
1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184

		/* Can we simplify this join? */
		switch (jointype)
		{
			case JOIN_LEFT:
				if (bms_overlap(nonnullable_rels, right_state->relids))
					jointype = JOIN_INNER;
				break;
			case JOIN_RIGHT:
				if (bms_overlap(nonnullable_rels, left_state->relids))
					jointype = JOIN_INNER;
				break;
			case JOIN_FULL:
				if (bms_overlap(nonnullable_rels, left_state->relids))
				{
					if (bms_overlap(nonnullable_rels, right_state->relids))
						jointype = JOIN_INNER;
					else
						jointype = JOIN_LEFT;
				}
				else
				{
					if (bms_overlap(nonnullable_rels, right_state->relids))
						jointype = JOIN_RIGHT;
				}
				break;
			default:
				break;
		}
		if (jointype != j->jointype)
		{
			/* apply the change to both jointree node and RTE */
1185
			RangeTblEntry *rte = rt_fetch(rtindex, root->parse->rtable);
1186 1187 1188 1189 1190 1191 1192

			Assert(rte->rtekind == RTE_JOIN);
			Assert(rte->jointype == j->jointype);
			rte->jointype = j->jointype = jointype;
		}

		/* Only recurse if there's more to do below here */
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        foreach(l, state->sub_states)
        {
            sub_state = (reduce_outer_joins_state *)lfirst(l);
            if (sub_state->contains_outer)
                break;
        }
		if (l)
1200
		{
1201
			Relids		local_nonnullable;
1202 1203 1204
			Relids		pass_nonnullable;

			/*
1205
			 * If this join is (now) inner, we can add any nonnullability
B
Bruce Momjian 已提交
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			 * constraints its quals provide to those we got from above. But
			 * if it is outer, we can only pass down the local constraints
			 * into the nullable side, because an outer join never eliminates
			 * any rows from its non-nullable side.  If it's a FULL join then
			 * it doesn't eliminate anything from either side.
1211
			 */
1212 1213
			if (jointype != JOIN_FULL)
			{
1214
				local_nonnullable = find_nonnullable_rels(j->quals);
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				local_nonnullable = bms_add_members(local_nonnullable,
													nonnullable_rels);
			}
			else
B
Bruce Momjian 已提交
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				local_nonnullable = NULL;		/* no use in calculating it */
1220

1221
			if (left_state->contains_outer)
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			{
				if (jointype == JOIN_INNER || jointype == JOIN_RIGHT)
					pass_nonnullable = local_nonnullable;
				else
					pass_nonnullable = nonnullable_rels;
1227
				reduce_outer_joins_pass2(j->larg, left_state, root,
1228
										 pass_nonnullable);
1229
			}
1230
			if (right_state->contains_outer)
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			{
				if (jointype == JOIN_INNER || jointype == JOIN_LEFT)
					pass_nonnullable = local_nonnullable;
				else
					pass_nonnullable = nonnullable_rels;
1236
				reduce_outer_joins_pass2(j->rarg, right_state, root,
1237
										 pass_nonnullable);
1238
			}
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            /*
             * CDB: Simplify outer joins pulled up from flattened subqueries.
             * For a left or right outer join, the subqfromlist items belong
             * to the null-augmented side; so we pass local_nonnullable down
             * regardless of the jointype.  (For FULL JOIN, subqfromlist is
             * always empty.)
             */
            s = lnext(lnext(list_head(state->sub_states)));
            foreach(l, j->subqfromlist)
            {
                sub_state = (reduce_outer_joins_state *)lfirst(s);
                if (sub_state->contains_outer)
				    reduce_outer_joins_pass2(lfirst(l), sub_state, root,
										     local_nonnullable);
                s = lnext(s);
            }

1257
			bms_free(local_nonnullable);
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		}
	}
	else
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		elog(ERROR, "unrecognized node type: %d",
			 (int) nodeTag(jtnode));
1263 1264
}

1265
/*
1266
 * fix_in_clause_relids: update RT-index sets of InClauseInfo nodes
1267 1268
 *
 * When we pull up a subquery, any InClauseInfo references to the subquery's
1269
 * RT index have to be replaced by the set of substituted relids.
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 *
 * We assume we may modify the InClauseInfo nodes in-place.
 */
static void
fix_in_clause_relids(List *in_info_list, int varno, Relids subrelids)
{
1276
	ListCell   *l;
1277 1278 1279 1280 1281

	foreach(l, in_info_list)
	{
		InClauseInfo *ininfo = (InClauseInfo *) lfirst(l);

1282
		if (bms_is_member(varno, ininfo->righthand))
1283
		{
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			ininfo->righthand = bms_del_member(ininfo->righthand, varno);
			ininfo->righthand = bms_add_members(ininfo->righthand, subrelids);
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		}
	}
}

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/*
 * fix_append_rel_relids: update RT-index fields of AppendRelInfo nodes
 *
 * When we pull up a subquery, any AppendRelInfo references to the subquery's
 * RT index have to be replaced by the substituted relid (and there had better
 * be only one).
 *
 * We assume we may modify the AppendRelInfo nodes in-place.
 */
static void
1300
fix_append_rel_relids(List *append_rel_list, int varno, Relids subrelids)
1301 1302 1303 1304 1305 1306
{
	ListCell   *l;
	int			subvarno = -1;

	/*
	 * We only want to extract the member relid once, but we mustn't fail
B
Bruce Momjian 已提交
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	 * immediately if there are multiple members; it could be that none of the
	 * AppendRelInfo nodes refer to it.  So compute it on first use. Note that
	 * bms_singleton_member will complain if set is not singleton.
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	 */
	foreach(l, append_rel_list)
	{
		AppendRelInfo *appinfo = (AppendRelInfo *) lfirst(l);

		/* The parent_relid shouldn't ever be a pullup target */
		Assert(appinfo->parent_relid != varno);

		if (appinfo->child_relid == varno)
		{
			if (subvarno < 0)
				subvarno = bms_singleton_member(subrelids);
			appinfo->child_relid = subvarno;
		}
	}
}

1327
/*
1328
 * get_relids_in_jointree: get set of base RT indexes present in a jointree
1329
 */
1330
Relids
1331 1332
get_relids_in_jointree(Node *jtnode)
{
1333
	Relids		result = NULL;
1334
	ListCell   *l;
1335 1336 1337 1338 1339 1340 1341

	if (jtnode == NULL)
		return result;
	if (IsA(jtnode, RangeTblRef))
	{
		int			varno = ((RangeTblRef *) jtnode)->rtindex;

1342
		result = bms_make_singleton(varno);
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	}
	else if (IsA(jtnode, FromExpr))
	{
		FromExpr   *f = (FromExpr *) jtnode;

		foreach(l, f->fromlist)
		{
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			result = bms_join(result,
							  get_relids_in_jointree(lfirst(l)));
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		}
	}
	else if (IsA(jtnode, JoinExpr))
	{
		JoinExpr   *j = (JoinExpr *) jtnode;

		/* join's own RT index is not wanted in result */
		result = get_relids_in_jointree(j->larg);
1360
		result = bms_join(result, get_relids_in_jointree(j->rarg));
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		foreach(l, j->subqfromlist)
			result = bms_join(result, get_relids_in_jointree((Node *)lfirst(l)));
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	}
	else
1366 1367
		elog(ERROR, "unrecognized node type: %d",
			 (int) nodeTag(jtnode));
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	return result;
}

/*
1372
 * get_relids_for_join: get set of base RT indexes making up a join
1373
 */
1374
Relids
1375
get_relids_for_join(PlannerInfo *root, int joinrelid)
1376 1377 1378
{
	Node	   *jtnode;

1379 1380
	jtnode = find_jointree_node_for_rel((Node *) root->parse->jointree,
										joinrelid);
1381
	if (!jtnode)
1382
		elog(ERROR, "could not find join node %d", joinrelid);
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	return get_relids_in_jointree(jtnode);
}

/*
 * find_jointree_node_for_rel: locate jointree node for a base or join RT index
 *
 * Returns NULL if not found
 */
static Node *
find_jointree_node_for_rel(Node *jtnode, int relid)
{
1394 1395
	ListCell   *l;

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	if (jtnode == NULL)
		return NULL;
	if (IsA(jtnode, RangeTblRef))
	{
		int			varno = ((RangeTblRef *) jtnode)->rtindex;

		if (relid == varno)
			return jtnode;
	}
	else if (IsA(jtnode, FromExpr))
	{
		FromExpr   *f = (FromExpr *) jtnode;

		foreach(l, f->fromlist)
		{
			jtnode = find_jointree_node_for_rel(lfirst(l), relid);
			if (jtnode)
				return jtnode;
		}
	}
	else if (IsA(jtnode, JoinExpr))
	{
		JoinExpr   *j = (JoinExpr *) jtnode;

		if (relid == j->rtindex)
			return jtnode;
		jtnode = find_jointree_node_for_rel(j->larg, relid);
		if (jtnode)
			return jtnode;
		jtnode = find_jointree_node_for_rel(j->rarg, relid);
		if (jtnode)
			return jtnode;
1428 1429 1430 1431 1432 1433 1434

		foreach(l, j->subqfromlist)
		{
			jtnode = find_jointree_node_for_rel(lfirst(l), relid);
			if (jtnode)
				return jtnode;
		}
1435 1436
	}
	else
1437 1438
		elog(ERROR, "unrecognized node type: %d",
			 (int) nodeTag(jtnode));
1439 1440
	return NULL;
}
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/*
 * init_list_cteplaninfo
 *   Create a list of CtePlanInfos of size 'numCtes', and initialize each CtePlanInfo.
 */
List *
init_list_cteplaninfo(int numCtes)
{
	List *list_cteplaninfo = NULL;
	
	for (int cteNo = 0; cteNo < numCtes; cteNo++)
	{
		CtePlanInfo *ctePlanInfo = palloc0(sizeof(CtePlanInfo));
		list_cteplaninfo = lappend(list_cteplaninfo, ctePlanInfo);
	}

	return list_cteplaninfo;
	
}