initsplan.c File Reference

#include "postgres.h"
#include "catalog/pg_class.h"
#include "catalog/pg_type.h"
#include "nodes/makefuncs.h"
#include "nodes/nodeFuncs.h"
#include "optimizer/clauses.h"
#include "optimizer/cost.h"
#include "optimizer/inherit.h"
#include "optimizer/joininfo.h"
#include "optimizer/optimizer.h"
#include "optimizer/pathnode.h"
#include "optimizer/paths.h"
#include "optimizer/placeholder.h"
#include "optimizer/planmain.h"
#include "optimizer/planner.h"
#include "optimizer/prep.h"
#include "optimizer/restrictinfo.h"
#include "parser/analyze.h"
#include "rewrite/rewriteManip.h"
#include "utils/lsyscache.h"
#include "utils/typcache.h"

Include dependency graph for initsplan.c:

Go to the source code of this file.

Data Structures
struct	PostponedQual

Typedefs
typedef struct PostponedQual	PostponedQual

Functions
static void	extract_lateral_references (PlannerInfo *root, RelOptInfo *brel, Index rtindex)
static List *	deconstruct_recurse (PlannerInfo *root, Node *jtnode, bool below_outer_join, Relids *qualscope, Relids *inner_join_rels, List **postponed_qual_list)
static void	process_security_barrier_quals (PlannerInfo *root, int rti, Relids qualscope, bool below_outer_join)
static SpecialJoinInfo *	make_outerjoininfo (PlannerInfo *root, Relids left_rels, Relids right_rels, Relids inner_join_rels, JoinType jointype, List *clause)
static void	compute_semijoin_info (PlannerInfo *root, SpecialJoinInfo *sjinfo, List *clause)
static void	distribute_qual_to_rels (PlannerInfo *root, Node *clause, bool below_outer_join, JoinType jointype, Index security_level, Relids qualscope, Relids ojscope, Relids outerjoin_nonnullable, List **postponed_qual_list)
static bool	check_outerjoin_delay (PlannerInfo *root, Relids *relids_p, Relids *nullable_relids_p, bool is_pushed_down)
static bool	check_equivalence_delay (PlannerInfo *root, RestrictInfo *restrictinfo)
static bool	check_redundant_nullability_qual (PlannerInfo *root, Node *clause)
static void	check_mergejoinable (RestrictInfo *restrictinfo)
static void	check_hashjoinable (RestrictInfo *restrictinfo)
static void	check_memoizable (RestrictInfo *restrictinfo)
void	add_base_rels_to_query (PlannerInfo *root, Node *jtnode)
void	add_other_rels_to_query (PlannerInfo *root)
void	build_base_rel_tlists (PlannerInfo *root, List *final_tlist)
void	add_vars_to_targetlist (PlannerInfo *root, List *vars, Relids where_needed)
void	find_lateral_references (PlannerInfo *root)
void	create_lateral_join_info (PlannerInfo *root)
List *	deconstruct_jointree (PlannerInfo *root)
void	distribute_restrictinfo_to_rels (PlannerInfo *root, RestrictInfo *restrictinfo)
RestrictInfo *	process_implied_equality (PlannerInfo *root, Oid opno, Oid collation, Expr *item1, Expr *item2, Relids qualscope, Relids nullable_relids, Index security_level, bool below_outer_join, bool both_const)
RestrictInfo *	build_implied_join_equality (PlannerInfo *root, Oid opno, Oid collation, Expr *item1, Expr *item2, Relids qualscope, Relids nullable_relids, Index security_level)
void	match_foreign_keys_to_quals (PlannerInfo *root)

Variables
int	from_collapse_limit
int	join_collapse_limit

Typedef Documentation

PostponedQual

typedef struct PostponedQual PostponedQual

Function Documentation

add_base_rels_to_query()

void add_base_rels_to_query	(	PlannerInfo *	root,
		Node *	jtnode
	)

Definition at line 106 of file initsplan.c.

{
    if (jtnode == NULL)
        return;
    if (IsA(jtnode, RangeTblRef))
    {
        int         varno = ((RangeTblRef *) jtnode)->rtindex;
 
        (void) build_simple_rel(root, varno, NULL);
    }
    else if (IsA(jtnode, FromExpr))
    {
        FromExpr   *f = (FromExpr *) jtnode;
        ListCell   *l;
 
        foreach(l, f->fromlist)
            add_base_rels_to_query(root, lfirst(l));
    }
    else if (IsA(jtnode, JoinExpr))
    {
        JoinExpr   *j = (JoinExpr *) jtnode;
 
        add_base_rels_to_query(root, j->larg);
        add_base_rels_to_query(root, j->rarg);
    }
    else
        elog(ERROR, "unrecognized node type: %d",
             (int) nodeTag(jtnode));
}

References build_simple_rel(), elog(), ERROR, FromExpr::fromlist, IsA, j, lfirst, and nodeTag.

Referenced by query_planner().

add_other_rels_to_query()

void add_other_rels_to_query

(

PlannerInfo *

root

)

Definition at line 144 of file initsplan.c.

{
    int         rti;
 
    for (rti = 1; rti < root->simple_rel_array_size; rti++)
    {
        RelOptInfo *rel = root->simple_rel_array[rti];
        RangeTblEntry *rte = root->simple_rte_array[rti];
 
        /* there may be empty slots corresponding to non-baserel RTEs */
        if (rel == NULL)
            continue;
 
        /* Ignore any "otherrels" that were already added. */
        if (rel->reloptkind != RELOPT_BASEREL)
            continue;
 
        /* If it's marked as inheritable, look for children. */
        if (rte->inh)
            expand_inherited_rtentry(root, rel, rte, rti);
    }
}

References expand_inherited_rtentry(), RangeTblEntry::inh, RELOPT_BASEREL, RelOptInfo::reloptkind, and PlannerInfo::simple_rel_array_size.

Referenced by query_planner().

add_vars_to_targetlist()

void add_vars_to_targetlist	(	PlannerInfo *	root,
		List *	vars,
		Relids	where_needed
	)

Definition at line 228 of file initsplan.c.

{
    ListCell   *temp;
 
    Assert(!bms_is_empty(where_needed));
 
    foreach(temp, vars)
    {
        Node       *node = (Node *) lfirst(temp);
 
        if (IsA(node, Var))
        {
            Var        *var = (Var *) node;
            RelOptInfo *rel = find_base_rel(root, var->varno);
            int         attno = var->varattno;
 
            if (bms_is_subset(where_needed, rel->relids))
                continue;
            Assert(attno >= rel->min_attr && attno <= rel->max_attr);
            attno -= rel->min_attr;
            if (rel->attr_needed[attno] == NULL)
            {
                /* Variable not yet requested, so add to rel's targetlist */
                /* XXX is copyObject necessary here? */
                rel->reltarget->exprs = lappend(rel->reltarget->exprs,
                                                copyObject(var));
                /* reltarget cost and width will be computed later */
            }
            rel->attr_needed[attno] = bms_add_members(rel->attr_needed[attno],
                                                      where_needed);
        }
        else if (IsA(node, PlaceHolderVar))
        {
            PlaceHolderVar *phv = (PlaceHolderVar *) node;
            PlaceHolderInfo *phinfo = find_placeholder_info(root, phv);
 
            phinfo->ph_needed = bms_add_members(phinfo->ph_needed,
                                                where_needed);
        }
        else
            elog(ERROR, "unrecognized node type: %d", (int) nodeTag(node));
    }
}

References Assert(), bms_add_members(), bms_is_empty(), bms_is_subset(), copyObject, elog(), ERROR, PathTarget::exprs, find_base_rel(), find_placeholder_info(), IsA, lappend(), lfirst, RelOptInfo::min_attr, nodeTag, PlaceHolderInfo::ph_needed, RelOptInfo::relids, RelOptInfo::reltarget, Var::varattno, and Var::varno.

Referenced by build_base_rel_tlists(), distribute_qual_to_rels(), expand_inherited_rtentry(), extract_lateral_references(), fix_placeholder_input_needed_levels(), generate_base_implied_equalities_no_const(), and process_implied_equality().

build_base_rel_tlists()

void build_base_rel_tlists	(	PlannerInfo *	root,
		List *	final_tlist
	)

Definition at line 183 of file initsplan.c.

{
    List       *tlist_vars = pull_var_clause((Node *) final_tlist,
                                             PVC_RECURSE_AGGREGATES |
                                             PVC_RECURSE_WINDOWFUNCS |
                                             PVC_INCLUDE_PLACEHOLDERS);
 
    if (tlist_vars != NIL)
    {
        add_vars_to_targetlist(root, tlist_vars, bms_make_singleton(0));
        list_free(tlist_vars);
    }
 
    /*
     * If there's a HAVING clause, we'll need the Vars it uses, too.  Note
     * that HAVING can contain Aggrefs but not WindowFuncs.
     */
    if (root->parse->havingQual)
    {
        List       *having_vars = pull_var_clause(root->parse->havingQual,
                                                  PVC_RECURSE_AGGREGATES |
                                                  PVC_INCLUDE_PLACEHOLDERS);
 
        if (having_vars != NIL)
        {
            add_vars_to_targetlist(root, having_vars,
                                   bms_make_singleton(0));
            list_free(having_vars);
        }
    }
}

References add_vars_to_targetlist(), bms_make_singleton(), Query::havingQual, list_free(), NIL, PlannerInfo::parse, pull_var_clause(), PVC_INCLUDE_PLACEHOLDERS, PVC_RECURSE_AGGREGATES, and PVC_RECURSE_WINDOWFUNCS.

Referenced by query_planner().

build_implied_join_equality()

RestrictInfo* build_implied_join_equality	(	PlannerInfo *	root,
		Oid	opno,
		Oid	collation,
		Expr *	item1,
		Expr *	item2,
		Relids	qualscope,
		Relids	nullable_relids,
		Index	security_level
	)

Definition at line 2426 of file initsplan.c.

{
    RestrictInfo *restrictinfo;
    Expr       *clause;
 
    /*
     * Build the new clause.  Copy to ensure it shares no substructure with
     * original (this is necessary in case there are subselects in there...)
     */
    clause = make_opclause(opno,
                           BOOLOID, /* opresulttype */
                           false,   /* opretset */
                           copyObject(item1),
                           copyObject(item2),
                           InvalidOid,
                           collation);
 
    /*
     * Build the RestrictInfo node itself.
     */
    restrictinfo = make_restrictinfo(root,
                                     clause,
                                     true,  /* is_pushed_down */
                                     false, /* outerjoin_delayed */
                                     false, /* pseudoconstant */
                                     security_level,    /* security_level */
                                     qualscope, /* required_relids */
                                     NULL,  /* outer_relids */
                                     nullable_relids);  /* nullable_relids */
 
    /* Set mergejoinability/hashjoinability flags */
    check_mergejoinable(restrictinfo);
    check_hashjoinable(restrictinfo);
    check_memoizable(restrictinfo);
 
    return restrictinfo;
}

References check_hashjoinable(), check_memoizable(), check_mergejoinable(), copyObject, InvalidOid, make_opclause(), and make_restrictinfo().

Referenced by create_join_clause(), reconsider_full_join_clause(), and reconsider_outer_join_clause().

check_equivalence_delay()

static bool check_equivalence_delay ( PlannerInfo *  root, RestrictInfo *  restrictinfo  )

static

Definition at line 2108 of file initsplan.c.

{
    Relids      relids;
    Relids      nullable_relids;
 
    /* fast path if no special joins */
    if (root->join_info_list == NIL)
        return true;
 
    /* must copy restrictinfo's relids to avoid changing it */
    relids = bms_copy(restrictinfo->left_relids);
    /* check left side does not need delay */
    if (check_outerjoin_delay(root, &relids, &nullable_relids, true))
        return false;
 
    /* and similarly for the right side */
    relids = bms_copy(restrictinfo->right_relids);
    if (check_outerjoin_delay(root, &relids, &nullable_relids, true))
        return false;
 
    return true;
}

References bms_copy(), check_outerjoin_delay(), PlannerInfo::join_info_list, and NIL.

Referenced by distribute_qual_to_rels().

check_hashjoinable()

static void check_hashjoinable ( RestrictInfo *  restrictinfo )

static

Definition at line 2694 of file initsplan.c.

{
    Expr       *clause = restrictinfo->clause;
    Oid         opno;
    Node       *leftarg;
 
    if (restrictinfo->pseudoconstant)
        return;
    if (!is_opclause(clause))
        return;
    if (list_length(((OpExpr *) clause)->args) != 2)
        return;
 
    opno = ((OpExpr *) clause)->opno;
    leftarg = linitial(((OpExpr *) clause)->args);
 
    if (op_hashjoinable(opno, exprType(leftarg)) &&
        !contain_volatile_functions((Node *) restrictinfo))
        restrictinfo->hashjoinoperator = opno;
}

References generate_unaccent_rules::args, RestrictInfo::clause, contain_volatile_functions(), exprType(), is_opclause(), linitial, list_length(), and op_hashjoinable().

Referenced by build_implied_join_equality(), and distribute_restrictinfo_to_rels().

check_memoizable()

static void check_memoizable ( RestrictInfo *  restrictinfo )

static

Definition at line 2722 of file initsplan.c.

{
    TypeCacheEntry *typentry;
    Expr       *clause = restrictinfo->clause;
    Oid         lefttype;
    Oid         righttype;
 
    if (restrictinfo->pseudoconstant)
        return;
    if (!is_opclause(clause))
        return;
    if (list_length(((OpExpr *) clause)->args) != 2)
        return;
 
    lefttype = exprType(linitial(((OpExpr *) clause)->args));
 
    typentry = lookup_type_cache(lefttype, TYPECACHE_HASH_PROC |
                                 TYPECACHE_EQ_OPR);
 
    if (OidIsValid(typentry->hash_proc) && OidIsValid(typentry->eq_opr))
        restrictinfo->left_hasheqoperator = typentry->eq_opr;
 
    righttype = exprType(lsecond(((OpExpr *) clause)->args));
 
    /*
     * Lookup the right type, unless it's the same as the left type, in which
     * case typentry is already pointing to the required TypeCacheEntry.
     */
    if (lefttype != righttype)
        typentry = lookup_type_cache(righttype, TYPECACHE_HASH_PROC |
                                     TYPECACHE_EQ_OPR);
 
    if (OidIsValid(typentry->hash_proc) && OidIsValid(typentry->eq_opr))
        restrictinfo->right_hasheqoperator = typentry->eq_opr;
}

References generate_unaccent_rules::args, RestrictInfo::clause, TypeCacheEntry::eq_opr, exprType(), TypeCacheEntry::hash_proc, is_opclause(), linitial, list_length(), lookup_type_cache(), lsecond, OidIsValid, TYPECACHE_EQ_OPR, and TYPECACHE_HASH_PROC.

Referenced by build_implied_join_equality(), and distribute_restrictinfo_to_rels().

check_mergejoinable()

static void check_mergejoinable ( RestrictInfo *  restrictinfo )

static

Definition at line 2657 of file initsplan.c.

{
    Expr       *clause = restrictinfo->clause;
    Oid         opno;
    Node       *leftarg;
 
    if (restrictinfo->pseudoconstant)
        return;
    if (!is_opclause(clause))
        return;
    if (list_length(((OpExpr *) clause)->args) != 2)
        return;
 
    opno = ((OpExpr *) clause)->opno;
    leftarg = linitial(((OpExpr *) clause)->args);
 
    if (op_mergejoinable(opno, exprType(leftarg)) &&
        !contain_volatile_functions((Node *) restrictinfo))
        restrictinfo->mergeopfamilies = get_mergejoin_opfamilies(opno);
 
    /*
     * Note: op_mergejoinable is just a hint; if we fail to find the operator
     * in any btree opfamilies, mergeopfamilies remains NIL and so the clause
     * is not treated as mergejoinable.
     */
}

References generate_unaccent_rules::args, RestrictInfo::clause, contain_volatile_functions(), exprType(), get_mergejoin_opfamilies(), is_opclause(), linitial, list_length(), and op_mergejoinable().

Referenced by build_implied_join_equality(), distribute_qual_to_rels(), and process_implied_equality().

check_outerjoin_delay()

static bool check_outerjoin_delay ( PlannerInfo *  root, Relids *  relids_p, Relids *  nullable_relids_p, bool  is_pushed_down  )

static

Definition at line 2024 of file initsplan.c.

{
    Relids      relids;
    Relids      nullable_relids;
    bool        outerjoin_delayed;
    bool        found_some;
 
    /* fast path if no special joins */
    if (root->join_info_list == NIL)
    {
        *nullable_relids_p = NULL;
        return false;
    }
 
    /* must copy relids because we need the original value at the end */
    relids = bms_copy(*relids_p);
    nullable_relids = NULL;
    outerjoin_delayed = false;
    do
    {
        ListCell   *l;
 
        found_some = false;
        foreach(l, root->join_info_list)
        {
            SpecialJoinInfo *sjinfo = (SpecialJoinInfo *) lfirst(l);
 
            /* do we reference any nullable rels of this OJ? */
            if (bms_overlap(relids, sjinfo->min_righthand) ||
                (sjinfo->jointype == JOIN_FULL &&
                 bms_overlap(relids, sjinfo->min_lefthand)))
            {
                /* yes; have we included all its rels in relids? */
                if (!bms_is_subset(sjinfo->min_lefthand, relids) ||
                    !bms_is_subset(sjinfo->min_righthand, relids))
                {
                    /* no, so add them in */
                    relids = bms_add_members(relids, sjinfo->min_lefthand);
                    relids = bms_add_members(relids, sjinfo->min_righthand);
                    outerjoin_delayed = true;
                    /* we'll need another iteration */
                    found_some = true;
                }
                /* track all the nullable rels of relevant OJs */
                nullable_relids = bms_add_members(nullable_relids,
                                                  sjinfo->min_righthand);
                if (sjinfo->jointype == JOIN_FULL)
                    nullable_relids = bms_add_members(nullable_relids,
                                                      sjinfo->min_lefthand);
                /* set delay_upper_joins if needed */
                if (is_pushed_down && sjinfo->jointype != JOIN_FULL &&
                    bms_overlap(relids, sjinfo->min_lefthand))
                    sjinfo->delay_upper_joins = true;
            }
        }
    } while (found_some);
 
    /* identify just the actually-referenced nullable rels */
    nullable_relids = bms_int_members(nullable_relids, *relids_p);
 
    /* replace *relids_p, and return nullable_relids */
    bms_free(*relids_p);
    *relids_p = relids;
    *nullable_relids_p = nullable_relids;
    return outerjoin_delayed;
}

References bms_add_members(), bms_copy(), bms_free(), bms_int_members(), bms_is_subset(), bms_overlap(), SpecialJoinInfo::delay_upper_joins, JOIN_FULL, PlannerInfo::join_info_list, SpecialJoinInfo::jointype, lfirst, SpecialJoinInfo::min_lefthand, SpecialJoinInfo::min_righthand, and NIL.

Referenced by check_equivalence_delay(), and distribute_qual_to_rels().

check_redundant_nullability_qual()

static bool check_redundant_nullability_qual ( PlannerInfo *  root, Node *  clause  )

static

Definition at line 2143 of file initsplan.c.

{
    Var        *forced_null_var;
    Index       forced_null_rel;
    ListCell   *lc;
 
    /* Check for IS NULL, and identify the Var forced to NULL */
    forced_null_var = find_forced_null_var(clause);
    if (forced_null_var == NULL)
        return false;
    forced_null_rel = forced_null_var->varno;
 
    /*
     * If the Var comes from the nullable side of a lower antijoin, the IS
     * NULL condition is necessarily true.
     */
    foreach(lc, root->join_info_list)
    {
        SpecialJoinInfo *sjinfo = (SpecialJoinInfo *) lfirst(lc);
 
        if (sjinfo->jointype == JOIN_ANTI &&
            bms_is_member(forced_null_rel, sjinfo->syn_righthand))
            return true;
    }
 
    return false;
}

References bms_is_member(), find_forced_null_var(), JOIN_ANTI, PlannerInfo::join_info_list, SpecialJoinInfo::jointype, lfirst, SpecialJoinInfo::syn_righthand, and Var::varno.

Referenced by distribute_qual_to_rels().

compute_semijoin_info()

static void compute_semijoin_info ( PlannerInfo *  root, SpecialJoinInfo *  sjinfo, List *  clause  )

static

Definition at line 1400 of file initsplan.c.

{
    List       *semi_operators;
    List       *semi_rhs_exprs;
    bool        all_btree;
    bool        all_hash;
    ListCell   *lc;
 
    /* Initialize semijoin-related fields in case we can't unique-ify */
    sjinfo->semi_can_btree = false;
    sjinfo->semi_can_hash = false;
    sjinfo->semi_operators = NIL;
    sjinfo->semi_rhs_exprs = NIL;
 
    /* Nothing more to do if it's not a semijoin */
    if (sjinfo->jointype != JOIN_SEMI)
        return;
 
    /*
     * Look to see whether the semijoin's join quals consist of AND'ed
     * equality operators, with (only) RHS variables on only one side of each
     * one.  If so, we can figure out how to enforce uniqueness for the RHS.
     *
     * Note that the input clause list is the list of quals that are
     * *syntactically* associated with the semijoin, which in practice means
     * the synthesized comparison list for an IN or the WHERE of an EXISTS.
     * Particularly in the latter case, it might contain clauses that aren't
     * *semantically* associated with the join, but refer to just one side or
     * the other.  We can ignore such clauses here, as they will just drop
     * down to be processed within one side or the other.  (It is okay to
     * consider only the syntactically-associated clauses here because for a
     * semijoin, no higher-level quals could refer to the RHS, and so there
     * can be no other quals that are semantically associated with this join.
     * We do things this way because it is useful to have the set of potential
     * unique-ification expressions before we can extract the list of quals
     * that are actually semantically associated with the particular join.)
     *
     * Note that the semi_operators list consists of the joinqual operators
     * themselves (but commuted if needed to put the RHS value on the right).
     * These could be cross-type operators, in which case the operator
     * actually needed for uniqueness is a related single-type operator. We
     * assume here that that operator will be available from the btree or hash
     * opclass when the time comes ... if not, create_unique_plan() will fail.
     */
    semi_operators = NIL;
    semi_rhs_exprs = NIL;
    all_btree = true;
    all_hash = enable_hashagg;  /* don't consider hash if not enabled */
    foreach(lc, clause)
    {
        OpExpr     *op = (OpExpr *) lfirst(lc);
        Oid         opno;
        Node       *left_expr;
        Node       *right_expr;
        Relids      left_varnos;
        Relids      right_varnos;
        Relids      all_varnos;
        Oid         opinputtype;
 
        /* Is it a binary opclause? */
        if (!IsA(op, OpExpr) ||
            list_length(op->args) != 2)
        {
            /* No, but does it reference both sides? */
            all_varnos = pull_varnos(root, (Node *) op);
            if (!bms_overlap(all_varnos, sjinfo->syn_righthand) ||
                bms_is_subset(all_varnos, sjinfo->syn_righthand))
            {
                /*
                 * Clause refers to only one rel, so ignore it --- unless it
                 * contains volatile functions, in which case we'd better
                 * punt.
                 */
                if (contain_volatile_functions((Node *) op))
                    return;
                continue;
            }
            /* Non-operator clause referencing both sides, must punt */
            return;
        }
 
        /* Extract data from binary opclause */
        opno = op->opno;
        left_expr = linitial(op->args);
        right_expr = lsecond(op->args);
        left_varnos = pull_varnos(root, left_expr);
        right_varnos = pull_varnos(root, right_expr);
        all_varnos = bms_union(left_varnos, right_varnos);
        opinputtype = exprType(left_expr);
 
        /* Does it reference both sides? */
        if (!bms_overlap(all_varnos, sjinfo->syn_righthand) ||
            bms_is_subset(all_varnos, sjinfo->syn_righthand))
        {
            /*
             * Clause refers to only one rel, so ignore it --- unless it
             * contains volatile functions, in which case we'd better punt.
             */
            if (contain_volatile_functions((Node *) op))
                return;
            continue;
        }
 
        /* check rel membership of arguments */
        if (!bms_is_empty(right_varnos) &&
            bms_is_subset(right_varnos, sjinfo->syn_righthand) &&
            !bms_overlap(left_varnos, sjinfo->syn_righthand))
        {
            /* typical case, right_expr is RHS variable */
        }
        else if (!bms_is_empty(left_varnos) &&
                 bms_is_subset(left_varnos, sjinfo->syn_righthand) &&
                 !bms_overlap(right_varnos, sjinfo->syn_righthand))
        {
            /* flipped case, left_expr is RHS variable */
            opno = get_commutator(opno);
            if (!OidIsValid(opno))
                return;
            right_expr = left_expr;
        }
        else
        {
            /* mixed membership of args, punt */
            return;
        }
 
        /* all operators must be btree equality or hash equality */
        if (all_btree)
        {
            /* oprcanmerge is considered a hint... */
            if (!op_mergejoinable(opno, opinputtype) ||
                get_mergejoin_opfamilies(opno) == NIL)
                all_btree = false;
        }
        if (all_hash)
        {
            /* ... but oprcanhash had better be correct */
            if (!op_hashjoinable(opno, opinputtype))
                all_hash = false;
        }
        if (!(all_btree || all_hash))
            return;
 
        /* so far so good, keep building lists */
        semi_operators = lappend_oid(semi_operators, opno);
        semi_rhs_exprs = lappend(semi_rhs_exprs, copyObject(right_expr));
    }
 
    /* Punt if we didn't find at least one column to unique-ify */
    if (semi_rhs_exprs == NIL)
        return;
 
    /*
     * The expressions we'd need to unique-ify mustn't be volatile.
     */
    if (contain_volatile_functions((Node *) semi_rhs_exprs))
        return;
 
    /*
     * If we get here, we can unique-ify the semijoin's RHS using at least one
     * of sorting and hashing.  Save the information about how to do that.
     */
    sjinfo->semi_can_btree = all_btree;
    sjinfo->semi_can_hash = all_hash;
    sjinfo->semi_operators = semi_operators;
    sjinfo->semi_rhs_exprs = semi_rhs_exprs;
}

References OpExpr::args, bms_is_empty(), bms_is_subset(), bms_overlap(), bms_union(), contain_volatile_functions(), copyObject, enable_hashagg, exprType(), get_commutator(), get_mergejoin_opfamilies(), IsA, JOIN_SEMI, SpecialJoinInfo::jointype, lappend(), lappend_oid(), lfirst, linitial, list_length(), lsecond, NIL, OidIsValid, op_hashjoinable(), op_mergejoinable(), OpExpr::opno, pull_varnos(), SpecialJoinInfo::semi_can_btree, SpecialJoinInfo::semi_can_hash, SpecialJoinInfo::semi_operators, SpecialJoinInfo::semi_rhs_exprs, and SpecialJoinInfo::syn_righthand.

Referenced by make_outerjoininfo().

create_lateral_join_info()

void create_lateral_join_info

(

PlannerInfo *

root

)

Definition at line 447 of file initsplan.c.

{
    bool        found_laterals = false;
    Index       rti;
    ListCell   *lc;
 
    /* We need do nothing if the query contains no LATERAL RTEs */
    if (!root->hasLateralRTEs)
        return;
 
    /*
     * Examine all baserels (the rel array has been set up by now).
     */
    for (rti = 1; rti < root->simple_rel_array_size; rti++)
    {
        RelOptInfo *brel = root->simple_rel_array[rti];
        Relids      lateral_relids;
 
        /* there may be empty slots corresponding to non-baserel RTEs */
        if (brel == NULL)
            continue;
 
        Assert(brel->relid == rti); /* sanity check on array */
 
        /* ignore RTEs that are "other rels" */
        if (brel->reloptkind != RELOPT_BASEREL)
            continue;
 
        lateral_relids = NULL;
 
        /* consider each laterally-referenced Var or PHV */
        foreach(lc, brel->lateral_vars)
        {
            Node       *node = (Node *) lfirst(lc);
 
            if (IsA(node, Var))
            {
                Var        *var = (Var *) node;
 
                found_laterals = true;
                lateral_relids = bms_add_member(lateral_relids,
                                                var->varno);
            }
            else if (IsA(node, PlaceHolderVar))
            {
                PlaceHolderVar *phv = (PlaceHolderVar *) node;
                PlaceHolderInfo *phinfo = find_placeholder_info(root, phv);
 
                found_laterals = true;
                lateral_relids = bms_add_members(lateral_relids,
                                                 phinfo->ph_eval_at);
            }
            else
                Assert(false);
        }
 
        /* We now have all the simple lateral refs from this rel */
        brel->direct_lateral_relids = lateral_relids;
        brel->lateral_relids = bms_copy(lateral_relids);
    }
 
    /*
     * Now check for lateral references within PlaceHolderVars, and mark their
     * eval_at rels as having lateral references to the source rels.
     *
     * For a PHV that is due to be evaluated at a baserel, mark its source(s)
     * as direct lateral dependencies of the baserel (adding onto the ones
     * recorded above).  If it's due to be evaluated at a join, mark its
     * source(s) as indirect lateral dependencies of each baserel in the join,
     * ie put them into lateral_relids but not direct_lateral_relids.  This is
     * appropriate because we can't put any such baserel on the outside of a
     * join to one of the PHV's lateral dependencies, but on the other hand we
     * also can't yet join it directly to the dependency.
     */
    foreach(lc, root->placeholder_list)
    {
        PlaceHolderInfo *phinfo = (PlaceHolderInfo *) lfirst(lc);
        Relids      eval_at = phinfo->ph_eval_at;
        int         varno;
 
        if (phinfo->ph_lateral == NULL)
            continue;           /* PHV is uninteresting if no lateral refs */
 
        found_laterals = true;
 
        if (bms_get_singleton_member(eval_at, &varno))
        {
            /* Evaluation site is a baserel */
            RelOptInfo *brel = find_base_rel(root, varno);
 
            brel->direct_lateral_relids =
                bms_add_members(brel->direct_lateral_relids,
                                phinfo->ph_lateral);
            brel->lateral_relids =
                bms_add_members(brel->lateral_relids,
                                phinfo->ph_lateral);
        }
        else
        {
            /* Evaluation site is a join */
            varno = -1;
            while ((varno = bms_next_member(eval_at, varno)) >= 0)
            {
                RelOptInfo *brel = find_base_rel(root, varno);
 
                brel->lateral_relids = bms_add_members(brel->lateral_relids,
                                                       phinfo->ph_lateral);
            }
        }
    }
 
    /*
     * If we found no actual lateral references, we're done; but reset the
     * hasLateralRTEs flag to avoid useless work later.
     */
    if (!found_laterals)
    {
        root->hasLateralRTEs = false;
        return;
    }
 
    /*
     * Calculate the transitive closure of the lateral_relids sets, so that
     * they describe both direct and indirect lateral references.  If relation
     * X references Y laterally, and Y references Z laterally, then we will
     * have to scan X on the inside of a nestloop with Z, so for all intents
     * and purposes X is laterally dependent on Z too.
     *
     * This code is essentially Warshall's algorithm for transitive closure.
     * The outer loop considers each baserel, and propagates its lateral
     * dependencies to those baserels that have a lateral dependency on it.
     */
    for (rti = 1; rti < root->simple_rel_array_size; rti++)
    {
        RelOptInfo *brel = root->simple_rel_array[rti];
        Relids      outer_lateral_relids;
        Index       rti2;
 
        if (brel == NULL || brel->reloptkind != RELOPT_BASEREL)
            continue;
 
        /* need not consider baserel further if it has no lateral refs */
        outer_lateral_relids = brel->lateral_relids;
        if (outer_lateral_relids == NULL)
            continue;
 
        /* else scan all baserels */
        for (rti2 = 1; rti2 < root->simple_rel_array_size; rti2++)
        {
            RelOptInfo *brel2 = root->simple_rel_array[rti2];
 
            if (brel2 == NULL || brel2->reloptkind != RELOPT_BASEREL)
                continue;
 
            /* if brel2 has lateral ref to brel, propagate brel's refs */
            if (bms_is_member(rti, brel2->lateral_relids))
                brel2->lateral_relids = bms_add_members(brel2->lateral_relids,
                                                        outer_lateral_relids);
        }
    }
 
    /*
     * Now that we've identified all lateral references, mark each baserel
     * with the set of relids of rels that reference it laterally (possibly
     * indirectly) --- that is, the inverse mapping of lateral_relids.
     */
    for (rti = 1; rti < root->simple_rel_array_size; rti++)
    {
        RelOptInfo *brel = root->simple_rel_array[rti];
        Relids      lateral_relids;
        int         rti2;
 
        if (brel == NULL || brel->reloptkind != RELOPT_BASEREL)
            continue;
 
        /* Nothing to do at rels with no lateral refs */
        lateral_relids = brel->lateral_relids;
        if (lateral_relids == NULL)
            continue;
 
        /*
         * We should not have broken the invariant that lateral_relids is
         * exactly NULL if empty.
         */
        Assert(!bms_is_empty(lateral_relids));
 
        /* Also, no rel should have a lateral dependency on itself */
        Assert(!bms_is_member(rti, lateral_relids));
 
        /* Mark this rel's referencees */
        rti2 = -1;
        while ((rti2 = bms_next_member(lateral_relids, rti2)) >= 0)
        {
            RelOptInfo *brel2 = root->simple_rel_array[rti2];
 
            Assert(brel2 != NULL && brel2->reloptkind == RELOPT_BASEREL);
            brel2->lateral_referencers =
                bms_add_member(brel2->lateral_referencers, rti);
        }
    }
}

References Assert(), bms_add_member(), bms_add_members(), bms_copy(), bms_get_singleton_member(), bms_is_empty(), bms_is_member(), bms_next_member(), RelOptInfo::direct_lateral_relids, find_base_rel(), find_placeholder_info(), PlannerInfo::hasLateralRTEs, IsA, RelOptInfo::lateral_referencers, RelOptInfo::lateral_relids, RelOptInfo::lateral_vars, lfirst, PlaceHolderInfo::ph_eval_at, PlaceHolderInfo::ph_lateral, PlannerInfo::placeholder_list, RelOptInfo::relid, RELOPT_BASEREL, RelOptInfo::reloptkind, PlannerInfo::simple_rel_array_size, and Var::varno.

Referenced by query_planner().

deconstruct_jointree()

List* deconstruct_jointree

(

PlannerInfo *

root

)

Definition at line 683 of file initsplan.c.

{
    List       *result;
    Relids      qualscope;
    Relids      inner_join_rels;
    List       *postponed_qual_list = NIL;
 
    /*
     * After this point, no more PlaceHolderInfos may be made, because
     * make_outerjoininfo and update_placeholder_eval_levels require all
     * active placeholders to be present in root->placeholder_list while we
     * crawl up the join tree.
     */
    root->placeholdersFrozen = true;
 
    /* Start recursion at top of jointree */
    Assert(root->parse->jointree != NULL &&
           IsA(root->parse->jointree, FromExpr));
 
    /* this is filled as we scan the jointree */
    root->nullable_baserels = NULL;
 
    result = deconstruct_recurse(root, (Node *) root->parse->jointree, false,
                                 &qualscope, &inner_join_rels,
                                 &postponed_qual_list);
 
    /* Shouldn't be any leftover quals */
    Assert(postponed_qual_list == NIL);
 
    return result;
}

References Assert(), deconstruct_recurse(), IsA, Query::jointree, NIL, PlannerInfo::nullable_baserels, PlannerInfo::parse, and PlannerInfo::placeholdersFrozen.

Referenced by query_planner().

deconstruct_recurse()

static List * deconstruct_recurse ( PlannerInfo *  root, Node *  jtnode, bool  below_outer_join, Relids *  qualscope, Relids *  inner_join_rels, List **  postponed_qual_list  )

static

Definition at line 737 of file initsplan.c.

{
    List       *joinlist;
 
    if (jtnode == NULL)
    {
        *qualscope = NULL;
        *inner_join_rels = NULL;
        return NIL;
    }
    if (IsA(jtnode, RangeTblRef))
    {
        int         varno = ((RangeTblRef *) jtnode)->rtindex;
 
        /* qualscope is just the one RTE */
        *qualscope = bms_make_singleton(varno);
        /* Deal with any securityQuals attached to the RTE */
        if (root->qual_security_level > 0)
            process_security_barrier_quals(root,
                                           varno,
                                           *qualscope,
                                           below_outer_join);
        /* A single baserel does not create an inner join */
        *inner_join_rels = NULL;
        joinlist = list_make1(jtnode);
    }
    else if (IsA(jtnode, FromExpr))
    {
        FromExpr   *f = (FromExpr *) jtnode;
        List       *child_postponed_quals = NIL;
        int         remaining;
        ListCell   *l;
 
        /*
         * First, recurse to handle child joins.  We collapse subproblems into
         * a single joinlist whenever the resulting joinlist wouldn't exceed
         * from_collapse_limit members.  Also, always collapse one-element
         * subproblems, since that won't lengthen the joinlist anyway.
         */
        *qualscope = NULL;
        *inner_join_rels = NULL;
        joinlist = NIL;
        remaining = list_length(f->fromlist);
        foreach(l, f->fromlist)
        {
            Relids      sub_qualscope;
            List       *sub_joinlist;
            int         sub_members;
 
            sub_joinlist = deconstruct_recurse(root, lfirst(l),
                                               below_outer_join,
                                               &sub_qualscope,
                                               inner_join_rels,
                                               &child_postponed_quals);
            *qualscope = bms_add_members(*qualscope, sub_qualscope);
            sub_members = list_length(sub_joinlist);
            remaining--;
            if (sub_members <= 1 ||
                list_length(joinlist) + sub_members + remaining <= from_collapse_limit)
                joinlist = list_concat(joinlist, sub_joinlist);
            else
                joinlist = lappend(joinlist, sub_joinlist);
        }
 
        /*
         * A FROM with more than one list element is an inner join subsuming
         * all below it, so we should report inner_join_rels = qualscope. If
         * there was exactly one element, we should (and already did) report
         * whatever its inner_join_rels were.  If there were no elements (is
         * that still possible?) the initialization before the loop fixed it.
         */
        if (list_length(f->fromlist) > 1)
            *inner_join_rels = *qualscope;
 
        /*
         * Try to process any quals postponed by children.  If they need
         * further postponement, add them to my output postponed_qual_list.
         */
        foreach(l, child_postponed_quals)
        {
            PostponedQual *pq = (PostponedQual *) lfirst(l);
 
            if (bms_is_subset(pq->relids, *qualscope))
                distribute_qual_to_rels(root, pq->qual,
                                        below_outer_join, JOIN_INNER,
                                        root->qual_security_level,
                                        *qualscope, NULL, NULL,
                                        NULL);
            else
                *postponed_qual_list = lappend(*postponed_qual_list, pq);
        }
 
        /*
         * Now process the top-level quals.
         */
        foreach(l, (List *) f->quals)
        {
            Node       *qual = (Node *) lfirst(l);
 
            distribute_qual_to_rels(root, qual,
                                    below_outer_join, JOIN_INNER,
                                    root->qual_security_level,
                                    *qualscope, NULL, NULL,
                                    postponed_qual_list);
        }
    }
    else if (IsA(jtnode, JoinExpr))
    {
        JoinExpr   *j = (JoinExpr *) jtnode;
        List       *child_postponed_quals = NIL;
        Relids      leftids,
                    rightids,
                    left_inners,
                    right_inners,
                    nonnullable_rels,
                    nullable_rels,
                    ojscope;
        List       *leftjoinlist,
                   *rightjoinlist;
        List       *my_quals;
        SpecialJoinInfo *sjinfo;
        ListCell   *l;
 
        /*
         * Order of operations here is subtle and critical.  First we recurse
         * to handle sub-JOINs.  Their join quals will be placed without
         * regard for whether this level is an outer join, which is correct.
         * Then we place our own join quals, which are restricted by lower
         * outer joins in any case, and are forced to this level if this is an
         * outer join and they mention the outer side.  Finally, if this is an
         * outer join, we create a join_info_list entry for the join.  This
         * will prevent quals above us in the join tree that use those rels
         * from being pushed down below this level.  (It's okay for upper
         * quals to be pushed down to the outer side, however.)
         */
        switch (j->jointype)
        {
            case JOIN_INNER:
                leftjoinlist = deconstruct_recurse(root, j->larg,
                                                   below_outer_join,
                                                   &leftids, &left_inners,
                                                   &child_postponed_quals);
                rightjoinlist = deconstruct_recurse(root, j->rarg,
                                                    below_outer_join,
                                                    &rightids, &right_inners,
                                                    &child_postponed_quals);
                *qualscope = bms_union(leftids, rightids);
                *inner_join_rels = *qualscope;
                /* Inner join adds no restrictions for quals */
                nonnullable_rels = NULL;
                /* and it doesn't force anything to null, either */
                nullable_rels = NULL;
                break;
            case JOIN_LEFT:
            case JOIN_ANTI:
                leftjoinlist = deconstruct_recurse(root, j->larg,
                                                   below_outer_join,
                                                   &leftids, &left_inners,
                                                   &child_postponed_quals);
                rightjoinlist = deconstruct_recurse(root, j->rarg,
                                                    true,
                                                    &rightids, &right_inners,
                                                    &child_postponed_quals);
                *qualscope = bms_union(leftids, rightids);
                *inner_join_rels = bms_union(left_inners, right_inners);
                nonnullable_rels = leftids;
                nullable_rels = rightids;
                break;
            case JOIN_SEMI:
                leftjoinlist = deconstruct_recurse(root, j->larg,
                                                   below_outer_join,
                                                   &leftids, &left_inners,
                                                   &child_postponed_quals);
                rightjoinlist = deconstruct_recurse(root, j->rarg,
                                                    below_outer_join,
                                                    &rightids, &right_inners,
                                                    &child_postponed_quals);
                *qualscope = bms_union(leftids, rightids);
                *inner_join_rels = bms_union(left_inners, right_inners);
                /* Semi join adds no restrictions for quals */
                nonnullable_rels = NULL;
 
                /*
                 * Theoretically, a semijoin would null the RHS; but since the
                 * RHS can't be accessed above the join, this is immaterial
                 * and we needn't account for it.
                 */
                nullable_rels = NULL;
                break;
            case JOIN_FULL:
                leftjoinlist = deconstruct_recurse(root, j->larg,
                                                   true,
                                                   &leftids, &left_inners,
                                                   &child_postponed_quals);
                rightjoinlist = deconstruct_recurse(root, j->rarg,
                                                    true,
                                                    &rightids, &right_inners,
                                                    &child_postponed_quals);
                *qualscope = bms_union(leftids, rightids);
                *inner_join_rels = bms_union(left_inners, right_inners);
                /* each side is both outer and inner */
                nonnullable_rels = *qualscope;
                nullable_rels = *qualscope;
                break;
            default:
                /* JOIN_RIGHT was eliminated during reduce_outer_joins() */
                elog(ERROR, "unrecognized join type: %d",
                     (int) j->jointype);
                nonnullable_rels = NULL;    /* keep compiler quiet */
                nullable_rels = NULL;
                leftjoinlist = rightjoinlist = NIL;
                break;
        }
 
        /* Report all rels that will be nulled anywhere in the jointree */
        root->nullable_baserels = bms_add_members(root->nullable_baserels,
                                                  nullable_rels);
 
        /*
         * Try to process any quals postponed by children.  If they need
         * further postponement, add them to my output postponed_qual_list.
         * Quals that can be processed now must be included in my_quals, so
         * that they'll be handled properly in make_outerjoininfo.
         */
        my_quals = NIL;
        foreach(l, child_postponed_quals)
        {
            PostponedQual *pq = (PostponedQual *) lfirst(l);
 
            if (bms_is_subset(pq->relids, *qualscope))
                my_quals = lappend(my_quals, pq->qual);
            else
            {
                /*
                 * We should not be postponing any quals past an outer join.
                 * If this Assert fires, pull_up_subqueries() messed up.
                 */
                Assert(j->jointype == JOIN_INNER);
                *postponed_qual_list = lappend(*postponed_qual_list, pq);
            }
        }
        my_quals = list_concat(my_quals, (List *) j->quals);
 
        /*
         * For an OJ, form the SpecialJoinInfo now, because we need the OJ's
         * semantic scope (ojscope) to pass to distribute_qual_to_rels.  But
         * we mustn't add it to join_info_list just yet, because we don't want
         * distribute_qual_to_rels to think it is an outer join below us.
         *
         * Semijoins are a bit of a hybrid: we build a SpecialJoinInfo, but we
         * want ojscope = NULL for distribute_qual_to_rels.
         */
        if (j->jointype != JOIN_INNER)
        {
            sjinfo = make_outerjoininfo(root,
                                        leftids, rightids,
                                        *inner_join_rels,
                                        j->jointype,
                                        my_quals);
            if (j->jointype == JOIN_SEMI)
                ojscope = NULL;
            else
                ojscope = bms_union(sjinfo->min_lefthand,
                                    sjinfo->min_righthand);
        }
        else
        {
            sjinfo = NULL;
            ojscope = NULL;
        }
 
        /* Process the JOIN's qual clauses */
        foreach(l, my_quals)
        {
            Node       *qual = (Node *) lfirst(l);
 
            distribute_qual_to_rels(root, qual,
                                    below_outer_join, j->jointype,
                                    root->qual_security_level,
                                    *qualscope,
                                    ojscope, nonnullable_rels,
                                    postponed_qual_list);
        }
 
        /* Now we can add the SpecialJoinInfo to join_info_list */
        if (sjinfo)
        {
            root->join_info_list = lappend(root->join_info_list, sjinfo);
            /* Each time we do that, recheck placeholder eval levels */
            update_placeholder_eval_levels(root, sjinfo);
        }
 
        /*
         * Finally, compute the output joinlist.  We fold subproblems together
         * except at a FULL JOIN or where join_collapse_limit would be
         * exceeded.
         */
        if (j->jointype == JOIN_FULL)
        {
            /* force the join order exactly at this node */
            joinlist = list_make1(list_make2(leftjoinlist, rightjoinlist));
        }
        else if (list_length(leftjoinlist) + list_length(rightjoinlist) <=
                 join_collapse_limit)
        {
            /* OK to combine subproblems */
            joinlist = list_concat(leftjoinlist, rightjoinlist);
        }
        else
        {
            /* can't combine, but needn't force join order above here */
            Node       *leftpart,
                       *rightpart;
 
            /* avoid creating useless 1-element sublists */
            if (list_length(leftjoinlist) == 1)
                leftpart = (Node *) linitial(leftjoinlist);
            else
                leftpart = (Node *) leftjoinlist;
            if (list_length(rightjoinlist) == 1)
                rightpart = (Node *) linitial(rightjoinlist);
            else
                rightpart = (Node *) rightjoinlist;
            joinlist = list_make2(leftpart, rightpart);
        }
    }
    else
    {
        elog(ERROR, "unrecognized node type: %d",
             (int) nodeTag(jtnode));
        joinlist = NIL;         /* keep compiler quiet */
    }
    return joinlist;
}

References Assert(), bms_add_members(), bms_is_subset(), bms_make_singleton(), bms_union(), distribute_qual_to_rels(), elog(), ERROR, from_collapse_limit, FromExpr::fromlist, IsA, j, JOIN_ANTI, join_collapse_limit, JOIN_FULL, PlannerInfo::join_info_list, JOIN_INNER, JOIN_LEFT, JOIN_SEMI, lappend(), lfirst, linitial, list_concat(), list_length(), list_make1, list_make2, make_outerjoininfo(), SpecialJoinInfo::min_lefthand, SpecialJoinInfo::min_righthand, NIL, nodeTag, PlannerInfo::nullable_baserels, process_security_barrier_quals(), PostponedQual::qual, PlannerInfo::qual_security_level, FromExpr::quals, PostponedQual::relids, remaining, and update_placeholder_eval_levels().

Referenced by deconstruct_jointree().

distribute_qual_to_rels()

static void distribute_qual_to_rels ( PlannerInfo *  root, Node *  clause, bool  below_outer_join, JoinType  jointype, Index  security_level, Relids  qualscope, Relids  ojscope, Relids  outerjoin_nonnullable, List **  postponed_qual_list  )

static

Definition at line 1610 of file initsplan.c.

{
    Relids      relids;
    bool        is_pushed_down;
    bool        outerjoin_delayed;
    bool        pseudoconstant = false;
    bool        maybe_equivalence;
    bool        maybe_outer_join;
    Relids      nullable_relids;
    RestrictInfo *restrictinfo;
 
    /*
     * Retrieve all relids mentioned within the clause.
     */
    relids = pull_varnos(root, clause);
 
    /*
     * In ordinary SQL, a WHERE or JOIN/ON clause can't reference any rels
     * that aren't within its syntactic scope; however, if we pulled up a
     * LATERAL subquery then we might find such references in quals that have
     * been pulled up.  We need to treat such quals as belonging to the join
     * level that includes every rel they reference.  Although we could make
     * pull_up_subqueries() place such quals correctly to begin with, it's
     * easier to handle it here.  When we find a clause that contains Vars
     * outside its syntactic scope, we add it to the postponed-quals list, and
     * process it once we've recursed back up to the appropriate join level.
     */
    if (!bms_is_subset(relids, qualscope))
    {
        PostponedQual *pq = (PostponedQual *) palloc(sizeof(PostponedQual));
 
        Assert(root->hasLateralRTEs);   /* shouldn't happen otherwise */
        Assert(jointype == JOIN_INNER); /* mustn't postpone past outer join */
        pq->qual = clause;
        pq->relids = relids;
        *postponed_qual_list = lappend(*postponed_qual_list, pq);
        return;
    }
 
    /*
     * If it's an outer-join clause, also check that relids is a subset of
     * ojscope.  (This should not fail if the syntactic scope check passed.)
     */
    if (ojscope && !bms_is_subset(relids, ojscope))
        elog(ERROR, "JOIN qualification cannot refer to other relations");
 
    /*
     * If the clause is variable-free, our normal heuristic for pushing it
     * down to just the mentioned rels doesn't work, because there are none.
     *
     * If the clause is an outer-join clause, we must force it to the OJ's
     * semantic level to preserve semantics.
     *
     * Otherwise, when the clause contains volatile functions, we force it to
     * be evaluated at its original syntactic level.  This preserves the
     * expected semantics.
     *
     * When the clause contains no volatile functions either, it is actually a
     * pseudoconstant clause that will not change value during any one
     * execution of the plan, and hence can be used as a one-time qual in a
     * gating Result plan node.  We put such a clause into the regular
     * RestrictInfo lists for the moment, but eventually createplan.c will
     * pull it out and make a gating Result node immediately above whatever
     * plan node the pseudoconstant clause is assigned to.  It's usually best
     * to put a gating node as high in the plan tree as possible. If we are
     * not below an outer join, we can actually push the pseudoconstant qual
     * all the way to the top of the tree.  If we are below an outer join, we
     * leave the qual at its original syntactic level (we could push it up to
     * just below the outer join, but that seems more complex than it's
     * worth).
     */
    if (bms_is_empty(relids))
    {
        if (ojscope)
        {
            /* clause is attached to outer join, eval it there */
            relids = bms_copy(ojscope);
            /* mustn't use as gating qual, so don't mark pseudoconstant */
        }
        else
        {
            /* eval at original syntactic level */
            relids = bms_copy(qualscope);
            if (!contain_volatile_functions(clause))
            {
                /* mark as gating qual */
                pseudoconstant = true;
                /* tell createplan.c to check for gating quals */
                root->hasPseudoConstantQuals = true;
                /* if not below outer join, push it to top of tree */
                if (!below_outer_join)
                {
                    relids =
                        get_relids_in_jointree((Node *) root->parse->jointree,
                                               false);
                    qualscope = bms_copy(relids);
                }
            }
        }
    }
 
    /*----------
     * Check to see if clause application must be delayed by outer-join
     * considerations.
     *
     * A word about is_pushed_down: we mark the qual as "pushed down" if
     * it is (potentially) applicable at a level different from its original
     * syntactic level.  This flag is used to distinguish OUTER JOIN ON quals
     * from other quals pushed down to the same joinrel.  The rules are:
     *      WHERE quals and INNER JOIN quals: is_pushed_down = true.
     *      Non-degenerate OUTER JOIN quals: is_pushed_down = false.
     *      Degenerate OUTER JOIN quals: is_pushed_down = true.
     * A "degenerate" OUTER JOIN qual is one that doesn't mention the
     * non-nullable side, and hence can be pushed down into the nullable side
     * without changing the join result.  It is correct to treat it as a
     * regular filter condition at the level where it is evaluated.
     *
     * Note: it is not immediately obvious that a simple boolean is enough
     * for this: if for some reason we were to attach a degenerate qual to
     * its original join level, it would need to be treated as an outer join
     * qual there.  However, this cannot happen, because all the rels the
     * clause mentions must be in the outer join's min_righthand, therefore
     * the join it needs must be formed before the outer join; and we always
     * attach quals to the lowest level where they can be evaluated.  But
     * if we were ever to re-introduce a mechanism for delaying evaluation
     * of "expensive" quals, this area would need work.
     *
     * Note: generally, use of is_pushed_down has to go through the macro
     * RINFO_IS_PUSHED_DOWN, because that flag alone is not always sufficient
     * to tell whether a clause must be treated as pushed-down in context.
     * This seems like another reason why it should perhaps be rethought.
     *----------
     */
    if (bms_overlap(relids, outerjoin_nonnullable))
    {
        /*
         * The qual is attached to an outer join and mentions (some of the)
         * rels on the nonnullable side, so it's not degenerate.
         *
         * We can't use such a clause to deduce equivalence (the left and
         * right sides might be unequal above the join because one of them has
         * gone to NULL) ... but we might be able to use it for more limited
         * deductions, if it is mergejoinable.  So consider adding it to the
         * lists of set-aside outer-join clauses.
         */
        is_pushed_down = false;
        maybe_equivalence = false;
        maybe_outer_join = true;
 
        /* Check to see if must be delayed by lower outer join */
        outerjoin_delayed = check_outerjoin_delay(root,
                                                  &relids,
                                                  &nullable_relids,
                                                  false);
 
        /*
         * Now force the qual to be evaluated exactly at the level of joining
         * corresponding to the outer join.  We cannot let it get pushed down
         * into the nonnullable side, since then we'd produce no output rows,
         * rather than the intended single null-extended row, for any
         * nonnullable-side rows failing the qual.
         *
         * (Do this step after calling check_outerjoin_delay, because that
         * trashes relids.)
         */
        Assert(ojscope);
        relids = ojscope;
        Assert(!pseudoconstant);
    }
    else
    {
        /*
         * Normal qual clause or degenerate outer-join clause.  Either way, we
         * can mark it as pushed-down.
         */
        is_pushed_down = true;
 
        /* Check to see if must be delayed by lower outer join */
        outerjoin_delayed = check_outerjoin_delay(root,
                                                  &relids,
                                                  &nullable_relids,
                                                  true);
 
        if (outerjoin_delayed)
        {
            /* Should still be a subset of current scope ... */
            Assert(root->hasLateralRTEs || bms_is_subset(relids, qualscope));
            Assert(ojscope == NULL || bms_is_subset(relids, ojscope));
 
            /*
             * Because application of the qual will be delayed by outer join,
             * we mustn't assume its vars are equal everywhere.
             */
            maybe_equivalence = false;
 
            /*
             * It's possible that this is an IS NULL clause that's redundant
             * with a lower antijoin; if so we can just discard it.  We need
             * not test in any of the other cases, because this will only be
             * possible for pushed-down, delayed clauses.
             */
            if (check_redundant_nullability_qual(root, clause))
                return;
        }
        else
        {
            /*
             * Qual is not delayed by any lower outer-join restriction, so we
             * can consider feeding it to the equivalence machinery. However,
             * if it's itself within an outer-join clause, treat it as though
             * it appeared below that outer join (note that we can only get
             * here when the clause references only nullable-side rels).
             */
            maybe_equivalence = true;
            if (outerjoin_nonnullable != NULL)
                below_outer_join = true;
        }
 
        /*
         * Since it doesn't mention the LHS, it's certainly not useful as a
         * set-aside OJ clause, even if it's in an OJ.
         */
        maybe_outer_join = false;
    }
 
    /*
     * Build the RestrictInfo node itself.
     */
    restrictinfo = make_restrictinfo(root,
                                     (Expr *) clause,
                                     is_pushed_down,
                                     outerjoin_delayed,
                                     pseudoconstant,
                                     security_level,
                                     relids,
                                     outerjoin_nonnullable,
                                     nullable_relids);
 
    /*
     * If it's a join clause (either naturally, or because delayed by
     * outer-join rules), add vars used in the clause to targetlists of their
     * relations, so that they will be emitted by the plan nodes that scan
     * those relations (else they won't be available at the join node!).
     *
     * Note: if the clause gets absorbed into an EquivalenceClass then this
     * may be unnecessary, but for now we have to do it to cover the case
     * where the EC becomes ec_broken and we end up reinserting the original
     * clauses into the plan.
     */
    if (bms_membership(relids) == BMS_MULTIPLE)
    {
        List       *vars = pull_var_clause(clause,
                                           PVC_RECURSE_AGGREGATES |
                                           PVC_RECURSE_WINDOWFUNCS |
                                           PVC_INCLUDE_PLACEHOLDERS);
 
        add_vars_to_targetlist(root, vars, relids);
        list_free(vars);
    }
 
    /*
     * We check "mergejoinability" of every clause, not only join clauses,
     * because we want to know about equivalences between vars of the same
     * relation, or between vars and consts.
     */
    check_mergejoinable(restrictinfo);
 
    /*
     * If it is a true equivalence clause, send it to the EquivalenceClass
     * machinery.  We do *not* attach it directly to any restriction or join
     * lists.  The EC code will propagate it to the appropriate places later.
     *
     * If the clause has a mergejoinable operator and is not
     * outerjoin-delayed, yet isn't an equivalence because it is an outer-join
     * clause, the EC code may yet be able to do something with it.  We add it
     * to appropriate lists for further consideration later.  Specifically:
     *
     * If it is a left or right outer-join qualification that relates the two
     * sides of the outer join (no funny business like leftvar1 = leftvar2 +
     * rightvar), we add it to root->left_join_clauses or
     * root->right_join_clauses according to which side the nonnullable
     * variable appears on.
     *
     * If it is a full outer-join qualification, we add it to
     * root->full_join_clauses.  (Ideally we'd discard cases that aren't
     * leftvar = rightvar, as we do for left/right joins, but this routine
     * doesn't have the info needed to do that; and the current usage of the
     * full_join_clauses list doesn't require that, so it's not currently
     * worth complicating this routine's API to make it possible.)
     *
     * If none of the above hold, pass it off to
     * distribute_restrictinfo_to_rels().
     *
     * In all cases, it's important to initialize the left_ec and right_ec
     * fields of a mergejoinable clause, so that all possibly mergejoinable
     * expressions have representations in EquivalenceClasses.  If
     * process_equivalence is successful, it will take care of that;
     * otherwise, we have to call initialize_mergeclause_eclasses to do it.
     */
    if (restrictinfo->mergeopfamilies)
    {
        if (maybe_equivalence)
        {
            if (check_equivalence_delay(root, restrictinfo) &&
                process_equivalence(root, &restrictinfo, below_outer_join))
                return;
            /* EC rejected it, so set left_ec/right_ec the hard way ... */
            if (restrictinfo->mergeopfamilies)  /* EC might have changed this */
                initialize_mergeclause_eclasses(root, restrictinfo);
            /* ... and fall through to distribute_restrictinfo_to_rels */
        }
        else if (maybe_outer_join && restrictinfo->can_join)
        {
            /* we need to set up left_ec/right_ec the hard way */
            initialize_mergeclause_eclasses(root, restrictinfo);
            /* now see if it should go to any outer-join lists */
            if (bms_is_subset(restrictinfo->left_relids,
                              outerjoin_nonnullable) &&
                !bms_overlap(restrictinfo->right_relids,
                             outerjoin_nonnullable))
            {
                /* we have outervar = innervar */
                root->left_join_clauses = lappend(root->left_join_clauses,
                                                  restrictinfo);
                return;
            }
            if (bms_is_subset(restrictinfo->right_relids,
                              outerjoin_nonnullable) &&
                !bms_overlap(restrictinfo->left_relids,
                             outerjoin_nonnullable))
            {
                /* we have innervar = outervar */
                root->right_join_clauses = lappend(root->right_join_clauses,
                                                   restrictinfo);
                return;
            }
            if (jointype == JOIN_FULL)
            {
                /* FULL JOIN (above tests cannot match in this case) */
                root->full_join_clauses = lappend(root->full_join_clauses,
                                                  restrictinfo);
                return;
            }
            /* nope, so fall through to distribute_restrictinfo_to_rels */
        }
        else
        {
            /* we still need to set up left_ec/right_ec */
            initialize_mergeclause_eclasses(root, restrictinfo);
        }
    }
 
    /* No EC special case applies, so push it into the clause lists */
    distribute_restrictinfo_to_rels(root, restrictinfo);
}

References add_vars_to_targetlist(), Assert(), bms_copy(), bms_is_empty(), bms_is_subset(), bms_membership(), BMS_MULTIPLE, bms_overlap(), check_equivalence_delay(), check_mergejoinable(), check_outerjoin_delay(), check_redundant_nullability_qual(), contain_volatile_functions(), distribute_restrictinfo_to_rels(), elog(), ERROR, PlannerInfo::full_join_clauses, get_relids_in_jointree(), PlannerInfo::hasLateralRTEs, PlannerInfo::hasPseudoConstantQuals, initialize_mergeclause_eclasses(), JOIN_FULL, JOIN_INNER, Query::jointree, lappend(), PlannerInfo::left_join_clauses, list_free(), make_restrictinfo(), palloc(), PlannerInfo::parse, process_equivalence(), pull_var_clause(), pull_varnos(), PVC_INCLUDE_PLACEHOLDERS, PVC_RECURSE_AGGREGATES, PVC_RECURSE_WINDOWFUNCS, PostponedQual::qual, PostponedQual::relids, and PlannerInfo::right_join_clauses.

Referenced by deconstruct_recurse(), and process_security_barrier_quals().

distribute_restrictinfo_to_rels()

void distribute_restrictinfo_to_rels	(	PlannerInfo *	root,
		RestrictInfo *	restrictinfo
	)

Definition at line 2181 of file initsplan.c.

{
    Relids      relids = restrictinfo->required_relids;
    RelOptInfo *rel;
 
    switch (bms_membership(relids))
    {
        case BMS_SINGLETON:
 
            /*
             * There is only one relation participating in the clause, so it
             * is a restriction clause for that relation.
             */
            rel = find_base_rel(root, bms_singleton_member(relids));
 
            /* Add clause to rel's restriction list */
            rel->baserestrictinfo = lappend(rel->baserestrictinfo,
                                            restrictinfo);
            /* Update security level info */
            rel->baserestrict_min_security = Min(rel->baserestrict_min_security,
                                                 restrictinfo->security_level);
            break;
        case BMS_MULTIPLE:
 
            /*
             * The clause is a join clause, since there is more than one rel
             * in its relid set.
             */
 
            /*
             * Check for hashjoinable operators.  (We don't bother setting the
             * hashjoin info except in true join clauses.)
             */
            check_hashjoinable(restrictinfo);
 
            /*
             * Likewise, check if the clause is suitable to be used with a
             * Memoize node to cache inner tuples during a parameterized
             * nested loop.
             */
            check_memoizable(restrictinfo);
 
            /*
             * Add clause to the join lists of all the relevant relations.
             */
            add_join_clause_to_rels(root, restrictinfo, relids);
            break;
        default:
 
            /*
             * clause references no rels, and therefore we have no place to
             * attach it.  Shouldn't get here if callers are working properly.
             */
            elog(ERROR, "cannot cope with variable-free clause");
            break;
    }
}

References add_join_clause_to_rels(), RelOptInfo::baserestrict_min_security, RelOptInfo::baserestrictinfo, bms_membership(), BMS_MULTIPLE, BMS_SINGLETON, bms_singleton_member(), check_hashjoinable(), check_memoizable(), elog(), ERROR, find_base_rel(), lappend(), Min, RestrictInfo::required_relids, and RestrictInfo::security_level.

Referenced by distribute_qual_to_rels(), generate_base_implied_equalities_broken(), generate_base_implied_equalities_const(), process_implied_equality(), reconsider_outer_join_clauses(), and remove_rel_from_query().

extract_lateral_references()

static void extract_lateral_references ( PlannerInfo *  root, RelOptInfo *  brel, Index  rtindex  )

static

Definition at line 349 of file initsplan.c.

{
    RangeTblEntry *rte = root->simple_rte_array[rtindex];
    List       *vars;
    List       *newvars;
    Relids      where_needed;
    ListCell   *lc;
 
    /* No cross-references are possible if it's not LATERAL */
    if (!rte->lateral)
        return;
 
    /* Fetch the appropriate variables */
    if (rte->rtekind == RTE_RELATION)
        vars = pull_vars_of_level((Node *) rte->tablesample, 0);
    else if (rte->rtekind == RTE_SUBQUERY)
        vars = pull_vars_of_level((Node *) rte->subquery, 1);
    else if (rte->rtekind == RTE_FUNCTION)
        vars = pull_vars_of_level((Node *) rte->functions, 0);
    else if (rte->rtekind == RTE_TABLEFUNC)
        vars = pull_vars_of_level((Node *) rte->tablefunc, 0);
    else if (rte->rtekind == RTE_VALUES)
        vars = pull_vars_of_level((Node *) rte->values_lists, 0);
    else
    {
        Assert(false);
        return;                 /* keep compiler quiet */
    }
 
    if (vars == NIL)
        return;                 /* nothing to do */
 
    /* Copy each Var (or PlaceHolderVar) and adjust it to match our level */
    newvars = NIL;
    foreach(lc, vars)
    {
        Node       *node = (Node *) lfirst(lc);
 
        node = copyObject(node);
        if (IsA(node, Var))
        {
            Var        *var = (Var *) node;
 
            /* Adjustment is easy since it's just one node */
            var->varlevelsup = 0;
        }
        else if (IsA(node, PlaceHolderVar))
        {
            PlaceHolderVar *phv = (PlaceHolderVar *) node;
            int         levelsup = phv->phlevelsup;
 
            /* Have to work harder to adjust the contained expression too */
            if (levelsup != 0)
                IncrementVarSublevelsUp(node, -levelsup, 0);
 
            /*
             * If we pulled the PHV out of a subquery RTE, its expression
             * needs to be preprocessed.  subquery_planner() already did this
             * for level-zero PHVs in function and values RTEs, though.
             */
            if (levelsup > 0)
                phv->phexpr = preprocess_phv_expression(root, phv->phexpr);
        }
        else
            Assert(false);
        newvars = lappend(newvars, node);
    }
 
    list_free(vars);
 
    /*
     * We mark the Vars as being "needed" at the LATERAL RTE.  This is a bit
     * of a cheat: a more formal approach would be to mark each one as needed
     * at the join of the LATERAL RTE with its source RTE.  But it will work,
     * and it's much less tedious than computing a separate where_needed for
     * each Var.
     */
    where_needed = bms_make_singleton(rtindex);
 
    /*
     * Push Vars into their source relations' targetlists, and PHVs into
     * root->placeholder_list.
     */
    add_vars_to_targetlist(root, newvars, where_needed);
 
    /* Remember the lateral references for create_lateral_join_info */
    brel->lateral_vars = newvars;
}

References add_vars_to_targetlist(), Assert(), bms_make_singleton(), copyObject, RangeTblEntry::functions, IncrementVarSublevelsUp(), IsA, lappend(), RangeTblEntry::lateral, RelOptInfo::lateral_vars, lfirst, list_free(), NIL, PlaceHolderVar::phlevelsup, preprocess_phv_expression(), pull_vars_of_level(), RTE_FUNCTION, RTE_RELATION, RTE_SUBQUERY, RTE_TABLEFUNC, RTE_VALUES, RangeTblEntry::rtekind, RangeTblEntry::subquery, RangeTblEntry::tablefunc, RangeTblEntry::tablesample, RangeTblEntry::values_lists, and Var::varlevelsup.

Referenced by find_lateral_references().

find_lateral_references()

void find_lateral_references

(

PlannerInfo *

root

)

Definition at line 301 of file initsplan.c.

{
    Index       rti;
 
    /* We need do nothing if the query contains no LATERAL RTEs */
    if (!root->hasLateralRTEs)
        return;
 
    /*
     * Examine all baserels (the rel array has been set up by now).
     */
    for (rti = 1; rti < root->simple_rel_array_size; rti++)
    {
        RelOptInfo *brel = root->simple_rel_array[rti];
 
        /* there may be empty slots corresponding to non-baserel RTEs */
        if (brel == NULL)
            continue;
 
        Assert(brel->relid == rti); /* sanity check on array */
 
        /*
         * This bit is less obvious than it might look.  We ignore appendrel
         * otherrels and consider only their parent baserels.  In a case where
         * a LATERAL-containing UNION ALL subquery was pulled up, it is the
         * otherrel that is actually going to be in the plan.  However, we
         * want to mark all its lateral references as needed by the parent,
         * because it is the parent's relid that will be used for join
         * planning purposes.  And the parent's RTE will contain all the
         * lateral references we need to know, since the pulled-up member is
         * nothing but a copy of parts of the original RTE's subquery.  We
         * could visit the parent's children instead and transform their
         * references back to the parent's relid, but it would be much more
         * complicated for no real gain.  (Important here is that the child
         * members have not yet received any processing beyond being pulled
         * up.)  Similarly, in appendrels created by inheritance expansion,
         * it's sufficient to look at the parent relation.
         */
 
        /* ignore RTEs that are "other rels" */
        if (brel->reloptkind != RELOPT_BASEREL)
            continue;
 
        extract_lateral_references(root, brel, rti);
    }
}

References Assert(), extract_lateral_references(), PlannerInfo::hasLateralRTEs, RelOptInfo::relid, RELOPT_BASEREL, RelOptInfo::reloptkind, and PlannerInfo::simple_rel_array_size.

Referenced by query_planner().

make_outerjoininfo()

static SpecialJoinInfo * make_outerjoininfo ( PlannerInfo *  root, Relids  left_rels, Relids  right_rels, Relids  inner_join_rels, JoinType  jointype, List *  clause  )

static

Definition at line 1152 of file initsplan.c.

{
    SpecialJoinInfo *sjinfo = makeNode(SpecialJoinInfo);
    Relids      clause_relids;
    Relids      strict_relids;
    Relids      min_lefthand;
    Relids      min_righthand;
    ListCell   *l;
 
    /*
     * We should not see RIGHT JOIN here because left/right were switched
     * earlier
     */
    Assert(jointype != JOIN_INNER);
    Assert(jointype != JOIN_RIGHT);
 
    /*
     * Presently the executor cannot support FOR [KEY] UPDATE/SHARE marking of
     * rels appearing on the nullable side of an outer join. (It's somewhat
     * unclear what that would mean, anyway: what should we mark when a result
     * row is generated from no element of the nullable relation?)  So,
     * complain if any nullable rel is FOR [KEY] UPDATE/SHARE.
     *
     * You might be wondering why this test isn't made far upstream in the
     * parser.  It's because the parser hasn't got enough info --- consider
     * FOR UPDATE applied to a view.  Only after rewriting and flattening do
     * we know whether the view contains an outer join.
     *
     * We use the original RowMarkClause list here; the PlanRowMark list would
     * list everything.
     */
    foreach(l, root->parse->rowMarks)
    {
        RowMarkClause *rc = (RowMarkClause *) lfirst(l);
 
        if (bms_is_member(rc->rti, right_rels) ||
            (jointype == JOIN_FULL && bms_is_member(rc->rti, left_rels)))
            ereport(ERROR,
                    (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
            /*------
             translator: %s is a SQL row locking clause such as FOR UPDATE */
                     errmsg("%s cannot be applied to the nullable side of an outer join",
                            LCS_asString(rc->strength))));
    }
 
    sjinfo->syn_lefthand = left_rels;
    sjinfo->syn_righthand = right_rels;
    sjinfo->jointype = jointype;
    /* this always starts out false */
    sjinfo->delay_upper_joins = false;
 
    compute_semijoin_info(root, sjinfo, clause);
 
    /* If it's a full join, no need to be very smart */
    if (jointype == JOIN_FULL)
    {
        sjinfo->min_lefthand = bms_copy(left_rels);
        sjinfo->min_righthand = bms_copy(right_rels);
        sjinfo->lhs_strict = false; /* don't care about this */
        return sjinfo;
    }
 
    /*
     * Retrieve all relids mentioned within the join clause.
     */
    clause_relids = pull_varnos(root, (Node *) clause);
 
    /*
     * For which relids is the clause strict, ie, it cannot succeed if the
     * rel's columns are all NULL?
     */
    strict_relids = find_nonnullable_rels((Node *) clause);
 
    /* Remember whether the clause is strict for any LHS relations */
    sjinfo->lhs_strict = bms_overlap(strict_relids, left_rels);
 
    /*
     * Required LHS always includes the LHS rels mentioned in the clause. We
     * may have to add more rels based on lower outer joins; see below.
     */
    min_lefthand = bms_intersect(clause_relids, left_rels);
 
    /*
     * Similarly for required RHS.  But here, we must also include any lower
     * inner joins, to ensure we don't try to commute with any of them.
     */
    min_righthand = bms_int_members(bms_union(clause_relids, inner_join_rels),
                                    right_rels);
 
    /*
     * Now check previous outer joins for ordering restrictions.
     */
    foreach(l, root->join_info_list)
    {
        SpecialJoinInfo *otherinfo = (SpecialJoinInfo *) lfirst(l);
 
        /*
         * A full join is an optimization barrier: we can't associate into or
         * out of it.  Hence, if it overlaps either LHS or RHS of the current
         * rel, expand that side's min relset to cover the whole full join.
         */
        if (otherinfo->jointype == JOIN_FULL)
        {
            if (bms_overlap(left_rels, otherinfo->syn_lefthand) ||
                bms_overlap(left_rels, otherinfo->syn_righthand))
            {
                min_lefthand = bms_add_members(min_lefthand,
                                               otherinfo->syn_lefthand);
                min_lefthand = bms_add_members(min_lefthand,
                                               otherinfo->syn_righthand);
            }
            if (bms_overlap(right_rels, otherinfo->syn_lefthand) ||
                bms_overlap(right_rels, otherinfo->syn_righthand))
            {
                min_righthand = bms_add_members(min_righthand,
                                                otherinfo->syn_lefthand);
                min_righthand = bms_add_members(min_righthand,
                                                otherinfo->syn_righthand);
            }
            /* Needn't do anything else with the full join */
            continue;
        }
 
        /*
         * For a lower OJ in our LHS, if our join condition uses the lower
         * join's RHS and is not strict for that rel, we must preserve the
         * ordering of the two OJs, so add lower OJ's full syntactic relset to
         * min_lefthand.  (We must use its full syntactic relset, not just its
         * min_lefthand + min_righthand.  This is because there might be other
         * OJs below this one that this one can commute with, but we cannot
         * commute with them if we don't with this one.)  Also, if the current
         * join is a semijoin or antijoin, we must preserve ordering
         * regardless of strictness.
         *
         * Note: I believe we have to insist on being strict for at least one
         * rel in the lower OJ's min_righthand, not its whole syn_righthand.
         */
        if (bms_overlap(left_rels, otherinfo->syn_righthand))
        {
            if (bms_overlap(clause_relids, otherinfo->syn_righthand) &&
                (jointype == JOIN_SEMI || jointype == JOIN_ANTI ||
                 !bms_overlap(strict_relids, otherinfo->min_righthand)))
            {
                min_lefthand = bms_add_members(min_lefthand,
                                               otherinfo->syn_lefthand);
                min_lefthand = bms_add_members(min_lefthand,
                                               otherinfo->syn_righthand);
            }
        }
 
        /*
         * For a lower OJ in our RHS, if our join condition does not use the
         * lower join's RHS and the lower OJ's join condition is strict, we
         * can interchange the ordering of the two OJs; otherwise we must add
         * the lower OJ's full syntactic relset to min_righthand.
         *
         * Also, if our join condition does not use the lower join's LHS
         * either, force the ordering to be preserved.  Otherwise we can end
         * up with SpecialJoinInfos with identical min_righthands, which can
         * confuse join_is_legal (see discussion in backend/optimizer/README).
         *
         * Also, we must preserve ordering anyway if either the current join
         * or the lower OJ is either a semijoin or an antijoin.
         *
         * Here, we have to consider that "our join condition" includes any
         * clauses that syntactically appeared above the lower OJ and below
         * ours; those are equivalent to degenerate clauses in our OJ and must
         * be treated as such.  Such clauses obviously can't reference our
         * LHS, and they must be non-strict for the lower OJ's RHS (else
         * reduce_outer_joins would have reduced the lower OJ to a plain
         * join).  Hence the other ways in which we handle clauses within our
         * join condition are not affected by them.  The net effect is
         * therefore sufficiently represented by the delay_upper_joins flag
         * saved for us by check_outerjoin_delay.
         */
        if (bms_overlap(right_rels, otherinfo->syn_righthand))
        {
            if (bms_overlap(clause_relids, otherinfo->syn_righthand) ||
                !bms_overlap(clause_relids, otherinfo->min_lefthand) ||
                jointype == JOIN_SEMI ||
                jointype == JOIN_ANTI ||
                otherinfo->jointype == JOIN_SEMI ||
                otherinfo->jointype == JOIN_ANTI ||
                !otherinfo->lhs_strict || otherinfo->delay_upper_joins)
            {
                min_righthand = bms_add_members(min_righthand,
                                                otherinfo->syn_lefthand);
                min_righthand = bms_add_members(min_righthand,
                                                otherinfo->syn_righthand);
            }
        }
    }
 
    /*
     * Examine PlaceHolderVars.  If a PHV is supposed to be evaluated within
     * this join's nullable side, then ensure that min_righthand contains the
     * full eval_at set of the PHV.  This ensures that the PHV actually can be
     * evaluated within the RHS.  Note that this works only because we should
     * already have determined the final eval_at level for any PHV
     * syntactically within this join.
     */
    foreach(l, root->placeholder_list)
    {
        PlaceHolderInfo *phinfo = (PlaceHolderInfo *) lfirst(l);
        Relids      ph_syn_level = phinfo->ph_var->phrels;
 
        /* Ignore placeholder if it didn't syntactically come from RHS */
        if (!bms_is_subset(ph_syn_level, right_rels))
            continue;
 
        /* Else, prevent join from being formed before we eval the PHV */
        min_righthand = bms_add_members(min_righthand, phinfo->ph_eval_at);
    }
 
    /*
     * If we found nothing to put in min_lefthand, punt and make it the full
     * LHS, to avoid having an empty min_lefthand which will confuse later
     * processing. (We don't try to be smart about such cases, just correct.)
     * Likewise for min_righthand.
     */
    if (bms_is_empty(min_lefthand))
        min_lefthand = bms_copy(left_rels);
    if (bms_is_empty(min_righthand))
        min_righthand = bms_copy(right_rels);
 
    /* Now they'd better be nonempty */
    Assert(!bms_is_empty(min_lefthand));
    Assert(!bms_is_empty(min_righthand));
    /* Shouldn't overlap either */
    Assert(!bms_overlap(min_lefthand, min_righthand));
 
    sjinfo->min_lefthand = min_lefthand;
    sjinfo->min_righthand = min_righthand;
 
    return sjinfo;
}

References Assert(), bms_add_members(), bms_copy(), bms_int_members(), bms_intersect(), bms_is_empty(), bms_is_member(), bms_is_subset(), bms_overlap(), bms_union(), compute_semijoin_info(), SpecialJoinInfo::delay_upper_joins, ereport, errcode(), errmsg(), ERROR, find_nonnullable_rels(), JOIN_ANTI, JOIN_FULL, PlannerInfo::join_info_list, JOIN_INNER, JOIN_RIGHT, JOIN_SEMI, SpecialJoinInfo::jointype, LCS_asString(), lfirst, SpecialJoinInfo::lhs_strict, makeNode, SpecialJoinInfo::min_lefthand, SpecialJoinInfo::min_righthand, PlannerInfo::parse, PlaceHolderInfo::ph_eval_at, PlaceHolderInfo::ph_var, PlannerInfo::placeholder_list, pull_varnos(), Query::rowMarks, RowMarkClause::rti, RowMarkClause::strength, SpecialJoinInfo::syn_lefthand, and SpecialJoinInfo::syn_righthand.

Referenced by deconstruct_recurse().

match_foreign_keys_to_quals()

void match_foreign_keys_to_quals

(

PlannerInfo *

root

)

Definition at line 2487 of file initsplan.c.

{
    List       *newlist = NIL;
    ListCell   *lc;
 
    foreach(lc, root->fkey_list)
    {
        ForeignKeyOptInfo *fkinfo = (ForeignKeyOptInfo *) lfirst(lc);
        RelOptInfo *con_rel;
        RelOptInfo *ref_rel;
        int         colno;
 
        /*
         * Either relid might identify a rel that is in the query's rtable but
         * isn't referenced by the jointree so won't have a RelOptInfo.  Hence
         * don't use find_base_rel() here.  We can ignore such FKs.
         */
        if (fkinfo->con_relid >= root->simple_rel_array_size ||
            fkinfo->ref_relid >= root->simple_rel_array_size)
            continue;           /* just paranoia */
        con_rel = root->simple_rel_array[fkinfo->con_relid];
        if (con_rel == NULL)
            continue;
        ref_rel = root->simple_rel_array[fkinfo->ref_relid];
        if (ref_rel == NULL)
            continue;
 
        /*
         * Ignore FK unless both rels are baserels.  This gets rid of FKs that
         * link to inheritance child rels (otherrels) and those that link to
         * rels removed by join removal (dead rels).
         */
        if (con_rel->reloptkind != RELOPT_BASEREL ||
            ref_rel->reloptkind != RELOPT_BASEREL)
            continue;
 
        /*
         * Scan the columns and try to match them to eclasses and quals.
         *
         * Note: for simple inner joins, any match should be in an eclass.
         * "Loose" quals that syntactically match an FK equality must have
         * been rejected for EC status because they are outer-join quals or
         * similar.  We can still consider them to match the FK if they are
         * not outerjoin_delayed.
         */
        for (colno = 0; colno < fkinfo->nkeys; colno++)
        {
            EquivalenceClass *ec;
            AttrNumber  con_attno,
                        ref_attno;
            Oid         fpeqop;
            ListCell   *lc2;
 
            ec = match_eclasses_to_foreign_key_col(root, fkinfo, colno);
            /* Don't bother looking for loose quals if we got an EC match */
            if (ec != NULL)
            {
                fkinfo->nmatched_ec++;
                if (ec->ec_has_const)
                    fkinfo->nconst_ec++;
                continue;
            }
 
            /*
             * Scan joininfo list for relevant clauses.  Either rel's joininfo
             * list would do equally well; we use con_rel's.
             */
            con_attno = fkinfo->conkey[colno];
            ref_attno = fkinfo->confkey[colno];
            fpeqop = InvalidOid;    /* we'll look this up only if needed */
 
            foreach(lc2, con_rel->joininfo)
            {
                RestrictInfo *rinfo = (RestrictInfo *) lfirst(lc2);
                OpExpr     *clause = (OpExpr *) rinfo->clause;
                Var        *leftvar;
                Var        *rightvar;
 
                /* Ignore outerjoin-delayed clauses */
                if (rinfo->outerjoin_delayed)
                    continue;
 
                /* Only binary OpExprs are useful for consideration */
                if (!IsA(clause, OpExpr) ||
                    list_length(clause->args) != 2)
                    continue;
                leftvar = (Var *) get_leftop((Expr *) clause);
                rightvar = (Var *) get_rightop((Expr *) clause);
 
                /* Operands must be Vars, possibly with RelabelType */
                while (leftvar && IsA(leftvar, RelabelType))
                    leftvar = (Var *) ((RelabelType *) leftvar)->arg;
                if (!(leftvar && IsA(leftvar, Var)))
                    continue;
                while (rightvar && IsA(rightvar, RelabelType))
                    rightvar = (Var *) ((RelabelType *) rightvar)->arg;
                if (!(rightvar && IsA(rightvar, Var)))
                    continue;
 
                /* Now try to match the vars to the current foreign key cols */
                if (fkinfo->ref_relid == leftvar->varno &&
                    ref_attno == leftvar->varattno &&
                    fkinfo->con_relid == rightvar->varno &&
                    con_attno == rightvar->varattno)
                {
                    /* Vars match, but is it the right operator? */
                    if (clause->opno == fkinfo->conpfeqop[colno])
                    {
                        fkinfo->rinfos[colno] = lappend(fkinfo->rinfos[colno],
                                                        rinfo);
                        fkinfo->nmatched_ri++;
                    }
                }
                else if (fkinfo->ref_relid == rightvar->varno &&
                         ref_attno == rightvar->varattno &&
                         fkinfo->con_relid == leftvar->varno &&
                         con_attno == leftvar->varattno)
                {
                    /*
                     * Reverse match, must check commutator operator.  Look it
                     * up if we didn't already.  (In the worst case we might
                     * do multiple lookups here, but that would require an FK
                     * equality operator without commutator, which is
                     * unlikely.)
                     */
                    if (!OidIsValid(fpeqop))
                        fpeqop = get_commutator(fkinfo->conpfeqop[colno]);
                    if (clause->opno == fpeqop)
                    {
                        fkinfo->rinfos[colno] = lappend(fkinfo->rinfos[colno],
                                                        rinfo);
                        fkinfo->nmatched_ri++;
                    }
                }
            }
            /* If we found any matching loose quals, count col as matched */
            if (fkinfo->rinfos[colno])
                fkinfo->nmatched_rcols++;
        }
 
        /*
         * Currently, we drop multicolumn FKs that aren't fully matched to the
         * query.  Later we might figure out how to derive some sort of
         * estimate from them, in which case this test should be weakened to
         * "if ((fkinfo->nmatched_ec + fkinfo->nmatched_rcols) > 0)".
         */
        if ((fkinfo->nmatched_ec + fkinfo->nmatched_rcols) == fkinfo->nkeys)
            newlist = lappend(newlist, fkinfo);
    }
    /* Replace fkey_list, thereby discarding any useless entries */
    root->fkey_list = newlist;
}

References OpExpr::args, RestrictInfo::clause, ForeignKeyOptInfo::con_relid, EquivalenceClass::ec_has_const, PlannerInfo::fkey_list, get_commutator(), get_leftop(), get_rightop(), if(), InvalidOid, IsA, RelOptInfo::joininfo, lappend(), lfirst, list_length(), match_eclasses_to_foreign_key_col(), ForeignKeyOptInfo::nconst_ec, NIL, ForeignKeyOptInfo::nkeys, ForeignKeyOptInfo::nmatched_ec, ForeignKeyOptInfo::nmatched_rcols, ForeignKeyOptInfo::nmatched_ri, OidIsValid, OpExpr::opno, RestrictInfo::outerjoin_delayed, ForeignKeyOptInfo::ref_relid, RELOPT_BASEREL, RelOptInfo::reloptkind, ForeignKeyOptInfo::rinfos, and PlannerInfo::simple_rel_array_size.

Referenced by query_planner().

process_implied_equality()

RestrictInfo* process_implied_equality	(	PlannerInfo *	root,
		Oid	opno,
		Oid	collation,
		Expr *	item1,
		Expr *	item2,
		Relids	qualscope,
		Relids	nullable_relids,
		Index	security_level,
		bool	below_outer_join,
		bool	both_const
	)

Definition at line 2276 of file initsplan.c.

{
    RestrictInfo *restrictinfo;
    Node       *clause;
    Relids      relids;
    bool        pseudoconstant = false;
 
    /*
     * Build the new clause.  Copy to ensure it shares no substructure with
     * original (this is necessary in case there are subselects in there...)
     */
    clause = (Node *) make_opclause(opno,
                                    BOOLOID,    /* opresulttype */
                                    false,  /* opretset */
                                    copyObject(item1),
                                    copyObject(item2),
                                    InvalidOid,
                                    collation);
 
    /* If both constant, try to reduce to a boolean constant. */
    if (both_const)
    {
        clause = eval_const_expressions(root, clause);
 
        /* If we produced const TRUE, just drop the clause */
        if (clause && IsA(clause, Const))
        {
            Const      *cclause = (Const *) clause;
 
            Assert(cclause->consttype == BOOLOID);
            if (!cclause->constisnull && DatumGetBool(cclause->constvalue))
                return NULL;
        }
    }
 
    /*
     * The rest of this is a very cut-down version of distribute_qual_to_rels.
     * We can skip most of the work therein, but there are a couple of special
     * cases we still have to handle.
     *
     * Retrieve all relids mentioned within the possibly-simplified clause.
     */
    relids = pull_varnos(root, clause);
    Assert(bms_is_subset(relids, qualscope));
 
    /*
     * If the clause is variable-free, our normal heuristic for pushing it
     * down to just the mentioned rels doesn't work, because there are none.
     * Apply at the given qualscope, or at the top of tree if it's nonvolatile
     * (which it very likely is, but we'll check, just to be sure).
     */
    if (bms_is_empty(relids))
    {
        /* eval at original syntactic level */
        relids = bms_copy(qualscope);
        if (!contain_volatile_functions(clause))
        {
            /* mark as gating qual */
            pseudoconstant = true;
            /* tell createplan.c to check for gating quals */
            root->hasPseudoConstantQuals = true;
            /* if not below outer join, push it to top of tree */
            if (!below_outer_join)
            {
                relids =
                    get_relids_in_jointree((Node *) root->parse->jointree,
                                           false);
            }
        }
    }
 
    /*
     * Build the RestrictInfo node itself.
     */
    restrictinfo = make_restrictinfo(root,
                                     (Expr *) clause,
                                     true,  /* is_pushed_down */
                                     false, /* outerjoin_delayed */
                                     pseudoconstant,
                                     security_level,
                                     relids,
                                     NULL,  /* outer_relids */
                                     nullable_relids);
 
    /*
     * If it's a join clause, add vars used in the clause to targetlists of
     * their relations, so that they will be emitted by the plan nodes that
     * scan those relations (else they won't be available at the join node!).
     *
     * Typically, we'd have already done this when the component expressions
     * were first seen by distribute_qual_to_rels; but it is possible that
     * some of the Vars could have missed having that done because they only
     * appeared in single-relation clauses originally.  So do it here for
     * safety.
     */
    if (bms_membership(relids) == BMS_MULTIPLE)
    {
        List       *vars = pull_var_clause(clause,
                                           PVC_RECURSE_AGGREGATES |
                                           PVC_RECURSE_WINDOWFUNCS |
                                           PVC_INCLUDE_PLACEHOLDERS);
 
        add_vars_to_targetlist(root, vars, relids);
        list_free(vars);
    }
 
    /*
     * Check mergejoinability.  This will usually succeed, since the op came
     * from an EquivalenceClass; but we could have reduced the original clause
     * to a constant.
     */
    check_mergejoinable(restrictinfo);
 
    /*
     * Note we don't do initialize_mergeclause_eclasses(); the caller can
     * handle that much more cheaply than we can.  It's okay to call
     * distribute_restrictinfo_to_rels() before that happens.
     */
 
    /*
     * Push the new clause into all the appropriate restrictinfo lists.
     */
    distribute_restrictinfo_to_rels(root, restrictinfo);
 
    return restrictinfo;
}

References add_vars_to_targetlist(), Assert(), bms_copy(), bms_is_empty(), bms_is_subset(), bms_membership(), BMS_MULTIPLE, check_mergejoinable(), Const::constisnull, Const::consttype, Const::constvalue, contain_volatile_functions(), copyObject, DatumGetBool(), distribute_restrictinfo_to_rels(), eval_const_expressions(), get_relids_in_jointree(), PlannerInfo::hasPseudoConstantQuals, InvalidOid, IsA, Query::jointree, list_free(), make_opclause(), make_restrictinfo(), PlannerInfo::parse, pull_var_clause(), pull_varnos(), PVC_INCLUDE_PLACEHOLDERS, PVC_RECURSE_AGGREGATES, and PVC_RECURSE_WINDOWFUNCS.

Referenced by generate_base_implied_equalities_const(), and generate_base_implied_equalities_no_const().

process_security_barrier_quals()

static void process_security_barrier_quals ( PlannerInfo *  root, int  rti, Relids  qualscope, bool  below_outer_join  )

static

Definition at line 1088 of file initsplan.c.

{
    RangeTblEntry *rte = root->simple_rte_array[rti];
    Index       security_level = 0;
    ListCell   *lc;
 
    /*
     * Each element of the securityQuals list has been preprocessed into an
     * implicitly-ANDed list of clauses.  All the clauses in a given sublist
     * should get the same security level, but successive sublists get higher
     * levels.
     */
    foreach(lc, rte->securityQuals)
    {
        List       *qualset = (List *) lfirst(lc);
        ListCell   *lc2;
 
        foreach(lc2, qualset)
        {
            Node       *qual = (Node *) lfirst(lc2);
 
            /*
             * We cheat to the extent of passing ojscope = qualscope rather
             * than its more logical value of NULL.  The only effect this has
             * is to force a Var-free qual to be evaluated at the rel rather
             * than being pushed up to top of tree, which we don't want.
             */
            distribute_qual_to_rels(root, qual,
                                    below_outer_join,
                                    JOIN_INNER,
                                    security_level,
                                    qualscope,
                                    qualscope,
                                    NULL,
                                    NULL);
        }
        security_level++;
    }
 
    /* Assert that qual_security_level is higher than anything we just used */
    Assert(security_level <= root->qual_security_level);
}

References Assert(), distribute_qual_to_rels(), JOIN_INNER, lfirst, and RangeTblEntry::securityQuals.

Referenced by deconstruct_recurse().

Variable Documentation

from_collapse_limit

int from_collapse_limit

Definition at line 39 of file initsplan.c.

Referenced by deconstruct_recurse().

join_collapse_limit

int join_collapse_limit

Definition at line 40 of file initsplan.c.

Referenced by deconstruct_recurse().