indxpath.c File Reference

#include "postgres.h"
#include <math.h>
#include "access/stratnum.h"
#include "access/sysattr.h"
#include "catalog/pg_am.h"
#include "catalog/pg_operator.h"
#include "catalog/pg_opfamily.h"
#include "catalog/pg_type.h"
#include "nodes/makefuncs.h"
#include "nodes/nodeFuncs.h"
#include "nodes/supportnodes.h"
#include "optimizer/cost.h"
#include "optimizer/optimizer.h"
#include "optimizer/pathnode.h"
#include "optimizer/paths.h"
#include "optimizer/prep.h"
#include "optimizer/restrictinfo.h"
#include "utils/lsyscache.h"
#include "utils/selfuncs.h"

Include dependency graph for indxpath.c:

Go to the source code of this file.

Data Structures
struct	IndexClauseSet
struct	PathClauseUsage
struct	ec_member_matches_arg

Macros
#define	IndexCollMatchesExprColl(idxcollation, exprcollation)   ((idxcollation) == InvalidOid || (idxcollation) == (exprcollation))

Enumerations
enum	ScanTypeControl { ST_INDEXSCAN, ST_BITMAPSCAN, ST_ANYSCAN }

Functions
static void	consider_index_join_clauses (PlannerInfo *root, RelOptInfo *rel, IndexOptInfo *index, IndexClauseSet *rclauseset, IndexClauseSet *jclauseset, IndexClauseSet *eclauseset, List **bitindexpaths)
static void	consider_index_join_outer_rels (PlannerInfo *root, RelOptInfo *rel, IndexOptInfo *index, IndexClauseSet *rclauseset, IndexClauseSet *jclauseset, IndexClauseSet *eclauseset, List **bitindexpaths, List *indexjoinclauses, int considered_clauses, List **considered_relids)
static void	get_join_index_paths (PlannerInfo *root, RelOptInfo *rel, IndexOptInfo *index, IndexClauseSet *rclauseset, IndexClauseSet *jclauseset, IndexClauseSet *eclauseset, List **bitindexpaths, Relids relids, List **considered_relids)
static bool	eclass_already_used (EquivalenceClass *parent_ec, Relids oldrelids, List *indexjoinclauses)
static bool	bms_equal_any (Relids relids, List *relids_list)
static void	get_index_paths (PlannerInfo *root, RelOptInfo *rel, IndexOptInfo *index, IndexClauseSet *clauses, List **bitindexpaths)
static List *	build_index_paths (PlannerInfo *root, RelOptInfo *rel, IndexOptInfo *index, IndexClauseSet *clauses, bool useful_predicate, ScanTypeControl scantype, bool *skip_nonnative_saop, bool *skip_lower_saop)
static List *	build_paths_for_OR (PlannerInfo *root, RelOptInfo *rel, List *clauses, List *other_clauses)
static List *	generate_bitmap_or_paths (PlannerInfo *root, RelOptInfo *rel, List *clauses, List *other_clauses)
static Path *	choose_bitmap_and (PlannerInfo *root, RelOptInfo *rel, List *paths)
static int	path_usage_comparator (const void *a, const void *b)
static Cost	bitmap_scan_cost_est (PlannerInfo *root, RelOptInfo *rel, Path *ipath)
static Cost	bitmap_and_cost_est (PlannerInfo *root, RelOptInfo *rel, List *paths)
static PathClauseUsage *	classify_index_clause_usage (Path *path, List **clauselist)
static Relids	get_bitmap_tree_required_outer (Path *bitmapqual)
static void	find_indexpath_quals (Path *bitmapqual, List **quals, List **preds)
static int	find_list_position (Node *node, List **nodelist)
static bool	check_index_only (RelOptInfo *rel, IndexOptInfo *index)
static double	get_loop_count (PlannerInfo *root, Index cur_relid, Relids outer_relids)
static double	adjust_rowcount_for_semijoins (PlannerInfo *root, Index cur_relid, Index outer_relid, double rowcount)
static double	approximate_joinrel_size (PlannerInfo *root, Relids relids)
static void	match_restriction_clauses_to_index (PlannerInfo *root, IndexOptInfo *index, IndexClauseSet *clauseset)
static void	match_join_clauses_to_index (PlannerInfo *root, RelOptInfo *rel, IndexOptInfo *index, IndexClauseSet *clauseset, List **joinorclauses)
static void	match_eclass_clauses_to_index (PlannerInfo *root, IndexOptInfo *index, IndexClauseSet *clauseset)
static void	match_clauses_to_index (PlannerInfo *root, List *clauses, IndexOptInfo *index, IndexClauseSet *clauseset)
static void	match_clause_to_index (PlannerInfo *root, RestrictInfo *rinfo, IndexOptInfo *index, IndexClauseSet *clauseset)
static IndexClause *	match_clause_to_indexcol (PlannerInfo *root, RestrictInfo *rinfo, int indexcol, IndexOptInfo *index)
static IndexClause *	match_boolean_index_clause (RestrictInfo *rinfo, int indexcol, IndexOptInfo *index)
static IndexClause *	match_opclause_to_indexcol (PlannerInfo *root, RestrictInfo *rinfo, int indexcol, IndexOptInfo *index)
static IndexClause *	match_funcclause_to_indexcol (PlannerInfo *root, RestrictInfo *rinfo, int indexcol, IndexOptInfo *index)
static IndexClause *	get_index_clause_from_support (PlannerInfo *root, RestrictInfo *rinfo, Oid funcid, int indexarg, int indexcol, IndexOptInfo *index)
static IndexClause *	match_saopclause_to_indexcol (RestrictInfo *rinfo, int indexcol, IndexOptInfo *index)
static IndexClause *	match_rowcompare_to_indexcol (RestrictInfo *rinfo, int indexcol, IndexOptInfo *index)
static IndexClause *	expand_indexqual_rowcompare (RestrictInfo *rinfo, int indexcol, IndexOptInfo *index, Oid expr_op, bool var_on_left)
static void	match_pathkeys_to_index (IndexOptInfo *index, List *pathkeys, List **orderby_clauses_p, List **clause_columns_p)
static Expr *	match_clause_to_ordering_op (IndexOptInfo *index, int indexcol, Expr *clause, Oid pk_opfamily)
static bool	ec_member_matches_indexcol (PlannerInfo *root, RelOptInfo *rel, EquivalenceClass *ec, EquivalenceMember *em, void *arg)
void	create_index_paths (PlannerInfo *root, RelOptInfo *rel)
void	check_index_predicates (PlannerInfo *root, RelOptInfo *rel)
bool	relation_has_unique_index_for (PlannerInfo *root, RelOptInfo *rel, List *restrictlist, List *exprlist, List *oprlist)
bool	indexcol_is_bool_constant_for_query (IndexOptInfo *index, int indexcol)
bool	match_index_to_operand (Node *operand, int indexcol, IndexOptInfo *index)
bool	is_pseudo_constant_for_index (Node *expr, IndexOptInfo *index)

Macro Definition Documentation

IndexCollMatchesExprColl

#define IndexCollMatchesExprColl	(		idxcollation,
			exprcollation
	)		((idxcollation) == InvalidOid || (idxcollation) == (exprcollation))

Definition at line 40 of file indxpath.c.

Referenced by ec_member_matches_indexcol(), expand_indexqual_rowcompare(), match_clause_to_ordering_op(), match_opclause_to_indexcol(), match_rowcompare_to_indexcol(), and match_saopclause_to_indexcol().

Enumeration Type Documentation

ScanTypeControl

enum ScanTypeControl

Enumerator
ST_INDEXSCAN
ST_BITMAPSCAN
ST_ANYSCAN

Definition at line 44 of file indxpath.c.

{
    ST_INDEXSCAN,               /* must support amgettuple */
    ST_BITMAPSCAN,              /* must support amgetbitmap */
    ST_ANYSCAN                  /* either is okay */
} ScanTypeControl;

Function Documentation

adjust_rowcount_for_semijoins()

static double adjust_rowcount_for_semijoins ( PlannerInfo *  root, Index  cur_relid, Index  outer_relid, double  rowcount  )

static

Definition at line 2053 of file indxpath.c.

References approximate_joinrel_size(), bms_is_member(), estimate_num_groups(), PlannerInfo::join_info_list, JOIN_SEMI, SpecialJoinInfo::jointype, lfirst, SpecialJoinInfo::semi_rhs_exprs, SpecialJoinInfo::syn_lefthand, and SpecialJoinInfo::syn_righthand.

Referenced by get_loop_count().

{
    ListCell   *lc;

    foreach(lc, root->join_info_list)
    {
        SpecialJoinInfo *sjinfo = (SpecialJoinInfo *) lfirst(lc);

        if (sjinfo->jointype == JOIN_SEMI &&
            bms_is_member(cur_relid, sjinfo->syn_lefthand) &&
            bms_is_member(outer_relid, sjinfo->syn_righthand))
        {
            /* Estimate number of unique-ified rows */
            double      nraw;
            double      nunique;

            nraw = approximate_joinrel_size(root, sjinfo->syn_righthand);
            nunique = estimate_num_groups(root,
                                          sjinfo->semi_rhs_exprs,
                                          nraw,
                                          NULL);
            if (rowcount > nunique)
                rowcount = nunique;
        }
    }
    return rowcount;
}

approximate_joinrel_size()

static double approximate_joinrel_size ( PlannerInfo *  root, Relids  relids  )

static

Definition at line 2096 of file indxpath.c.

References Assert, bms_next_member(), IS_DUMMY_REL, RelOptInfo::relid, RelOptInfo::rows, PlannerInfo::simple_rel_array, and PlannerInfo::simple_rel_array_size.

Referenced by adjust_rowcount_for_semijoins().

{
    double      rowcount = 1.0;
    int         relid;

    relid = -1;
    while ((relid = bms_next_member(relids, relid)) >= 0)
    {
        RelOptInfo *rel;

        /* Paranoia: ignore bogus relid indexes */
        if (relid >= root->simple_rel_array_size)
            continue;
        rel = root->simple_rel_array[relid];
        if (rel == NULL)
            continue;
        Assert(rel->relid == relid);    /* sanity check on array */

        /* Relation could be proven empty, if so ignore */
        if (IS_DUMMY_REL(rel))
            continue;

        /* Otherwise, rel's rows estimate should be valid by now */
        Assert(rel->rows > 0);

        /* Accumulate product */
        rowcount *= rel->rows;
    }
    return rowcount;
}

bitmap_and_cost_est()

static Cost bitmap_and_cost_est ( PlannerInfo *  root, RelOptInfo *  rel, List *  paths  )

static

Definition at line 1644 of file indxpath.c.

References BitmapHeapPath::bitmapqual, BitmapAndPath::bitmapquals, cost_bitmap_and_node(), cost_bitmap_heap_scan(), get_baserel_parampathinfo(), get_bitmap_tree_required_outer(), get_loop_count(), NIL, Path::parallel_workers, Path::param_info, Path::parent, BitmapHeapPath::path, BitmapAndPath::path, Path::pathkeys, Path::pathtarget, Path::pathtype, RelOptInfo::relid, RelOptInfo::reltarget, T_BitmapAnd, T_BitmapAndPath, T_BitmapHeapPath, T_BitmapHeapScan, Path::total_cost, and Path::type.

Referenced by choose_bitmap_and().

{
    BitmapAndPath apath;
    BitmapHeapPath bpath;
    Relids      required_outer;

    /* Set up a dummy BitmapAndPath */
    apath.path.type = T_BitmapAndPath;
    apath.path.pathtype = T_BitmapAnd;
    apath.path.parent = rel;
    apath.path.pathtarget = rel->reltarget;
    apath.path.param_info = NULL;   /* not used in bitmap trees */
    apath.path.pathkeys = NIL;
    apath.bitmapquals = paths;
    cost_bitmap_and_node(&apath, root);

    /* Identify required outer rels, in case it's a parameterized scan */
    required_outer = get_bitmap_tree_required_outer((Path *) &apath);

    /* Set up a dummy BitmapHeapPath */
    bpath.path.type = T_BitmapHeapPath;
    bpath.path.pathtype = T_BitmapHeapScan;
    bpath.path.parent = rel;
    bpath.path.pathtarget = rel->reltarget;
    bpath.path.param_info = get_baserel_parampathinfo(root, rel,
                                                      required_outer);
    bpath.path.pathkeys = NIL;
    bpath.bitmapqual = (Path *) &apath;

    /*
     * Check the cost of temporary path without considering parallelism.
     * Parallel bitmap heap path will be considered at later stage.
     */
    bpath.path.parallel_workers = 0;

    /* Now we can do cost_bitmap_heap_scan */
    cost_bitmap_heap_scan(&bpath.path, root, rel,
                          bpath.path.param_info,
                          (Path *) &apath,
                          get_loop_count(root, rel->relid, required_outer));

    return bpath.path.total_cost;
}

bitmap_scan_cost_est()

static Cost bitmap_scan_cost_est ( PlannerInfo *  root, RelOptInfo *  rel, Path *  ipath  )

static

Definition at line 1608 of file indxpath.c.

References BitmapHeapPath::bitmapqual, cost_bitmap_heap_scan(), get_baserel_parampathinfo(), get_bitmap_tree_required_outer(), get_loop_count(), NIL, Path::parallel_workers, Path::param_info, Path::parent, BitmapHeapPath::path, Path::pathkeys, Path::pathtarget, Path::pathtype, RelOptInfo::relid, RelOptInfo::reltarget, T_BitmapHeapPath, T_BitmapHeapScan, Path::total_cost, and Path::type.

Referenced by choose_bitmap_and().

{
    BitmapHeapPath bpath;
    Relids      required_outer;

    /* Identify required outer rels, in case it's a parameterized scan */
    required_outer = get_bitmap_tree_required_outer(ipath);

    /* Set up a dummy BitmapHeapPath */
    bpath.path.type = T_BitmapHeapPath;
    bpath.path.pathtype = T_BitmapHeapScan;
    bpath.path.parent = rel;
    bpath.path.pathtarget = rel->reltarget;
    bpath.path.param_info = get_baserel_parampathinfo(root, rel,
                                                      required_outer);
    bpath.path.pathkeys = NIL;
    bpath.bitmapqual = ipath;

    /*
     * Check the cost of temporary path without considering parallelism.
     * Parallel bitmap heap path will be considered at later stage.
     */
    bpath.path.parallel_workers = 0;
    cost_bitmap_heap_scan(&bpath.path, root, rel,
                          bpath.path.param_info,
                          ipath,
                          get_loop_count(root, rel->relid, required_outer));

    return bpath.path.total_cost;
}

bms_equal_any()

static bool bms_equal_any ( Relids  relids, List *  relids_list  )

static

Definition at line 710 of file indxpath.c.

References bms_equal(), and lfirst.

Referenced by consider_index_join_outer_rels(), create_index_paths(), and get_join_index_paths().

{
    ListCell   *lc;

    foreach(lc, relids_list)
    {
        if (bms_equal(relids, (Relids) lfirst(lc)))
            return true;
    }
    return false;
}

build_index_paths()

static List * build_index_paths ( PlannerInfo *  root, RelOptInfo *  rel, IndexOptInfo *  index, IndexClauseSet *  clauses, bool  useful_predicate, ScanTypeControl  scantype, bool *  skip_nonnative_saop, bool *  skip_lower_saop  )

static

Definition at line 861 of file indxpath.c.

References add_partial_path(), IndexOptInfo::amcanorderbyop, IndexOptInfo::amcanparallel, IndexOptInfo::amhasgetbitmap, IndexOptInfo::amhasgettuple, IndexOptInfo::amoptionalkey, IndexOptInfo::amsearcharray, Assert, BackwardScanDirection, bms_add_members(), bms_copy(), bms_del_member(), bms_is_empty(), build_index_pathkeys(), check_index_only(), RestrictInfo::clause, RestrictInfo::clause_relids, RelOptInfo::consider_parallel, create_index_path(), ForwardScanDirection, get_loop_count(), has_useful_pathkeys(), IndexClauseSet::indexclauses, IsA, lappend(), RelOptInfo::lateral_relids, lfirst, match_pathkeys_to_index(), NIL, IndexOptInfo::nkeycolumns, NoMovementScanDirection, Path::parallel_workers, IndexPath::path, pfree(), PlannerInfo::query_pathkeys, RelOptInfo::relid, IndexClause::rinfo, IndexOptInfo::sortopfamily, ST_ANYSCAN, ST_BITMAPSCAN, ST_INDEXSCAN, and truncate_useless_pathkeys().

Referenced by build_paths_for_OR(), and get_index_paths().

{
    List       *result = NIL;
    IndexPath  *ipath;
    List       *index_clauses;
    Relids      outer_relids;
    double      loop_count;
    List       *orderbyclauses;
    List       *orderbyclausecols;
    List       *index_pathkeys;
    List       *useful_pathkeys;
    bool        found_lower_saop_clause;
    bool        pathkeys_possibly_useful;
    bool        index_is_ordered;
    bool        index_only_scan;
    int         indexcol;

    /*
     * Check that index supports the desired scan type(s)
     */
    switch (scantype)
    {
        case ST_INDEXSCAN:
            if (!index->amhasgettuple)
                return NIL;
            break;
        case ST_BITMAPSCAN:
            if (!index->amhasgetbitmap)
                return NIL;
            break;
        case ST_ANYSCAN:
            /* either or both are OK */
            break;
    }

    /*
     * 1. Combine the per-column IndexClause lists into an overall list.
     *
     * In the resulting list, clauses are ordered by index key, so that the
     * column numbers form a nondecreasing sequence.  (This order is depended
     * on by btree and possibly other places.)  The list can be empty, if the
     * index AM allows that.
     *
     * found_lower_saop_clause is set true if we accept a ScalarArrayOpExpr
     * index clause for a non-first index column.  This prevents us from
     * assuming that the scan result is ordered.  (Actually, the result is
     * still ordered if there are equality constraints for all earlier
     * columns, but it seems too expensive and non-modular for this code to be
     * aware of that refinement.)
     *
     * We also build a Relids set showing which outer rels are required by the
     * selected clauses.  Any lateral_relids are included in that, but not
     * otherwise accounted for.
     */
    index_clauses = NIL;
    found_lower_saop_clause = false;
    outer_relids = bms_copy(rel->lateral_relids);
    for (indexcol = 0; indexcol < index->nkeycolumns; indexcol++)
    {
        ListCell   *lc;

        foreach(lc, clauses->indexclauses[indexcol])
        {
            IndexClause *iclause = (IndexClause *) lfirst(lc);
            RestrictInfo *rinfo = iclause->rinfo;

            /* We might need to omit ScalarArrayOpExpr clauses */
            if (IsA(rinfo->clause, ScalarArrayOpExpr))
            {
                if (!index->amsearcharray)
                {
                    if (skip_nonnative_saop)
                    {
                        /* Ignore because not supported by index */
                        *skip_nonnative_saop = true;
                        continue;
                    }
                    /* Caller had better intend this only for bitmap scan */
                    Assert(scantype == ST_BITMAPSCAN);
                }
                if (indexcol > 0)
                {
                    if (skip_lower_saop)
                    {
                        /* Caller doesn't want to lose index ordering */
                        *skip_lower_saop = true;
                        continue;
                    }
                    found_lower_saop_clause = true;
                }
            }

            /* OK to include this clause */
            index_clauses = lappend(index_clauses, iclause);
            outer_relids = bms_add_members(outer_relids,
                                           rinfo->clause_relids);
        }

        /*
         * If no clauses match the first index column, check for amoptionalkey
         * restriction.  We can't generate a scan over an index with
         * amoptionalkey = false unless there's at least one index clause.
         * (When working on columns after the first, this test cannot fail. It
         * is always okay for columns after the first to not have any
         * clauses.)
         */
        if (index_clauses == NIL && !index->amoptionalkey)
            return NIL;
    }

    /* We do not want the index's rel itself listed in outer_relids */
    outer_relids = bms_del_member(outer_relids, rel->relid);
    /* Enforce convention that outer_relids is exactly NULL if empty */
    if (bms_is_empty(outer_relids))
        outer_relids = NULL;

    /* Compute loop_count for cost estimation purposes */
    loop_count = get_loop_count(root, rel->relid, outer_relids);

    /*
     * 2. Compute pathkeys describing index's ordering, if any, then see how
     * many of them are actually useful for this query.  This is not relevant
     * if we are only trying to build bitmap indexscans, nor if we have to
     * assume the scan is unordered.
     */
    pathkeys_possibly_useful = (scantype != ST_BITMAPSCAN &&
                                !found_lower_saop_clause &&
                                has_useful_pathkeys(root, rel));
    index_is_ordered = (index->sortopfamily != NULL);
    if (index_is_ordered && pathkeys_possibly_useful)
    {
        index_pathkeys = build_index_pathkeys(root, index,
                                              ForwardScanDirection);
        useful_pathkeys = truncate_useless_pathkeys(root, rel,
                                                    index_pathkeys);
        orderbyclauses = NIL;
        orderbyclausecols = NIL;
    }
    else if (index->amcanorderbyop && pathkeys_possibly_useful)
    {
        /* see if we can generate ordering operators for query_pathkeys */
        match_pathkeys_to_index(index, root->query_pathkeys,
                                &orderbyclauses,
                                &orderbyclausecols);
        if (orderbyclauses)
            useful_pathkeys = root->query_pathkeys;
        else
            useful_pathkeys = NIL;
    }
    else
    {
        useful_pathkeys = NIL;
        orderbyclauses = NIL;
        orderbyclausecols = NIL;
    }

    /*
     * 3. Check if an index-only scan is possible.  If we're not building
     * plain indexscans, this isn't relevant since bitmap scans don't support
     * index data retrieval anyway.
     */
    index_only_scan = (scantype != ST_BITMAPSCAN &&
                       check_index_only(rel, index));

    /*
     * 4. Generate an indexscan path if there are relevant restriction clauses
     * in the current clauses, OR the index ordering is potentially useful for
     * later merging or final output ordering, OR the index has a useful
     * predicate, OR an index-only scan is possible.
     */
    if (index_clauses != NIL || useful_pathkeys != NIL || useful_predicate ||
        index_only_scan)
    {
        ipath = create_index_path(root, index,
                                  index_clauses,
                                  orderbyclauses,
                                  orderbyclausecols,
                                  useful_pathkeys,
                                  index_is_ordered ?
                                  ForwardScanDirection :
                                  NoMovementScanDirection,
                                  index_only_scan,
                                  outer_relids,
                                  loop_count,
                                  false);
        result = lappend(result, ipath);

        /*
         * If appropriate, consider parallel index scan.  We don't allow
         * parallel index scan for bitmap index scans.
         */
        if (index->amcanparallel &&
            rel->consider_parallel && outer_relids == NULL &&
            scantype != ST_BITMAPSCAN)
        {
            ipath = create_index_path(root, index,
                                      index_clauses,
                                      orderbyclauses,
                                      orderbyclausecols,
                                      useful_pathkeys,
                                      index_is_ordered ?
                                      ForwardScanDirection :
                                      NoMovementScanDirection,
                                      index_only_scan,
                                      outer_relids,
                                      loop_count,
                                      true);

            /*
             * if, after costing the path, we find that it's not worth using
             * parallel workers, just free it.
             */
            if (ipath->path.parallel_workers > 0)
                add_partial_path(rel, (Path *) ipath);
            else
                pfree(ipath);
        }
    }

    /*
     * 5. If the index is ordered, a backwards scan might be interesting.
     */
    if (index_is_ordered && pathkeys_possibly_useful)
    {
        index_pathkeys = build_index_pathkeys(root, index,
                                              BackwardScanDirection);
        useful_pathkeys = truncate_useless_pathkeys(root, rel,
                                                    index_pathkeys);
        if (useful_pathkeys != NIL)
        {
            ipath = create_index_path(root, index,
                                      index_clauses,
                                      NIL,
                                      NIL,
                                      useful_pathkeys,
                                      BackwardScanDirection,
                                      index_only_scan,
                                      outer_relids,
                                      loop_count,
                                      false);
            result = lappend(result, ipath);

            /* If appropriate, consider parallel index scan */
            if (index->amcanparallel &&
                rel->consider_parallel && outer_relids == NULL &&
                scantype != ST_BITMAPSCAN)
            {
                ipath = create_index_path(root, index,
                                          index_clauses,
                                          NIL,
                                          NIL,
                                          useful_pathkeys,
                                          BackwardScanDirection,
                                          index_only_scan,
                                          outer_relids,
                                          loop_count,
                                          true);

                /*
                 * if, after costing the path, we find that it's not worth
                 * using parallel workers, just free it.
                 */
                if (ipath->path.parallel_workers > 0)
                    add_partial_path(rel, (Path *) ipath);
                else
                    pfree(ipath);
            }
        }
    }

    return result;
}

build_paths_for_OR()

static List * build_paths_for_OR ( PlannerInfo *  root, RelOptInfo *  rel, List *  clauses, List *  other_clauses  )

static

Definition at line 1166 of file indxpath.c.

References IndexOptInfo::amhasgetbitmap, build_index_paths(), RelOptInfo::indexlist, IndexOptInfo::indpred, lfirst, list_concat(), list_concat_copy(), match_clauses_to_index(), MemSet, NIL, IndexClauseSet::nonempty, predicate_implied_by(), IndexOptInfo::predOK, and ST_BITMAPSCAN.

Referenced by generate_bitmap_or_paths().

{
    List       *result = NIL;
    List       *all_clauses = NIL;  /* not computed till needed */
    ListCell   *lc;

    foreach(lc, rel->indexlist)
    {
        IndexOptInfo *index = (IndexOptInfo *) lfirst(lc);
        IndexClauseSet clauseset;
        List       *indexpaths;
        bool        useful_predicate;

        /* Ignore index if it doesn't support bitmap scans */
        if (!index->amhasgetbitmap)
            continue;

        /*
         * Ignore partial indexes that do not match the query.  If a partial
         * index is marked predOK then we know it's OK.  Otherwise, we have to
         * test whether the added clauses are sufficient to imply the
         * predicate. If so, we can use the index in the current context.
         *
         * We set useful_predicate to true iff the predicate was proven using
         * the current set of clauses.  This is needed to prevent matching a
         * predOK index to an arm of an OR, which would be a legal but
         * pointlessly inefficient plan.  (A better plan will be generated by
         * just scanning the predOK index alone, no OR.)
         */
        useful_predicate = false;
        if (index->indpred != NIL)
        {
            if (index->predOK)
            {
                /* Usable, but don't set useful_predicate */
            }
            else
            {
                /* Form all_clauses if not done already */
                if (all_clauses == NIL)
                    all_clauses = list_concat_copy(clauses, other_clauses);

                if (!predicate_implied_by(index->indpred, all_clauses, false))
                    continue;   /* can't use it at all */

                if (!predicate_implied_by(index->indpred, other_clauses, false))
                    useful_predicate = true;
            }
        }

        /*
         * Identify the restriction clauses that can match the index.
         */
        MemSet(&clauseset, 0, sizeof(clauseset));
        match_clauses_to_index(root, clauses, index, &clauseset);

        /*
         * If no matches so far, and the index predicate isn't useful, we
         * don't want it.
         */
        if (!clauseset.nonempty && !useful_predicate)
            continue;

        /*
         * Add "other" restriction clauses to the clauseset.
         */
        match_clauses_to_index(root, other_clauses, index, &clauseset);

        /*
         * Construct paths if possible.
         */
        indexpaths = build_index_paths(root, rel,
                                       index, &clauseset,
                                       useful_predicate,
                                       ST_BITMAPSCAN,
                                       NULL,
                                       NULL);
        result = list_concat(result, indexpaths);
    }

    return result;
}

check_index_only()

static bool check_index_only ( RelOptInfo *  rel, IndexOptInfo *  index  )

static

Definition at line 1888 of file indxpath.c.

References bms_add_member(), bms_del_members(), bms_free(), bms_is_subset(), IndexOptInfo::canreturn, RestrictInfo::clause, enable_indexonlyscan, PathTarget::exprs, FirstLowInvalidHeapAttributeNumber, i, IndexOptInfo::indexkeys, IndexOptInfo::indrestrictinfo, lfirst, IndexOptInfo::ncolumns, pull_varattnos(), RelOptInfo::relid, and RelOptInfo::reltarget.

Referenced by build_index_paths().

{
    bool        result;
    Bitmapset  *attrs_used = NULL;
    Bitmapset  *index_canreturn_attrs = NULL;
    Bitmapset  *index_cannotreturn_attrs = NULL;
    ListCell   *lc;
    int         i;

    /* Index-only scans must be enabled */
    if (!enable_indexonlyscan)
        return false;

    /*
     * Check that all needed attributes of the relation are available from the
     * index.
     */

    /*
     * First, identify all the attributes needed for joins or final output.
     * Note: we must look at rel's targetlist, not the attr_needed data,
     * because attr_needed isn't computed for inheritance child rels.
     */
    pull_varattnos((Node *) rel->reltarget->exprs, rel->relid, &attrs_used);

    /*
     * Add all the attributes used by restriction clauses; but consider only
     * those clauses not implied by the index predicate, since ones that are
     * so implied don't need to be checked explicitly in the plan.
     *
     * Note: attributes used only in index quals would not be needed at
     * runtime either, if we are certain that the index is not lossy.  However
     * it'd be complicated to account for that accurately, and it doesn't
     * matter in most cases, since we'd conclude that such attributes are
     * available from the index anyway.
     */
    foreach(lc, index->indrestrictinfo)
    {
        RestrictInfo *rinfo = (RestrictInfo *) lfirst(lc);

        pull_varattnos((Node *) rinfo->clause, rel->relid, &attrs_used);
    }

    /*
     * Construct a bitmapset of columns that the index can return back in an
     * index-only scan.  If there are multiple index columns containing the
     * same attribute, all of them must be capable of returning the value,
     * since we might recheck operators on any of them.  (Potentially we could
     * be smarter about that, but it's such a weird situation that it doesn't
     * seem worth spending a lot of sweat on.)
     */
    for (i = 0; i < index->ncolumns; i++)
    {
        int         attno = index->indexkeys[i];

        /*
         * For the moment, we just ignore index expressions.  It might be nice
         * to do something with them, later.
         */
        if (attno == 0)
            continue;

        if (index->canreturn[i])
            index_canreturn_attrs =
                bms_add_member(index_canreturn_attrs,
                               attno - FirstLowInvalidHeapAttributeNumber);
        else
            index_cannotreturn_attrs =
                bms_add_member(index_cannotreturn_attrs,
                               attno - FirstLowInvalidHeapAttributeNumber);
    }

    index_canreturn_attrs = bms_del_members(index_canreturn_attrs,
                                            index_cannotreturn_attrs);

    /* Do we have all the necessary attributes? */
    result = bms_is_subset(attrs_used, index_canreturn_attrs);

    bms_free(attrs_used);
    bms_free(index_canreturn_attrs);
    bms_free(index_cannotreturn_attrs);

    return result;
}

check_index_predicates()

void check_index_predicates	(	PlannerInfo *	root,
		RelOptInfo *	rel
	)

Definition at line 3395 of file indxpath.c.

References PlannerInfo::all_baserels, Assert, RelOptInfo::baserestrictinfo, bms_difference(), bms_is_empty(), bms_union(), RestrictInfo::clause, contain_mutable_functions(), find_childrel_parents(), generate_join_implied_equalities(), get_plan_rowmark(), RelOptInfo::indexlist, IndexOptInfo::indpred, IndexOptInfo::indrestrictinfo, IS_SIMPLE_REL, join_clause_is_movable_to(), RelOptInfo::joininfo, lappend(), lfirst, list_concat(), list_copy(), list_make1, NIL, PlannerInfo::parse, predicate_implied_by(), IndexOptInfo::predOK, RelOptInfo::relid, RelOptInfo::relids, RELOPT_OTHER_MEMBER_REL, RelOptInfo::reloptkind, Query::resultRelation, and PlannerInfo::rowMarks.

Referenced by set_plain_rel_size(), and set_tablesample_rel_size().

{
    List       *clauselist;
    bool        have_partial;
    bool        is_target_rel;
    Relids      otherrels;
    ListCell   *lc;

    /* Indexes are available only on base or "other" member relations. */
    Assert(IS_SIMPLE_REL(rel));

    /*
     * Initialize the indrestrictinfo lists to be identical to
     * baserestrictinfo, and check whether there are any partial indexes.  If
     * not, this is all we need to do.
     */
    have_partial = false;
    foreach(lc, rel->indexlist)
    {
        IndexOptInfo *index = (IndexOptInfo *) lfirst(lc);

        index->indrestrictinfo = rel->baserestrictinfo;
        if (index->indpred)
            have_partial = true;
    }
    if (!have_partial)
        return;

    /*
     * Construct a list of clauses that we can assume true for the purpose of
     * proving the index(es) usable.  Restriction clauses for the rel are
     * always usable, and so are any join clauses that are "movable to" this
     * rel.  Also, we can consider any EC-derivable join clauses (which must
     * be "movable to" this rel, by definition).
     */
    clauselist = list_copy(rel->baserestrictinfo);

    /* Scan the rel's join clauses */
    foreach(lc, rel->joininfo)
    {
        RestrictInfo *rinfo = (RestrictInfo *) lfirst(lc);

        /* Check if clause can be moved to this rel */
        if (!join_clause_is_movable_to(rinfo, rel))
            continue;

        clauselist = lappend(clauselist, rinfo);
    }

    /*
     * Add on any equivalence-derivable join clauses.  Computing the correct
     * relid sets for generate_join_implied_equalities is slightly tricky
     * because the rel could be a child rel rather than a true baserel, and in
     * that case we must remove its parents' relid(s) from all_baserels.
     */
    if (rel->reloptkind == RELOPT_OTHER_MEMBER_REL)
        otherrels = bms_difference(root->all_baserels,
                                   find_childrel_parents(root, rel));
    else
        otherrels = bms_difference(root->all_baserels, rel->relids);

    if (!bms_is_empty(otherrels))
        clauselist =
            list_concat(clauselist,
                        generate_join_implied_equalities(root,
                                                         bms_union(rel->relids,
                                                                   otherrels),
                                                         otherrels,
                                                         rel));

    /*
     * Normally we remove quals that are implied by a partial index's
     * predicate from indrestrictinfo, indicating that they need not be
     * checked explicitly by an indexscan plan using this index.  However, if
     * the rel is a target relation of UPDATE/DELETE/SELECT FOR UPDATE, we
     * cannot remove such quals from the plan, because they need to be in the
     * plan so that they will be properly rechecked by EvalPlanQual testing.
     * Some day we might want to remove such quals from the main plan anyway
     * and pass them through to EvalPlanQual via a side channel; but for now,
     * we just don't remove implied quals at all for target relations.
     */
    is_target_rel = (rel->relid == root->parse->resultRelation ||
                     get_plan_rowmark(root->rowMarks, rel->relid) != NULL);

    /*
     * Now try to prove each index predicate true, and compute the
     * indrestrictinfo lists for partial indexes.  Note that we compute the
     * indrestrictinfo list even for non-predOK indexes; this might seem
     * wasteful, but we may be able to use such indexes in OR clauses, cf
     * generate_bitmap_or_paths().
     */
    foreach(lc, rel->indexlist)
    {
        IndexOptInfo *index = (IndexOptInfo *) lfirst(lc);
        ListCell   *lcr;

        if (index->indpred == NIL)
            continue;           /* ignore non-partial indexes here */

        if (!index->predOK)     /* don't repeat work if already proven OK */
            index->predOK = predicate_implied_by(index->indpred, clauselist,
                                                 false);

        /* If rel is an update target, leave indrestrictinfo as set above */
        if (is_target_rel)
            continue;

        /* Else compute indrestrictinfo as the non-implied quals */
        index->indrestrictinfo = NIL;
        foreach(lcr, rel->baserestrictinfo)
        {
            RestrictInfo *rinfo = (RestrictInfo *) lfirst(lcr);

            /* predicate_implied_by() assumes first arg is immutable */
            if (contain_mutable_functions((Node *) rinfo->clause) ||
                !predicate_implied_by(list_make1(rinfo->clause),
                                      index->indpred, false))
                index->indrestrictinfo = lappend(index->indrestrictinfo, rinfo);
        }
    }
}

choose_bitmap_and()

static Path * choose_bitmap_and ( PlannerInfo *  root, RelOptInfo *  rel, List *  paths  )

static

Definition at line 1368 of file indxpath.c.

References Assert, bitmap_and_cost_est(), bitmap_scan_cost_est(), bms_add_members(), bms_copy(), bms_equal(), bms_overlap(), classify_index_clause_usage(), PathClauseUsage::clauseids, cost_bitmap_tree_node(), create_bitmap_and_path(), i, lappend(), lfirst, linitial, list_concat(), list_concat_copy(), list_free(), list_length(), list_make1, list_truncate(), NIL, palloc(), PathClauseUsage::path, path_usage_comparator(), predicate_implied_by(), PathClauseUsage::preds, qsort, PathClauseUsage::quals, and PathClauseUsage::unclassifiable.

Referenced by create_index_paths(), and generate_bitmap_or_paths().

{
    int         npaths = list_length(paths);
    PathClauseUsage **pathinfoarray;
    PathClauseUsage *pathinfo;
    List       *clauselist;
    List       *bestpaths = NIL;
    Cost        bestcost = 0;
    int         i,
                j;
    ListCell   *l;

    Assert(npaths > 0);         /* else caller error */
    if (npaths == 1)
        return (Path *) linitial(paths);    /* easy case */

    /*
     * In theory we should consider every nonempty subset of the given paths.
     * In practice that seems like overkill, given the crude nature of the
     * estimates, not to mention the possible effects of higher-level AND and
     * OR clauses.  Moreover, it's completely impractical if there are a large
     * number of paths, since the work would grow as O(2^N).
     *
     * As a heuristic, we first check for paths using exactly the same sets of
     * WHERE clauses + index predicate conditions, and reject all but the
     * cheapest-to-scan in any such group.  This primarily gets rid of indexes
     * that include the interesting columns but also irrelevant columns.  (In
     * situations where the DBA has gone overboard on creating variant
     * indexes, this can make for a very large reduction in the number of
     * paths considered further.)
     *
     * We then sort the surviving paths with the cheapest-to-scan first, and
     * for each path, consider using that path alone as the basis for a bitmap
     * scan.  Then we consider bitmap AND scans formed from that path plus
     * each subsequent (higher-cost) path, adding on a subsequent path if it
     * results in a reduction in the estimated total scan cost. This means we
     * consider about O(N^2) rather than O(2^N) path combinations, which is
     * quite tolerable, especially given than N is usually reasonably small
     * because of the prefiltering step.  The cheapest of these is returned.
     *
     * We will only consider AND combinations in which no two indexes use the
     * same WHERE clause.  This is a bit of a kluge: it's needed because
     * costsize.c and clausesel.c aren't very smart about redundant clauses.
     * They will usually double-count the redundant clauses, producing a
     * too-small selectivity that makes a redundant AND step look like it
     * reduces the total cost.  Perhaps someday that code will be smarter and
     * we can remove this limitation.  (But note that this also defends
     * against flat-out duplicate input paths, which can happen because
     * match_join_clauses_to_index will find the same OR join clauses that
     * extract_restriction_or_clauses has pulled OR restriction clauses out
     * of.)
     *
     * For the same reason, we reject AND combinations in which an index
     * predicate clause duplicates another clause.  Here we find it necessary
     * to be even stricter: we'll reject a partial index if any of its
     * predicate clauses are implied by the set of WHERE clauses and predicate
     * clauses used so far.  This covers cases such as a condition "x = 42"
     * used with a plain index, followed by a clauseless scan of a partial
     * index "WHERE x >= 40 AND x < 50".  The partial index has been accepted
     * only because "x = 42" was present, and so allowing it would partially
     * double-count selectivity.  (We could use predicate_implied_by on
     * regular qual clauses too, to have a more intelligent, but much more
     * expensive, check for redundancy --- but in most cases simple equality
     * seems to suffice.)
     */

    /*
     * Extract clause usage info and detect any paths that use exactly the
     * same set of clauses; keep only the cheapest-to-scan of any such groups.
     * The surviving paths are put into an array for qsort'ing.
     */
    pathinfoarray = (PathClauseUsage **)
        palloc(npaths * sizeof(PathClauseUsage *));
    clauselist = NIL;
    npaths = 0;
    foreach(l, paths)
    {
        Path       *ipath = (Path *) lfirst(l);

        pathinfo = classify_index_clause_usage(ipath, &clauselist);

        /* If it's unclassifiable, treat it as distinct from all others */
        if (pathinfo->unclassifiable)
        {
            pathinfoarray[npaths++] = pathinfo;
            continue;
        }

        for (i = 0; i < npaths; i++)
        {
            if (!pathinfoarray[i]->unclassifiable &&
                bms_equal(pathinfo->clauseids, pathinfoarray[i]->clauseids))
                break;
        }
        if (i < npaths)
        {
            /* duplicate clauseids, keep the cheaper one */
            Cost        ncost;
            Cost        ocost;
            Selectivity nselec;
            Selectivity oselec;

            cost_bitmap_tree_node(pathinfo->path, &ncost, &nselec);
            cost_bitmap_tree_node(pathinfoarray[i]->path, &ocost, &oselec);
            if (ncost < ocost)
                pathinfoarray[i] = pathinfo;
        }
        else
        {
            /* not duplicate clauseids, add to array */
            pathinfoarray[npaths++] = pathinfo;
        }
    }

    /* If only one surviving path, we're done */
    if (npaths == 1)
        return pathinfoarray[0]->path;

    /* Sort the surviving paths by index access cost */
    qsort(pathinfoarray, npaths, sizeof(PathClauseUsage *),
          path_usage_comparator);

    /*
     * For each surviving index, consider it as an "AND group leader", and see
     * whether adding on any of the later indexes results in an AND path with
     * cheaper total cost than before.  Then take the cheapest AND group.
     *
     * Note: paths that are either clauseless or unclassifiable will have
     * empty clauseids, so that they will not be rejected by the clauseids
     * filter here, nor will they cause later paths to be rejected by it.
     */
    for (i = 0; i < npaths; i++)
    {
        Cost        costsofar;
        List       *qualsofar;
        Bitmapset  *clauseidsofar;

        pathinfo = pathinfoarray[i];
        paths = list_make1(pathinfo->path);
        costsofar = bitmap_scan_cost_est(root, rel, pathinfo->path);
        qualsofar = list_concat_copy(pathinfo->quals, pathinfo->preds);
        clauseidsofar = bms_copy(pathinfo->clauseids);

        for (j = i + 1; j < npaths; j++)
        {
            Cost        newcost;

            pathinfo = pathinfoarray[j];
            /* Check for redundancy */
            if (bms_overlap(pathinfo->clauseids, clauseidsofar))
                continue;       /* consider it redundant */
            if (pathinfo->preds)
            {
                bool        redundant = false;

                /* we check each predicate clause separately */
                foreach(l, pathinfo->preds)
                {
                    Node       *np = (Node *) lfirst(l);

                    if (predicate_implied_by(list_make1(np), qualsofar, false))
                    {
                        redundant = true;
                        break;  /* out of inner foreach loop */
                    }
                }
                if (redundant)
                    continue;
            }
            /* tentatively add new path to paths, so we can estimate cost */
            paths = lappend(paths, pathinfo->path);
            newcost = bitmap_and_cost_est(root, rel, paths);
            if (newcost < costsofar)
            {
                /* keep new path in paths, update subsidiary variables */
                costsofar = newcost;
                qualsofar = list_concat(qualsofar, pathinfo->quals);
                qualsofar = list_concat(qualsofar, pathinfo->preds);
                clauseidsofar = bms_add_members(clauseidsofar,
                                                pathinfo->clauseids);
            }
            else
            {
                /* reject new path, remove it from paths list */
                paths = list_truncate(paths, list_length(paths) - 1);
            }
        }

        /* Keep the cheapest AND-group (or singleton) */
        if (i == 0 || costsofar < bestcost)
        {
            bestpaths = paths;
            bestcost = costsofar;
        }

        /* some easy cleanup (we don't try real hard though) */
        list_free(qualsofar);
    }

    if (list_length(bestpaths) == 1)
        return (Path *) linitial(bestpaths);    /* no need for AND */
    return (Path *) create_bitmap_and_path(root, rel, bestpaths);
}

classify_index_clause_usage()

static PathClauseUsage * classify_index_clause_usage ( Path *  path, List **  clauselist  )

static

Definition at line 1704 of file indxpath.c.

References bms_add_member(), PathClauseUsage::clauseids, find_indexpath_quals(), find_list_position(), lfirst, list_length(), NIL, palloc(), PathClauseUsage::path, PathClauseUsage::preds, PathClauseUsage::quals, and PathClauseUsage::unclassifiable.

Referenced by choose_bitmap_and().

{
    PathClauseUsage *result;
    Bitmapset  *clauseids;
    ListCell   *lc;

    result = (PathClauseUsage *) palloc(sizeof(PathClauseUsage));
    result->path = path;

    /* Recursively find the quals and preds used by the path */
    result->quals = NIL;
    result->preds = NIL;
    find_indexpath_quals(path, &result->quals, &result->preds);

    /*
     * Some machine-generated queries have outlandish numbers of qual clauses.
     * To avoid getting into O(N^2) behavior even in this preliminary
     * classification step, we want to limit the number of entries we can
     * accumulate in *clauselist.  Treat any path with more than 100 quals +
     * preds as unclassifiable, which will cause calling code to consider it
     * distinct from all other paths.
     */
    if (list_length(result->quals) + list_length(result->preds) > 100)
    {
        result->clauseids = NULL;
        result->unclassifiable = true;
        return result;
    }

    /* Build up a bitmapset representing the quals and preds */
    clauseids = NULL;
    foreach(lc, result->quals)
    {
        Node       *node = (Node *) lfirst(lc);

        clauseids = bms_add_member(clauseids,
                                   find_list_position(node, clauselist));
    }
    foreach(lc, result->preds)
    {
        Node       *node = (Node *) lfirst(lc);

        clauseids = bms_add_member(clauseids,
                                   find_list_position(node, clauselist));
    }
    result->clauseids = clauseids;
    result->unclassifiable = false;

    return result;
}

consider_index_join_clauses()

static void consider_index_join_clauses ( PlannerInfo *  root, RelOptInfo *  rel, IndexOptInfo *  index, IndexClauseSet *  rclauseset, IndexClauseSet *  jclauseset, IndexClauseSet *  eclauseset, List **  bitindexpaths  )

static

Definition at line 439 of file indxpath.c.

References consider_index_join_outer_rels(), IndexClauseSet::indexclauses, list_length(), NIL, and IndexOptInfo::nkeycolumns.

Referenced by create_index_paths().

{
    int         considered_clauses = 0;
    List       *considered_relids = NIL;
    int         indexcol;

    /*
     * The strategy here is to identify every potentially useful set of outer
     * rels that can provide indexable join clauses.  For each such set,
     * select all the join clauses available from those outer rels, add on all
     * the indexable restriction clauses, and generate plain and/or bitmap
     * index paths for that set of clauses.  This is based on the assumption
     * that it's always better to apply a clause as an indexqual than as a
     * filter (qpqual); which is where an available clause would end up being
     * applied if we omit it from the indexquals.
     *
     * This looks expensive, but in most practical cases there won't be very
     * many distinct sets of outer rels to consider.  As a safety valve when
     * that's not true, we use a heuristic: limit the number of outer rel sets
     * considered to a multiple of the number of clauses considered.  (We'll
     * always consider using each individual join clause, though.)
     *
     * For simplicity in selecting relevant clauses, we represent each set of
     * outer rels as a maximum set of clause_relids --- that is, the indexed
     * relation itself is also included in the relids set.  considered_relids
     * lists all relids sets we've already tried.
     */
    for (indexcol = 0; indexcol < index->nkeycolumns; indexcol++)
    {
        /* Consider each applicable simple join clause */
        considered_clauses += list_length(jclauseset->indexclauses[indexcol]);
        consider_index_join_outer_rels(root, rel, index,
                                       rclauseset, jclauseset, eclauseset,
                                       bitindexpaths,
                                       jclauseset->indexclauses[indexcol],
                                       considered_clauses,
                                       &considered_relids);
        /* Consider each applicable eclass join clause */
        considered_clauses += list_length(eclauseset->indexclauses[indexcol]);
        consider_index_join_outer_rels(root, rel, index,
                                       rclauseset, jclauseset, eclauseset,
                                       bitindexpaths,
                                       eclauseset->indexclauses[indexcol],
                                       considered_clauses,
                                       &considered_relids);
    }
}

consider_index_join_outer_rels()

static void consider_index_join_outer_rels ( PlannerInfo *  root, RelOptInfo *  rel, IndexOptInfo *  index, IndexClauseSet *  rclauseset, IndexClauseSet *  jclauseset, IndexClauseSet *  eclauseset, List **  bitindexpaths, List *  indexjoinclauses, int  considered_clauses, List **  considered_relids  )

static

Definition at line 505 of file indxpath.c.

References BMS_DIFFERENT, bms_equal_any(), bms_subset_compare(), bms_union(), RestrictInfo::clause_relids, eclass_already_used(), get_join_index_paths(), lfirst, list_length(), list_nth(), RestrictInfo::parent_ec, and IndexClause::rinfo.

Referenced by consider_index_join_clauses().

{
    ListCell   *lc;

    /* Examine relids of each joinclause in the given list */
    foreach(lc, indexjoinclauses)
    {
        IndexClause *iclause = (IndexClause *) lfirst(lc);
        Relids      clause_relids = iclause->rinfo->clause_relids;
        EquivalenceClass *parent_ec = iclause->rinfo->parent_ec;
        int         num_considered_relids;

        /* If we already tried its relids set, no need to do so again */
        if (bms_equal_any(clause_relids, *considered_relids))
            continue;

        /*
         * Generate the union of this clause's relids set with each
         * previously-tried set.  This ensures we try this clause along with
         * every interesting subset of previous clauses.  However, to avoid
         * exponential growth of planning time when there are many clauses,
         * limit the number of relid sets accepted to 10 * considered_clauses.
         *
         * Note: get_join_index_paths appends entries to *considered_relids,
         * but we do not need to visit such newly-added entries within this
         * loop, so we don't use foreach() here.  No real harm would be done
         * if we did visit them, since the subset check would reject them; but
         * it would waste some cycles.
         */
        num_considered_relids = list_length(*considered_relids);
        for (int pos = 0; pos < num_considered_relids; pos++)
        {
            Relids      oldrelids = (Relids) list_nth(*considered_relids, pos);

            /*
             * If either is a subset of the other, no new set is possible.
             * This isn't a complete test for redundancy, but it's easy and
             * cheap.  get_join_index_paths will check more carefully if we
             * already generated the same relids set.
             */
            if (bms_subset_compare(clause_relids, oldrelids) != BMS_DIFFERENT)
                continue;

            /*
             * If this clause was derived from an equivalence class, the
             * clause list may contain other clauses derived from the same
             * eclass.  We should not consider that combining this clause with
             * one of those clauses generates a usefully different
             * parameterization; so skip if any clause derived from the same
             * eclass would already have been included when using oldrelids.
             */
            if (parent_ec &&
                eclass_already_used(parent_ec, oldrelids,
                                    indexjoinclauses))
                continue;

            /*
             * If the number of relid sets considered exceeds our heuristic
             * limit, stop considering combinations of clauses.  We'll still
             * consider the current clause alone, though (below this loop).
             */
            if (list_length(*considered_relids) >= 10 * considered_clauses)
                break;

            /* OK, try the union set */
            get_join_index_paths(root, rel, index,
                                 rclauseset, jclauseset, eclauseset,
                                 bitindexpaths,
                                 bms_union(clause_relids, oldrelids),
                                 considered_relids);
        }

        /* Also try this set of relids by itself */
        get_join_index_paths(root, rel, index,
                             rclauseset, jclauseset, eclauseset,
                             bitindexpaths,
                             clause_relids,
                             considered_relids);
    }
}

create_index_paths()

void create_index_paths	(	PlannerInfo *	root,
		RelOptInfo *	rel
	)

Definition at line 232 of file indxpath.c.

References add_path(), Assert, RelOptInfo::baserestrictinfo, bms_equal_any(), bms_is_subset(), choose_bitmap_and(), consider_index_join_clauses(), RelOptInfo::consider_parallel, create_bitmap_heap_path(), create_partial_bitmap_paths(), forboth, generate_bitmap_or_paths(), get_bitmap_tree_required_outer(), get_index_paths(), get_loop_count(), INDEX_MAX_KEYS, RelOptInfo::indexlist, IndexOptInfo::indpred, lappend(), RelOptInfo::lateral_relids, lfirst, list_concat(), match_eclass_clauses_to_index(), match_join_clauses_to_index(), match_restriction_clauses_to_index(), MemSet, NIL, IndexOptInfo::nkeycolumns, IndexClauseSet::nonempty, IndexOptInfo::predOK, and RelOptInfo::relid.

Referenced by set_plain_rel_pathlist().

{
    List       *indexpaths;
    List       *bitindexpaths;
    List       *bitjoinpaths;
    List       *joinorclauses;
    IndexClauseSet rclauseset;
    IndexClauseSet jclauseset;
    IndexClauseSet eclauseset;
    ListCell   *lc;

    /* Skip the whole mess if no indexes */
    if (rel->indexlist == NIL)
        return;

    /* Bitmap paths are collected and then dealt with at the end */
    bitindexpaths = bitjoinpaths = joinorclauses = NIL;

    /* Examine each index in turn */
    foreach(lc, rel->indexlist)
    {
        IndexOptInfo *index = (IndexOptInfo *) lfirst(lc);

        /* Protect limited-size array in IndexClauseSets */
        Assert(index->nkeycolumns <= INDEX_MAX_KEYS);

        /*
         * Ignore partial indexes that do not match the query.
         * (generate_bitmap_or_paths() might be able to do something with
         * them, but that's of no concern here.)
         */
        if (index->indpred != NIL && !index->predOK)
            continue;

        /*
         * Identify the restriction clauses that can match the index.
         */
        MemSet(&rclauseset, 0, sizeof(rclauseset));
        match_restriction_clauses_to_index(root, index, &rclauseset);

        /*
         * Build index paths from the restriction clauses.  These will be
         * non-parameterized paths.  Plain paths go directly to add_path(),
         * bitmap paths are added to bitindexpaths to be handled below.
         */
        get_index_paths(root, rel, index, &rclauseset,
                        &bitindexpaths);

        /*
         * Identify the join clauses that can match the index.  For the moment
         * we keep them separate from the restriction clauses.  Note that this
         * step finds only "loose" join clauses that have not been merged into
         * EquivalenceClasses.  Also, collect join OR clauses for later.
         */
        MemSet(&jclauseset, 0, sizeof(jclauseset));
        match_join_clauses_to_index(root, rel, index,
                                    &jclauseset, &joinorclauses);

        /*
         * Look for EquivalenceClasses that can generate joinclauses matching
         * the index.
         */
        MemSet(&eclauseset, 0, sizeof(eclauseset));
        match_eclass_clauses_to_index(root, index,
                                      &eclauseset);

        /*
         * If we found any plain or eclass join clauses, build parameterized
         * index paths using them.
         */
        if (jclauseset.nonempty || eclauseset.nonempty)
            consider_index_join_clauses(root, rel, index,
                                        &rclauseset,
                                        &jclauseset,
                                        &eclauseset,
                                        &bitjoinpaths);
    }

    /*
     * Generate BitmapOrPaths for any suitable OR-clauses present in the
     * restriction list.  Add these to bitindexpaths.
     */
    indexpaths = generate_bitmap_or_paths(root, rel,
                                          rel->baserestrictinfo, NIL);
    bitindexpaths = list_concat(bitindexpaths, indexpaths);

    /*
     * Likewise, generate BitmapOrPaths for any suitable OR-clauses present in
     * the joinclause list.  Add these to bitjoinpaths.
     */
    indexpaths = generate_bitmap_or_paths(root, rel,
                                          joinorclauses, rel->baserestrictinfo);
    bitjoinpaths = list_concat(bitjoinpaths, indexpaths);

    /*
     * If we found anything usable, generate a BitmapHeapPath for the most
     * promising combination of restriction bitmap index paths.  Note there
     * will be only one such path no matter how many indexes exist.  This
     * should be sufficient since there's basically only one figure of merit
     * (total cost) for such a path.
     */
    if (bitindexpaths != NIL)
    {
        Path       *bitmapqual;
        BitmapHeapPath *bpath;

        bitmapqual = choose_bitmap_and(root, rel, bitindexpaths);
        bpath = create_bitmap_heap_path(root, rel, bitmapqual,
                                        rel->lateral_relids, 1.0, 0);
        add_path(rel, (Path *) bpath);

        /* create a partial bitmap heap path */
        if (rel->consider_parallel && rel->lateral_relids == NULL)
            create_partial_bitmap_paths(root, rel, bitmapqual);
    }

    /*
     * Likewise, if we found anything usable, generate BitmapHeapPaths for the
     * most promising combinations of join bitmap index paths.  Our strategy
     * is to generate one such path for each distinct parameterization seen
     * among the available bitmap index paths.  This may look pretty
     * expensive, but usually there won't be very many distinct
     * parameterizations.  (This logic is quite similar to that in
     * consider_index_join_clauses, but we're working with whole paths not
     * individual clauses.)
     */
    if (bitjoinpaths != NIL)
    {
        List       *path_outer;
        List       *all_path_outers;
        ListCell   *lc;

        /*
         * path_outer holds the parameterization of each path in bitjoinpaths
         * (to save recalculating that several times), while all_path_outers
         * holds all distinct parameterization sets.
         */
        path_outer = all_path_outers = NIL;
        foreach(lc, bitjoinpaths)
        {
            Path       *path = (Path *) lfirst(lc);
            Relids      required_outer;

            required_outer = get_bitmap_tree_required_outer(path);
            path_outer = lappend(path_outer, required_outer);
            if (!bms_equal_any(required_outer, all_path_outers))
                all_path_outers = lappend(all_path_outers, required_outer);
        }

        /* Now, for each distinct parameterization set ... */
        foreach(lc, all_path_outers)
        {
            Relids      max_outers = (Relids) lfirst(lc);
            List       *this_path_set;
            Path       *bitmapqual;
            Relids      required_outer;
            double      loop_count;
            BitmapHeapPath *bpath;
            ListCell   *lcp;
            ListCell   *lco;

            /* Identify all the bitmap join paths needing no more than that */
            this_path_set = NIL;
            forboth(lcp, bitjoinpaths, lco, path_outer)
            {
                Path       *path = (Path *) lfirst(lcp);
                Relids      p_outers = (Relids) lfirst(lco);

                if (bms_is_subset(p_outers, max_outers))
                    this_path_set = lappend(this_path_set, path);
            }

            /*
             * Add in restriction bitmap paths, since they can be used
             * together with any join paths.
             */
            this_path_set = list_concat(this_path_set, bitindexpaths);

            /* Select best AND combination for this parameterization */
            bitmapqual = choose_bitmap_and(root, rel, this_path_set);

            /* And push that path into the mix */
            required_outer = get_bitmap_tree_required_outer(bitmapqual);
            loop_count = get_loop_count(root, rel->relid, required_outer);
            bpath = create_bitmap_heap_path(root, rel, bitmapqual,
                                            required_outer, loop_count, 0);
            add_path(rel, (Path *) bpath);
        }
    }
}

ec_member_matches_indexcol()

static bool ec_member_matches_indexcol ( PlannerInfo *  root, RelOptInfo *  rel, EquivalenceClass *  ec, EquivalenceMember *  em, void *  arg  )

static

Definition at line 3528 of file indxpath.c.

References Assert, EquivalenceClass::ec_collation, EquivalenceClass::ec_opfamilies, EquivalenceMember::em_expr, IndexOptInfo::indexcollations, IndexCollMatchesExprColl, list_member_oid(), match_index_to_operand(), IndexOptInfo::opfamily, and IndexOptInfo::relam.

Referenced by match_eclass_clauses_to_index().

{
    IndexOptInfo *index = ((ec_member_matches_arg *) arg)->index;
    int         indexcol = ((ec_member_matches_arg *) arg)->indexcol;
    Oid         curFamily;
    Oid         curCollation;

    Assert(indexcol < index->nkeycolumns);

    curFamily = index->opfamily[indexcol];
    curCollation = index->indexcollations[indexcol];

    /*
     * If it's a btree index, we can reject it if its opfamily isn't
     * compatible with the EC, since no clause generated from the EC could be
     * used with the index.  For non-btree indexes, we can't easily tell
     * whether clauses generated from the EC could be used with the index, so
     * don't check the opfamily.  This might mean we return "true" for a
     * useless EC, so we have to recheck the results of
     * generate_implied_equalities_for_column; see
     * match_eclass_clauses_to_index.
     */
    if (index->relam == BTREE_AM_OID &&
        !list_member_oid(ec->ec_opfamilies, curFamily))
        return false;

    /* We insist on collation match for all index types, though */
    if (!IndexCollMatchesExprColl(curCollation, ec->ec_collation))
        return false;

    return match_index_to_operand((Node *) em->em_expr, indexcol, index);
}

eclass_already_used()

static bool eclass_already_used ( EquivalenceClass *  parent_ec, Relids  oldrelids, List *  indexjoinclauses  )

static

Definition at line 686 of file indxpath.c.

References bms_is_subset(), RestrictInfo::clause_relids, lfirst, RestrictInfo::parent_ec, and IndexClause::rinfo.

Referenced by consider_index_join_outer_rels().

{
    ListCell   *lc;

    foreach(lc, indexjoinclauses)
    {
        IndexClause *iclause = (IndexClause *) lfirst(lc);
        RestrictInfo *rinfo = iclause->rinfo;

        if (rinfo->parent_ec == parent_ec &&
            bms_is_subset(rinfo->clause_relids, oldrelids))
            return true;
    }
    return false;
}

expand_indexqual_rowcompare()

static IndexClause * expand_indexqual_rowcompare ( RestrictInfo *  rinfo, int  indexcol, IndexOptInfo *  index, Oid  expr_op, bool  var_on_left  )

static

Definition at line 2946 of file indxpath.c.

References bms_is_member(), BTGreaterEqualStrategyNumber, BTGreaterStrategyNumber, BTLessEqualStrategyNumber, BTLessStrategyNumber, RestrictInfo::clause, contain_volatile_functions(), copyObject, elog, ERROR, forthree, get_commutator(), get_op_opfamily_properties(), get_op_opfamily_strategy(), get_opfamily_member(), i, IndexClause::indexcol, IndexOptInfo::indexcollations, IndexCollMatchesExprColl, IndexClause::indexcols, IndexClause::indexquals, RowCompareExpr::inputcollids, InvalidOid, lappend_int(), lappend_oid(), RowCompareExpr::largs, lfirst_oid, linitial, linitial_oid, list_copy(), list_length(), list_make1, list_make1_int, list_make1_oid, list_nth(), list_nth_oid(), list_truncate(), IndexClause::lossy, make_opclause(), make_simple_restrictinfo, makeNode, match_index_to_operand(), NIL, IndexOptInfo::nkeycolumns, OidIsValid, RowCompareExpr::opfamilies, IndexOptInfo::opfamily, RowCompareExpr::opnos, pull_varnos(), RowCompareExpr::rargs, RowCompareExpr::rctype, IndexOptInfo::rel, RelOptInfo::relid, and IndexClause::rinfo.

Referenced by match_rowcompare_to_indexcol().

{
    IndexClause *iclause = makeNode(IndexClause);
    RowCompareExpr *clause = (RowCompareExpr *) rinfo->clause;
    int         op_strategy;
    Oid         op_lefttype;
    Oid         op_righttype;
    int         matching_cols;
    List       *expr_ops;
    List       *opfamilies;
    List       *lefttypes;
    List       *righttypes;
    List       *new_ops;
    List       *var_args;
    List       *non_var_args;

    iclause->rinfo = rinfo;
    iclause->indexcol = indexcol;

    if (var_on_left)
    {
        var_args = clause->largs;
        non_var_args = clause->rargs;
    }
    else
    {
        var_args = clause->rargs;
        non_var_args = clause->largs;
    }

    get_op_opfamily_properties(expr_op, index->opfamily[indexcol], false,
                               &op_strategy,
                               &op_lefttype,
                               &op_righttype);

    /* Initialize returned list of which index columns are used */
    iclause->indexcols = list_make1_int(indexcol);

    /* Build lists of ops, opfamilies and operator datatypes in case needed */
    expr_ops = list_make1_oid(expr_op);
    opfamilies = list_make1_oid(index->opfamily[indexcol]);
    lefttypes = list_make1_oid(op_lefttype);
    righttypes = list_make1_oid(op_righttype);

    /*
     * See how many of the remaining columns match some index column in the
     * same way.  As in match_clause_to_indexcol(), the "other" side of any
     * potential index condition is OK as long as it doesn't use Vars from the
     * indexed relation.
     */
    matching_cols = 1;

    while (matching_cols < list_length(var_args))
    {
        Node       *varop = (Node *) list_nth(var_args, matching_cols);
        Node       *constop = (Node *) list_nth(non_var_args, matching_cols);
        int         i;

        expr_op = list_nth_oid(clause->opnos, matching_cols);
        if (!var_on_left)
        {
            /* indexkey is on right, so commute the operator */
            expr_op = get_commutator(expr_op);
            if (expr_op == InvalidOid)
                break;          /* operator is not usable */
        }
        if (bms_is_member(index->rel->relid, pull_varnos(constop)))
            break;              /* no good, Var on wrong side */
        if (contain_volatile_functions(constop))
            break;              /* no good, volatile comparison value */

        /*
         * The Var side can match any key column of the index.
         */
        for (i = 0; i < index->nkeycolumns; i++)
        {
            if (match_index_to_operand(varop, i, index) &&
                get_op_opfamily_strategy(expr_op,
                                         index->opfamily[i]) == op_strategy &&
                IndexCollMatchesExprColl(index->indexcollations[i],
                                         list_nth_oid(clause->inputcollids,
                                                      matching_cols)))
                break;
        }
        if (i >= index->nkeycolumns)
            break;              /* no match found */

        /* Add column number to returned list */
        iclause->indexcols = lappend_int(iclause->indexcols, i);

        /* Add operator info to lists */
        get_op_opfamily_properties(expr_op, index->opfamily[i], false,
                                   &op_strategy,
                                   &op_lefttype,
                                   &op_righttype);
        expr_ops = lappend_oid(expr_ops, expr_op);
        opfamilies = lappend_oid(opfamilies, index->opfamily[i]);
        lefttypes = lappend_oid(lefttypes, op_lefttype);
        righttypes = lappend_oid(righttypes, op_righttype);

        /* This column matches, keep scanning */
        matching_cols++;
    }

    /* Result is non-lossy if all columns are usable as index quals */
    iclause->lossy = (matching_cols != list_length(clause->opnos));

    /*
     * We can use rinfo->clause as-is if we have var on left and it's all
     * usable as index quals.
     */
    if (var_on_left && !iclause->lossy)
        iclause->indexquals = list_make1(rinfo);
    else
    {
        /*
         * We have to generate a modified rowcompare (possibly just one
         * OpExpr).  The painful part of this is changing < to <= or > to >=,
         * so deal with that first.
         */
        if (!iclause->lossy)
        {
            /* very easy, just use the commuted operators */
            new_ops = expr_ops;
        }
        else if (op_strategy == BTLessEqualStrategyNumber ||
                 op_strategy == BTGreaterEqualStrategyNumber)
        {
            /* easy, just use the same (possibly commuted) operators */
            new_ops = list_truncate(expr_ops, matching_cols);
        }
        else
        {
            ListCell   *opfamilies_cell;
            ListCell   *lefttypes_cell;
            ListCell   *righttypes_cell;

            if (op_strategy == BTLessStrategyNumber)
                op_strategy = BTLessEqualStrategyNumber;
            else if (op_strategy == BTGreaterStrategyNumber)
                op_strategy = BTGreaterEqualStrategyNumber;
            else
                elog(ERROR, "unexpected strategy number %d", op_strategy);
            new_ops = NIL;
            forthree(opfamilies_cell, opfamilies,
                     lefttypes_cell, lefttypes,
                     righttypes_cell, righttypes)
            {
                Oid         opfam = lfirst_oid(opfamilies_cell);
                Oid         lefttype = lfirst_oid(lefttypes_cell);
                Oid         righttype = lfirst_oid(righttypes_cell);

                expr_op = get_opfamily_member(opfam, lefttype, righttype,
                                              op_strategy);
                if (!OidIsValid(expr_op))   /* should not happen */
                    elog(ERROR, "missing operator %d(%u,%u) in opfamily %u",
                         op_strategy, lefttype, righttype, opfam);
                new_ops = lappend_oid(new_ops, expr_op);
            }
        }

        /* If we have more than one matching col, create a subset rowcompare */
        if (matching_cols > 1)
        {
            RowCompareExpr *rc = makeNode(RowCompareExpr);

            rc->rctype = (RowCompareType) op_strategy;
            rc->opnos = new_ops;
            rc->opfamilies = list_truncate(list_copy(clause->opfamilies),
                                           matching_cols);
            rc->inputcollids = list_truncate(list_copy(clause->inputcollids),
                                             matching_cols);
            rc->largs = list_truncate(copyObject(var_args),
                                      matching_cols);
            rc->rargs = list_truncate(copyObject(non_var_args),
                                      matching_cols);
            iclause->indexquals = list_make1(make_simple_restrictinfo((Expr *) rc));
        }
        else
        {
            Expr       *op;

            /* We don't report an index column list in this case */
            iclause->indexcols = NIL;

            op = make_opclause(linitial_oid(new_ops), BOOLOID, false,
                               copyObject(linitial(var_args)),
                               copyObject(linitial(non_var_args)),
                               InvalidOid,
                               linitial_oid(clause->inputcollids));
            iclause->indexquals = list_make1(make_simple_restrictinfo(op));
        }
    }

    return iclause;
}

find_indexpath_quals()

static void find_indexpath_quals ( Path *  bitmapqual, List **  quals, List **  preds  )

static

Definition at line 1815 of file indxpath.c.

References BitmapAndPath::bitmapquals, BitmapOrPath::bitmapquals, RestrictInfo::clause, elog, ERROR, IndexPath::indexclauses, IndexPath::indexinfo, IndexOptInfo::indpred, IsA, lappend(), lfirst, list_concat(), nodeTag, and IndexClause::rinfo.

Referenced by classify_index_clause_usage().

{
    if (IsA(bitmapqual, BitmapAndPath))
    {
        BitmapAndPath *apath = (BitmapAndPath *) bitmapqual;
        ListCell   *l;

        foreach(l, apath->bitmapquals)
        {
            find_indexpath_quals((Path *) lfirst(l), quals, preds);
        }
    }
    else if (IsA(bitmapqual, BitmapOrPath))
    {
        BitmapOrPath *opath = (BitmapOrPath *) bitmapqual;
        ListCell   *l;

        foreach(l, opath->bitmapquals)
        {
            find_indexpath_quals((Path *) lfirst(l), quals, preds);
        }
    }
    else if (IsA(bitmapqual, IndexPath))
    {
        IndexPath  *ipath = (IndexPath *) bitmapqual;
        ListCell   *l;

        foreach(l, ipath->indexclauses)
        {
            IndexClause *iclause = (IndexClause *) lfirst(l);

            *quals = lappend(*quals, iclause->rinfo->clause);
        }
        *preds = list_concat(*preds, ipath->indexinfo->indpred);
    }
    else
        elog(ERROR, "unrecognized node type: %d", nodeTag(bitmapqual));
}

find_list_position()

static int find_list_position ( Node *  node, List **  nodelist  )

static

Definition at line 1862 of file indxpath.c.

References equal(), i, lappend(), and lfirst.

Referenced by classify_index_clause_usage().

{
    int         i;
    ListCell   *lc;

    i = 0;
    foreach(lc, *nodelist)
    {
        Node       *oldnode = (Node *) lfirst(lc);

        if (equal(node, oldnode))
            return i;
        i++;
    }

    *nodelist = lappend(*nodelist, node);

    return i;
}

generate_bitmap_or_paths()

static List * generate_bitmap_or_paths ( PlannerInfo *  root, RelOptInfo *  rel, List *  clauses, List *  other_clauses  )

static

Definition at line 1261 of file indxpath.c.

References Assert, build_paths_for_OR(), castNode, choose_bitmap_and(), create_bitmap_or_path(), is_andclause(), lappend(), lfirst, lfirst_node, list_concat(), list_concat_copy(), list_make1, NIL, RestrictInfo::orclause, and restriction_is_or_clause().

Referenced by create_index_paths().

{
    List       *result = NIL;
    List       *all_clauses;
    ListCell   *lc;

    /*
     * We can use both the current and other clauses as context for
     * build_paths_for_OR; no need to remove ORs from the lists.
     */
    all_clauses = list_concat_copy(clauses, other_clauses);

    foreach(lc, clauses)
    {
        RestrictInfo *rinfo = lfirst_node(RestrictInfo, lc);
        List       *pathlist;
        Path       *bitmapqual;
        ListCell   *j;

        /* Ignore RestrictInfos that aren't ORs */
        if (!restriction_is_or_clause(rinfo))
            continue;

        /*
         * We must be able to match at least one index to each of the arms of
         * the OR, else we can't use it.
         */
        pathlist = NIL;
        foreach(j, ((BoolExpr *) rinfo->orclause)->args)
        {
            Node       *orarg = (Node *) lfirst(j);
            List       *indlist;

            /* OR arguments should be ANDs or sub-RestrictInfos */
            if (is_andclause(orarg))
            {
                List       *andargs = ((BoolExpr *) orarg)->args;

                indlist = build_paths_for_OR(root, rel,
                                             andargs,
                                             all_clauses);

                /* Recurse in case there are sub-ORs */
                indlist = list_concat(indlist,
                                      generate_bitmap_or_paths(root, rel,
                                                               andargs,
                                                               all_clauses));
            }
            else
            {
                RestrictInfo *rinfo = castNode(RestrictInfo, orarg);
                List       *orargs;

                Assert(!restriction_is_or_clause(rinfo));
                orargs = list_make1(rinfo);

                indlist = build_paths_for_OR(root, rel,
                                             orargs,
                                             all_clauses);
            }

            /*
             * If nothing matched this arm, we can't do anything with this OR
             * clause.
             */
            if (indlist == NIL)
            {
                pathlist = NIL;
                break;
            }

            /*
             * OK, pick the most promising AND combination, and add it to
             * pathlist.
             */
            bitmapqual = choose_bitmap_and(root, rel, indlist);
            pathlist = lappend(pathlist, bitmapqual);
        }

        /*
         * If we have a match for every arm, then turn them into a
         * BitmapOrPath, and add to result list.
         */
        if (pathlist != NIL)
        {
            bitmapqual = (Path *) create_bitmap_or_path(root, rel, pathlist);
            result = lappend(result, bitmapqual);
        }
    }

    return result;
}

get_bitmap_tree_required_outer()

static Relids get_bitmap_tree_required_outer ( Path *  bitmapqual )

static

Definition at line 1767 of file indxpath.c.

References bms_copy(), bms_join(), elog, ERROR, IsA, lfirst, nodeTag, and PATH_REQ_OUTER.

Referenced by bitmap_and_cost_est(), bitmap_scan_cost_est(), and create_index_paths().

{
    Relids      result = NULL;
    ListCell   *lc;

    if (IsA(bitmapqual, IndexPath))
    {
        return bms_copy(PATH_REQ_OUTER(bitmapqual));
    }
    else if (IsA(bitmapqual, BitmapAndPath))
    {
        foreach(lc, ((BitmapAndPath *) bitmapqual)->bitmapquals)
        {
            result = bms_join(result,
                              get_bitmap_tree_required_outer((Path *) lfirst(lc)));
        }
    }
    else if (IsA(bitmapqual, BitmapOrPath))
    {
        foreach(lc, ((BitmapOrPath *) bitmapqual)->bitmapquals)
        {
            result = bms_join(result,
                              get_bitmap_tree_required_outer((Path *) lfirst(lc)));
        }
    }
    else
        elog(ERROR, "unrecognized node type: %d", nodeTag(bitmapqual));

    return result;
}

get_index_clause_from_support()

static IndexClause * get_index_clause_from_support ( PlannerInfo *  root, RestrictInfo *  rinfo, Oid  funcid, int  indexarg, int  indexcol, IndexOptInfo *  index  )

static

Definition at line 2709 of file indxpath.c.

References RestrictInfo::clause, DatumGetPointer, SupportRequestIndexCondition::funcid, get_func_support(), SupportRequestIndexCondition::index, SupportRequestIndexCondition::indexarg, SupportRequestIndexCondition::indexcol, IndexClause::indexcol, SupportRequestIndexCondition::indexcollation, IndexOptInfo::indexcollations, IndexClause::indexcols, IndexClause::indexquals, lappend(), lfirst, SupportRequestIndexCondition::lossy, IndexClause::lossy, make_simple_restrictinfo, makeNode, NIL, SupportRequestIndexCondition::node, OidFunctionCall1, OidIsValid, SupportRequestIndexCondition::opfamily, IndexOptInfo::opfamily, PointerGetDatum, IndexClause::rinfo, SupportRequestIndexCondition::root, T_SupportRequestIndexCondition, and SupportRequestIndexCondition::type.

Referenced by match_funcclause_to_indexcol(), and match_opclause_to_indexcol().

{
    Oid         prosupport = get_func_support(funcid);
    SupportRequestIndexCondition req;
    List       *sresult;

    if (!OidIsValid(prosupport))
        return NULL;

    req.type = T_SupportRequestIndexCondition;
    req.root = root;
    req.funcid = funcid;
    req.node = (Node *) rinfo->clause;
    req.indexarg = indexarg;
    req.index = index;
    req.indexcol = indexcol;
    req.opfamily = index->opfamily[indexcol];
    req.indexcollation = index->indexcollations[indexcol];

    req.lossy = true;           /* default assumption */

    sresult = (List *)
        DatumGetPointer(OidFunctionCall1(prosupport,
                                         PointerGetDatum(&req)));

    if (sresult != NIL)
    {
        IndexClause *iclause = makeNode(IndexClause);
        List       *indexquals = NIL;
        ListCell   *lc;

        /*
         * The support function API says it should just give back bare
         * clauses, so here we must wrap each one in a RestrictInfo.
         */
        foreach(lc, sresult)
        {
            Expr       *clause = (Expr *) lfirst(lc);

            indexquals = lappend(indexquals, make_simple_restrictinfo(clause));
        }

        iclause->rinfo = rinfo;
        iclause->indexquals = indexquals;
        iclause->lossy = req.lossy;
        iclause->indexcol = indexcol;
        iclause->indexcols = NIL;

        return iclause;
    }

    return NULL;
}

get_index_paths()

static void get_index_paths ( PlannerInfo *  root, RelOptInfo *  rel, IndexOptInfo *  index, IndexClauseSet *  clauses, List **  bitindexpaths  )

static

Definition at line 739 of file indxpath.c.

References add_path(), IndexOptInfo::amhasgetbitmap, IndexOptInfo::amhasgettuple, build_index_paths(), lappend(), lfirst, list_concat(), NIL, Path::pathkeys, IndexOptInfo::predOK, ST_ANYSCAN, and ST_BITMAPSCAN.

Referenced by create_index_paths(), and get_join_index_paths().

{
    List       *indexpaths;
    bool        skip_nonnative_saop = false;
    bool        skip_lower_saop = false;
    ListCell   *lc;

    /*
     * Build simple index paths using the clauses.  Allow ScalarArrayOpExpr
     * clauses only if the index AM supports them natively, and skip any such
     * clauses for index columns after the first (so that we produce ordered
     * paths if possible).
     */
    indexpaths = build_index_paths(root, rel,
                                   index, clauses,
                                   index->predOK,
                                   ST_ANYSCAN,
                                   &skip_nonnative_saop,
                                   &skip_lower_saop);

    /*
     * If we skipped any lower-order ScalarArrayOpExprs on an index with an AM
     * that supports them, then try again including those clauses.  This will
     * produce paths with more selectivity but no ordering.
     */
    if (skip_lower_saop)
    {
        indexpaths = list_concat(indexpaths,
                                 build_index_paths(root, rel,
                                                   index, clauses,
                                                   index->predOK,
                                                   ST_ANYSCAN,
                                                   &skip_nonnative_saop,
                                                   NULL));
    }

    /*
     * Submit all the ones that can form plain IndexScan plans to add_path. (A
     * plain IndexPath can represent either a plain IndexScan or an
     * IndexOnlyScan, but for our purposes here that distinction does not
     * matter.  However, some of the indexes might support only bitmap scans,
     * and those we mustn't submit to add_path here.)
     *
     * Also, pick out the ones that are usable as bitmap scans.  For that, we
     * must discard indexes that don't support bitmap scans, and we also are
     * only interested in paths that have some selectivity; we should discard
     * anything that was generated solely for ordering purposes.
     */
    foreach(lc, indexpaths)
    {
        IndexPath  *ipath = (IndexPath *) lfirst(lc);

        if (index->amhasgettuple)
            add_path(rel, (Path *) ipath);

        if (index->amhasgetbitmap &&
            (ipath->path.pathkeys == NIL ||
             ipath->indexselectivity < 1.0))
            *bitindexpaths = lappend(*bitindexpaths, ipath);
    }

    /*
     * If there were ScalarArrayOpExpr clauses that the index can't handle
     * natively, generate bitmap scan paths relying on executor-managed
     * ScalarArrayOpExpr.
     */
    if (skip_nonnative_saop)
    {
        indexpaths = build_index_paths(root, rel,
                                       index, clauses,
                                       false,
                                       ST_BITMAPSCAN,
                                       NULL,
                                       NULL);
        *bitindexpaths = list_concat(*bitindexpaths, indexpaths);
    }
}

get_join_index_paths()

static void get_join_index_paths ( PlannerInfo *  root, RelOptInfo *  rel, IndexOptInfo *  index, IndexClauseSet *  rclauseset, IndexClauseSet *  jclauseset, IndexClauseSet *  eclauseset, List **  bitindexpaths, Relids  relids, List **  considered_relids  )

static

Definition at line 608 of file indxpath.c.

References Assert, bms_equal_any(), bms_is_subset(), RestrictInfo::clause_relids, get_index_paths(), IndexClauseSet::indexclauses, lappend(), lfirst, list_concat(), MemSet, NIL, IndexOptInfo::nkeycolumns, IndexClauseSet::nonempty, and IndexClause::rinfo.

Referenced by consider_index_join_outer_rels().

{
    IndexClauseSet clauseset;
    int         indexcol;

    /* If we already considered this relids set, don't repeat the work */
    if (bms_equal_any(relids, *considered_relids))
        return;

    /* Identify indexclauses usable with this relids set */
    MemSet(&clauseset, 0, sizeof(clauseset));

    for (indexcol = 0; indexcol < index->nkeycolumns; indexcol++)
    {
        ListCell   *lc;

        /* First find applicable simple join clauses */
        foreach(lc, jclauseset->indexclauses[indexcol])
        {
            IndexClause *iclause = (IndexClause *) lfirst(lc);

            if (bms_is_subset(iclause->rinfo->clause_relids, relids))
                clauseset.indexclauses[indexcol] =
                    lappend(clauseset.indexclauses[indexcol], iclause);
        }

        /*
         * Add applicable eclass join clauses.  The clauses generated for each
         * column are redundant (cf generate_implied_equalities_for_column),
         * so we need at most one.  This is the only exception to the general
         * rule of using all available index clauses.
         */
        foreach(lc, eclauseset->indexclauses[indexcol])
        {
            IndexClause *iclause = (IndexClause *) lfirst(lc);

            if (bms_is_subset(iclause->rinfo->clause_relids, relids))
            {
                clauseset.indexclauses[indexcol] =
                    lappend(clauseset.indexclauses[indexcol], iclause);
                break;
            }
        }

        /* Add restriction clauses */
        clauseset.indexclauses[indexcol] =
            list_concat(clauseset.indexclauses[indexcol],
                        rclauseset->indexclauses[indexcol]);

        if (clauseset.indexclauses[indexcol] != NIL)
            clauseset.nonempty = true;
    }

    /* We should have found something, else caller passed silly relids */
    Assert(clauseset.nonempty);

    /* Build index path(s) using the collected set of clauses */
    get_index_paths(root, rel, index, &clauseset, bitindexpaths);

    /*
     * Remember we considered paths for this set of relids.
     */
    *considered_relids = lappend(*considered_relids, relids);
}

get_loop_count()

static double get_loop_count ( PlannerInfo *  root, Index  cur_relid, Relids  outer_relids  )

static

Definition at line 2000 of file indxpath.c.

References adjust_rowcount_for_semijoins(), Assert, bms_next_member(), IS_DUMMY_REL, RelOptInfo::relid, RelOptInfo::rows, PlannerInfo::simple_rel_array, and PlannerInfo::simple_rel_array_size.

Referenced by bitmap_and_cost_est(), bitmap_scan_cost_est(), build_index_paths(), and create_index_paths().

{
    double      result;
    int         outer_relid;

    /* For a non-parameterized path, just return 1.0 quickly */
    if (outer_relids == NULL)
        return 1.0;

    result = 0.0;
    outer_relid = -1;
    while ((outer_relid = bms_next_member(outer_relids, outer_relid)) >= 0)
    {
        RelOptInfo *outer_rel;
        double      rowcount;

        /* Paranoia: ignore bogus relid indexes */
        if (outer_relid >= root->simple_rel_array_size)
            continue;
        outer_rel = root->simple_rel_array[outer_relid];
        if (outer_rel == NULL)
            continue;
        Assert(outer_rel->relid == outer_relid);    /* sanity check on array */

        /* Other relation could be proven empty, if so ignore */
        if (IS_DUMMY_REL(outer_rel))
            continue;

        /* Otherwise, rel's rows estimate should be valid by now */
        Assert(outer_rel->rows > 0);

        /* Check to see if rel is on the inside of any semijoins */
        rowcount = adjust_rowcount_for_semijoins(root,
                                                 cur_relid,
                                                 outer_relid,
                                                 outer_rel->rows);

        /* Remember smallest row count estimate among the outer rels */
        if (result == 0.0 || result > rowcount)
            result = rowcount;
    }
    /* Return 1.0 if we found no valid relations (shouldn't happen) */
    return (result > 0.0) ? result : 1.0;
}

indexcol_is_bool_constant_for_query()

bool indexcol_is_bool_constant_for_query	(	IndexOptInfo *	index,
		int	indexcol
	)

Definition at line 3757 of file indxpath.c.

References RelOptInfo::baserestrictinfo, lfirst, match_boolean_index_clause(), IndexOptInfo::opfamily, RestrictInfo::pseudoconstant, and IndexOptInfo::rel.

Referenced by build_index_pathkeys().

{
    ListCell   *lc;

    /* If the index isn't boolean, we can't possibly get a match */
    if (!IsBooleanOpfamily(index->opfamily[indexcol]))
        return false;

    /* Check each restriction clause for the index's rel */
    foreach(lc, index->rel->baserestrictinfo)
    {
        RestrictInfo *rinfo = (RestrictInfo *) lfirst(lc);

        /*
         * As in match_clause_to_indexcol, never match pseudoconstants to
         * indexes.  (It might be semantically okay to do so here, but the
         * odds of getting a match are negligible, so don't waste the cycles.)
         */
        if (rinfo->pseudoconstant)
            continue;

        /* See if we can match the clause's expression to the index column */
        if (match_boolean_index_clause(rinfo, indexcol, index))
            return true;
    }

    return false;
}

is_pseudo_constant_for_index()

bool is_pseudo_constant_for_index	(	Node *	expr,
		IndexOptInfo *	index
	)

Definition at line 3891 of file indxpath.c.

References bms_is_member(), contain_volatile_functions(), pull_varnos(), IndexOptInfo::rel, and RelOptInfo::relid.

{
    /* pull_varnos is cheaper than volatility check, so do that first */
    if (bms_is_member(index->rel->relid, pull_varnos(expr)))
        return false;           /* no good, contains Var of table */
    if (contain_volatile_functions(expr))
        return false;           /* no good, volatile comparison value */
    return true;
}

match_boolean_index_clause()

static IndexClause * match_boolean_index_clause ( RestrictInfo *  rinfo, int  indexcol, IndexOptInfo *  index  )

static

Definition at line 2458 of file indxpath.c.

References arg, BooleanTest::arg, BooleanTest::booltesttype, RestrictInfo::clause, get_notclausearg(), IndexClause::indexcol, IndexClause::indexcols, IndexClause::indexquals, InvalidOid, IS_FALSE, is_notclause(), IS_TRUE, IsA, list_make1, IndexClause::lossy, make_opclause(), make_simple_restrictinfo, makeBoolConst(), makeNode, match_index_to_operand(), NIL, and IndexClause::rinfo.

Referenced by indexcol_is_bool_constant_for_query(), and match_clause_to_indexcol().

{
    Node       *clause = (Node *) rinfo->clause;
    Expr       *op = NULL;

    /* Direct match? */
    if (match_index_to_operand(clause, indexcol, index))
    {
        /* convert to indexkey = TRUE */
        op = make_opclause(BooleanEqualOperator, BOOLOID, false,
                           (Expr *) clause,
                           (Expr *) makeBoolConst(true, false),
                           InvalidOid, InvalidOid);
    }
    /* NOT clause? */
    else if (is_notclause(clause))
    {
        Node       *arg = (Node *) get_notclausearg((Expr *) clause);

        if (match_index_to_operand(arg, indexcol, index))
        {
            /* convert to indexkey = FALSE */
            op = make_opclause(BooleanEqualOperator, BOOLOID, false,
                               (Expr *) arg,
                               (Expr *) makeBoolConst(false, false),
                               InvalidOid, InvalidOid);
        }
    }

    /*
     * Since we only consider clauses at top level of WHERE, we can convert
     * indexkey IS TRUE and indexkey IS FALSE to index searches as well.  The
     * different meaning for NULL isn't important.
     */
    else if (clause && IsA(clause, BooleanTest))
    {
        BooleanTest *btest = (BooleanTest *) clause;
        Node       *arg = (Node *) btest->arg;

        if (btest->booltesttype == IS_TRUE &&
            match_index_to_operand(arg, indexcol, index))
        {
            /* convert to indexkey = TRUE */
            op = make_opclause(BooleanEqualOperator, BOOLOID, false,
                               (Expr *) arg,
                               (Expr *) makeBoolConst(true, false),
                               InvalidOid, InvalidOid);
        }
        else if (btest->booltesttype == IS_FALSE &&
                 match_index_to_operand(arg, indexcol, index))
        {
            /* convert to indexkey = FALSE */
            op = make_opclause(BooleanEqualOperator, BOOLOID, false,
                               (Expr *) arg,
                               (Expr *) makeBoolConst(false, false),
                               InvalidOid, InvalidOid);
        }
    }

    /*
     * If we successfully made an operator clause from the given qual, we must
     * wrap it in an IndexClause.  It's not lossy.
     */
    if (op)
    {
        IndexClause *iclause = makeNode(IndexClause);

        iclause->rinfo = rinfo;
        iclause->indexquals = list_make1(make_simple_restrictinfo(op));
        iclause->lossy = false;
        iclause->indexcol = indexcol;
        iclause->indexcols = NIL;
        return iclause;
    }

    return NULL;
}

match_clause_to_index()

static void match_clause_to_index ( PlannerInfo *  root, RestrictInfo *  rinfo, IndexOptInfo *  index, IndexClauseSet *  clauseset  )

static

Definition at line 2254 of file indxpath.c.

References IndexClauseSet::indexclauses, lappend(), lfirst, match_clause_to_indexcol(), IndexOptInfo::nkeycolumns, IndexClauseSet::nonempty, RestrictInfo::pseudoconstant, IndexOptInfo::rel, restriction_is_securely_promotable(), and IndexClause::rinfo.

Referenced by match_clauses_to_index(), and match_join_clauses_to_index().

{
    int         indexcol;

    /*
     * Never match pseudoconstants to indexes.  (Normally a match could not
     * happen anyway, since a pseudoconstant clause couldn't contain a Var,
     * but what if someone builds an expression index on a constant? It's not
     * totally unreasonable to do so with a partial index, either.)
     */
    if (rinfo->pseudoconstant)
        return;

    /*
     * If clause can't be used as an indexqual because it must wait till after
     * some lower-security-level restriction clause, reject it.
     */
    if (!restriction_is_securely_promotable(rinfo, index->rel))
        return;

    /* OK, check each index key column for a match */
    for (indexcol = 0; indexcol < index->nkeycolumns; indexcol++)
    {
        IndexClause *iclause;
        ListCell   *lc;

        /* Ignore duplicates */
        foreach(lc, clauseset->indexclauses[indexcol])
        {
            IndexClause *iclause = (IndexClause *) lfirst(lc);

            if (iclause->rinfo == rinfo)
                return;
        }

        /* OK, try to match the clause to the index column */
        iclause = match_clause_to_indexcol(root,
                                           rinfo,
                                           indexcol,
                                           index);
        if (iclause)
        {
            /* Success, so record it */
            clauseset->indexclauses[indexcol] =
                lappend(clauseset->indexclauses[indexcol], iclause);
            clauseset->nonempty = true;
            return;
        }
    }
}

match_clause_to_indexcol()

static IndexClause * match_clause_to_indexcol ( PlannerInfo *  root, RestrictInfo *  rinfo, int  indexcol, IndexOptInfo *  index  )

static

Definition at line 2373 of file indxpath.c.

References IndexOptInfo::amsearchnulls, NullTest::arg, NullTest::argisrow, Assert, RestrictInfo::clause, IndexClause::indexcol, IndexClause::indexcols, IndexClause::indexquals, IsA, list_make1, IndexClause::lossy, makeNode, match_boolean_index_clause(), match_funcclause_to_indexcol(), match_index_to_operand(), match_opclause_to_indexcol(), match_rowcompare_to_indexcol(), match_saopclause_to_indexcol(), NIL, IndexOptInfo::opfamily, and IndexClause::rinfo.

Referenced by match_clause_to_index().

{
    IndexClause *iclause;
    Expr       *clause = rinfo->clause;
    Oid         opfamily;

    Assert(indexcol < index->nkeycolumns);

    /*
     * Historically this code has coped with NULL clauses.  That's probably
     * not possible anymore, but we might as well continue to cope.
     */
    if (clause == NULL)
        return NULL;

    /* First check for boolean-index cases. */
    opfamily = index->opfamily[indexcol];
    if (IsBooleanOpfamily(opfamily))
    {
        iclause = match_boolean_index_clause(rinfo, indexcol, index);
        if (iclause)
            return iclause;
    }

    /*
     * Clause must be an opclause, funcclause, ScalarArrayOpExpr, or
     * RowCompareExpr.  Or, if the index supports it, we can handle IS
     * NULL/NOT NULL clauses.
     */
    if (IsA(clause, OpExpr))
    {
        return match_opclause_to_indexcol(root, rinfo, indexcol, index);
    }
    else if (IsA(clause, FuncExpr))
    {
        return match_funcclause_to_indexcol(root, rinfo, indexcol, index);
    }
    else if (IsA(clause, ScalarArrayOpExpr))
    {
        return match_saopclause_to_indexcol(rinfo, indexcol, index);
    }
    else if (IsA(clause, RowCompareExpr))
    {
        return match_rowcompare_to_indexcol(rinfo, indexcol, index);
    }
    else if (index->amsearchnulls && IsA(clause, NullTest))
    {
        NullTest   *nt = (NullTest *) clause;

        if (!nt->argisrow &&
            match_index_to_operand((Node *) nt->arg, indexcol, index))
        {
            iclause = makeNode(IndexClause);
            iclause->rinfo = rinfo;
            iclause->indexquals = list_make1(rinfo);
            iclause->lossy = false;
            iclause->indexcol = indexcol;
            iclause->indexcols = NIL;
            return iclause;
        }
    }

    return NULL;
}

match_clause_to_ordering_op()

static Expr * match_clause_to_ordering_op ( IndexOptInfo *  index, int  indexcol, Expr *  clause, Oid  pk_opfamily  )

static

Definition at line 3281 of file indxpath.c.

References OpExpr::args, Assert, contain_var_clause(), contain_volatile_functions(), get_commutator(), get_leftop(), get_op_opfamily_sortfamily(), get_rightop(), IndexOptInfo::indexcollations, IndexCollMatchesExprColl, InvalidOid, is_opclause(), list_make2, makeNode, match_index_to_operand(), IndexOptInfo::opfamily, OpExpr::opfuncid, and OpExpr::opno.

Referenced by match_pathkeys_to_index().

{
    Oid         opfamily;
    Oid         idxcollation;
    Node       *leftop,
               *rightop;
    Oid         expr_op;
    Oid         expr_coll;
    Oid         sortfamily;
    bool        commuted;

    Assert(indexcol < index->nkeycolumns);

    opfamily = index->opfamily[indexcol];
    idxcollation = index->indexcollations[indexcol];

    /*
     * Clause must be a binary opclause.
     */
    if (!is_opclause(clause))
        return NULL;
    leftop = get_leftop(clause);
    rightop = get_rightop(clause);
    if (!leftop || !rightop)
        return NULL;
    expr_op = ((OpExpr *) clause)->opno;
    expr_coll = ((OpExpr *) clause)->inputcollid;

    /*
     * We can forget the whole thing right away if wrong collation.
     */
    if (!IndexCollMatchesExprColl(idxcollation, expr_coll))
        return NULL;

    /*
     * Check for clauses of the form: (indexkey operator constant) or
     * (constant operator indexkey).
     */
    if (match_index_to_operand(leftop, indexcol, index) &&
        !contain_var_clause(rightop) &&
        !contain_volatile_functions(rightop))
    {
        commuted = false;
    }
    else if (match_index_to_operand(rightop, indexcol, index) &&
             !contain_var_clause(leftop) &&
             !contain_volatile_functions(leftop))
    {
        /* Might match, but we need a commuted operator */
        expr_op = get_commutator(expr_op);
        if (expr_op == InvalidOid)
            return NULL;
        commuted = true;
    }
    else
        return NULL;

    /*
     * Is the (commuted) operator an ordering operator for the opfamily? And
     * if so, does it yield the right sorting semantics?
     */
    sortfamily = get_op_opfamily_sortfamily(expr_op, opfamily);
    if (sortfamily != pk_opfamily)
        return NULL;

    /* We have a match.  Return clause or a commuted version thereof. */
    if (commuted)
    {
        OpExpr     *newclause = makeNode(OpExpr);

        /* flat-copy all the fields of clause */
        memcpy(newclause, clause, sizeof(OpExpr));

        /* commute it */
        newclause->opno = expr_op;
        newclause->opfuncid = InvalidOid;
        newclause->args = list_make2(rightop, leftop);

        clause = (Expr *) newclause;
    }

    return clause;
}

match_clauses_to_index()

static void match_clauses_to_index ( PlannerInfo *  root, List *  clauses, IndexOptInfo *  index, IndexClauseSet *  clauseset  )

static

Definition at line 2221 of file indxpath.c.

References lfirst_node, and match_clause_to_index().

Referenced by build_paths_for_OR(), match_eclass_clauses_to_index(), and match_restriction_clauses_to_index().

{
    ListCell   *lc;

    foreach(lc, clauses)
    {
        RestrictInfo *rinfo = lfirst_node(RestrictInfo, lc);

        match_clause_to_index(root, rinfo, index, clauseset);
    }
}

match_eclass_clauses_to_index()

static void match_eclass_clauses_to_index ( PlannerInfo *  root, IndexOptInfo *  index, IndexClauseSet *  clauseset  )

static

Definition at line 2183 of file indxpath.c.

References arg, ec_member_matches_indexcol(), generate_implied_equalities_for_column(), RelOptInfo::has_eclass_joins, ec_member_matches_arg::index, ec_member_matches_arg::indexcol, RelOptInfo::lateral_referencers, match_clauses_to_index(), IndexOptInfo::nkeycolumns, and IndexOptInfo::rel.

Referenced by create_index_paths().

{
    int         indexcol;

    /* No work if rel is not in any such ECs */
    if (!index->rel->has_eclass_joins)
        return;

    for (indexcol = 0; indexcol < index->nkeycolumns; indexcol++)
    {
        ec_member_matches_arg arg;
        List       *clauses;

        /* Generate clauses, skipping any that join to lateral_referencers */
        arg.index = index;
        arg.indexcol = indexcol;
        clauses = generate_implied_equalities_for_column(root,
                                                         index->rel,
                                                         ec_member_matches_indexcol,
                                                         (void *) &arg,
                                                         index->rel->lateral_referencers);

        /*
         * We have to check whether the results actually do match the index,
         * since for non-btree indexes the EC's equality operators might not
         * be in the index opclass (cf ec_member_matches_indexcol).
         */
        match_clauses_to_index(root, clauses, index, clauseset);
    }
}

match_funcclause_to_indexcol()

static IndexClause * match_funcclause_to_indexcol ( PlannerInfo *  root, RestrictInfo *  rinfo, int  indexcol, IndexOptInfo *  index  )

static

Definition at line 2663 of file indxpath.c.

References FuncExpr::args, RestrictInfo::clause, FuncExpr::funcid, get_index_clause_from_support(), lfirst, and match_index_to_operand().

Referenced by match_clause_to_indexcol().

{
    FuncExpr   *clause = (FuncExpr *) rinfo->clause;
    int         indexarg;
    ListCell   *lc;

    /*
     * We have no built-in intelligence about function clauses, but if there's
     * a planner support function, it might be able to do something.  But, to
     * cut down on wasted planning cycles, only call the support function if
     * at least one argument matches the target index column.
     *
     * Note that we don't insist on the other arguments being pseudoconstants;
     * the support function has to check that.  This is to allow cases where
     * only some of the other arguments need to be included in the indexqual.
     */
    indexarg = 0;
    foreach(lc, clause->args)
    {
        Node       *op = (Node *) lfirst(lc);

        if (match_index_to_operand(op, indexcol, index))
        {
            return get_index_clause_from_support(root,
                                                 rinfo,
                                                 clause->funcid,
                                                 indexarg,
                                                 indexcol,
                                                 index);
        }

        indexarg++;
    }

    return NULL;
}

match_index_to_operand()

bool match_index_to_operand	(	Node *	operand,
		int	indexcol,
		IndexOptInfo *	index
	)

Definition at line 3806 of file indxpath.c.

References arg, elog, equal(), ERROR, i, IndexOptInfo::indexkeys, IndexOptInfo::indexprs, IsA, lfirst, list_head(), lnext(), IndexOptInfo::rel, and RelOptInfo::relid.

Referenced by ec_member_matches_indexcol(), expand_indexqual_rowcompare(), get_actual_variable_range(), match_boolean_index_clause(), match_clause_to_indexcol(), match_clause_to_ordering_op(), match_funcclause_to_indexcol(), match_opclause_to_indexcol(), match_rowcompare_to_indexcol(), match_saopclause_to_indexcol(), and relation_has_unique_index_for().

{
    int         indkey;

    /*
     * Ignore any RelabelType node above the operand.   This is needed to be
     * able to apply indexscanning in binary-compatible-operator cases. Note:
     * we can assume there is at most one RelabelType node;
     * eval_const_expressions() will have simplified if more than one.
     */
    if (operand && IsA(operand, RelabelType))
        operand = (Node *) ((RelabelType *) operand)->arg;

    indkey = index->indexkeys[indexcol];
    if (indkey != 0)
    {
        /*
         * Simple index column; operand must be a matching Var.
         */
        if (operand && IsA(operand, Var) &&
            index->rel->relid == ((Var *) operand)->varno &&
            indkey == ((Var *) operand)->varattno)
            return true;
    }
    else
    {
        /*
         * Index expression; find the correct expression.  (This search could
         * be avoided, at the cost of complicating all the callers of this
         * routine; doesn't seem worth it.)
         */
        ListCell   *indexpr_item;
        int         i;
        Node       *indexkey;

        indexpr_item = list_head(index->indexprs);
        for (i = 0; i < indexcol; i++)
        {
            if (index->indexkeys[i] == 0)
            {
                if (indexpr_item == NULL)
                    elog(ERROR, "wrong number of index expressions");
                indexpr_item = lnext(index->indexprs, indexpr_item);
            }
        }
        if (indexpr_item == NULL)
            elog(ERROR, "wrong number of index expressions");
        indexkey = (Node *) lfirst(indexpr_item);

        /*
         * Does it match the operand?  Again, strip any relabeling.
         */
        if (indexkey && IsA(indexkey, RelabelType))
            indexkey = (Node *) ((RelabelType *) indexkey)->arg;

        if (equal(indexkey, operand))
            return true;
    }

    return false;
}

match_join_clauses_to_index()

static void match_join_clauses_to_index ( PlannerInfo *  root, RelOptInfo *  rel, IndexOptInfo *  index, IndexClauseSet *  clauseset, List **  joinorclauses  )

static

Definition at line 2153 of file indxpath.c.

References join_clause_is_movable_to(), RelOptInfo::joininfo, lappend(), lfirst, match_clause_to_index(), and restriction_is_or_clause().

Referenced by create_index_paths().

{
    ListCell   *lc;

    /* Scan the rel's join clauses */
    foreach(lc, rel->joininfo)
    {
        RestrictInfo *rinfo = (RestrictInfo *) lfirst(lc);

        /* Check if clause can be moved to this rel */
        if (!join_clause_is_movable_to(rinfo, rel))
            continue;

        /* Potentially usable, so see if it matches the index or is an OR */
        if (restriction_is_or_clause(rinfo))
            *joinorclauses = lappend(*joinorclauses, rinfo);
        else
            match_clause_to_index(root, rinfo, index, clauseset);
    }
}

match_opclause_to_indexcol()

static IndexClause * match_opclause_to_indexcol ( PlannerInfo *  root, RestrictInfo *  rinfo, int  indexcol, IndexOptInfo *  index  )

static

Definition at line 2544 of file indxpath.c.

References OpExpr::args, bms_is_member(), RestrictInfo::clause, commute_restrictinfo(), contain_volatile_functions(), get_commutator(), get_index_clause_from_support(), IndexClause::indexcol, IndexOptInfo::indexcollations, IndexCollMatchesExprColl, IndexClause::indexcols, IndexClause::indexquals, OpExpr::inputcollid, RestrictInfo::left_relids, linitial, list_length(), list_make1, IndexClause::lossy, lsecond, makeNode, match_index_to_operand(), NIL, OidIsValid, op_in_opfamily(), IndexOptInfo::opfamily, OpExpr::opfuncid, OpExpr::opno, IndexOptInfo::rel, RelOptInfo::relid, RestrictInfo::right_relids, IndexClause::rinfo, and set_opfuncid().

Referenced by match_clause_to_indexcol().

{
    IndexClause *iclause;
    OpExpr     *clause = (OpExpr *) rinfo->clause;
    Node       *leftop,
               *rightop;
    Oid         expr_op;
    Oid         expr_coll;
    Index       index_relid;
    Oid         opfamily;
    Oid         idxcollation;

    /*
     * Only binary operators need apply.  (In theory, a planner support
     * function could do something with a unary operator, but it seems
     * unlikely to be worth the cycles to check.)
     */
    if (list_length(clause->args) != 2)
        return NULL;

    leftop = (Node *) linitial(clause->args);
    rightop = (Node *) lsecond(clause->args);
    expr_op = clause->opno;
    expr_coll = clause->inputcollid;

    index_relid = index->rel->relid;
    opfamily = index->opfamily[indexcol];
    idxcollation = index->indexcollations[indexcol];

    /*
     * Check for clauses of the form: (indexkey operator constant) or
     * (constant operator indexkey).  See match_clause_to_indexcol's notes
     * about const-ness.
     *
     * Note that we don't ask the support function about clauses that don't
     * have one of these forms.  Again, in principle it might be possible to
     * do something, but it seems unlikely to be worth the cycles to check.
     */
    if (match_index_to_operand(leftop, indexcol, index) &&
        !bms_is_member(index_relid, rinfo->right_relids) &&
        !contain_volatile_functions(rightop))
    {
        if (IndexCollMatchesExprColl(idxcollation, expr_coll) &&
            op_in_opfamily(expr_op, opfamily))
        {
            iclause = makeNode(IndexClause);
            iclause->rinfo = rinfo;
            iclause->indexquals = list_make1(rinfo);
            iclause->lossy = false;
            iclause->indexcol = indexcol;
            iclause->indexcols = NIL;
            return iclause;
        }

        /*
         * If we didn't find a member of the index's opfamily, try the support
         * function for the operator's underlying function.
         */
        set_opfuncid(clause);   /* make sure we have opfuncid */
        return get_index_clause_from_support(root,
                                             rinfo,
                                             clause->opfuncid,
                                             0, /* indexarg on left */
                                             indexcol,
                                             index);
    }

    if (match_index_to_operand(rightop, indexcol, index) &&
        !bms_is_member(index_relid, rinfo->left_relids) &&
        !contain_volatile_functions(leftop))
    {
        if (IndexCollMatchesExprColl(idxcollation, expr_coll))
        {
            Oid         comm_op = get_commutator(expr_op);

            if (OidIsValid(comm_op) &&
                op_in_opfamily(comm_op, opfamily))
            {
                RestrictInfo *commrinfo;

                /* Build a commuted OpExpr and RestrictInfo */
                commrinfo = commute_restrictinfo(rinfo, comm_op);

                /* Make an IndexClause showing that as a derived qual */
                iclause = makeNode(IndexClause);
                iclause->rinfo = rinfo;
                iclause->indexquals = list_make1(commrinfo);
                iclause->lossy = false;
                iclause->indexcol = indexcol;
                iclause->indexcols = NIL;
                return iclause;
            }
        }

        /*
         * If we didn't find a member of the index's opfamily, try the support
         * function for the operator's underlying function.
         */
        set_opfuncid(clause);   /* make sure we have opfuncid */
        return get_index_clause_from_support(root,
                                             rinfo,
                                             clause->opfuncid,
                                             1, /* indexarg on right */
                                             indexcol,
                                             index);
    }

    return NULL;
}

match_pathkeys_to_index()

static void match_pathkeys_to_index ( IndexOptInfo *  index, List *  pathkeys, List **  orderby_clauses_p, List **  clause_columns_p  )

static

Definition at line 3166 of file indxpath.c.

References IndexOptInfo::amcanorderbyop, bms_equal(), BTLessStrategyNumber, EquivalenceClass::ec_has_volatile, EquivalenceClass::ec_members, EquivalenceMember::em_expr, EquivalenceMember::em_relids, lappend(), lappend_int(), lfirst, match_clause_to_ordering_op(), member, NIL, IndexOptInfo::nkeycolumns, PathKey::pk_eclass, PathKey::pk_nulls_first, PathKey::pk_opfamily, PathKey::pk_strategy, IndexOptInfo::rel, and RelOptInfo::relids.

Referenced by build_index_paths().

{
    List       *orderby_clauses = NIL;
    List       *clause_columns = NIL;
    ListCell   *lc1;

    *orderby_clauses_p = NIL;   /* set default results */
    *clause_columns_p = NIL;

    /* Only indexes with the amcanorderbyop property are interesting here */
    if (!index->amcanorderbyop)
        return;

    foreach(lc1, pathkeys)
    {
        PathKey    *pathkey = (PathKey *) lfirst(lc1);
        bool        found = false;
        ListCell   *lc2;

        /*
         * Note: for any failure to match, we just return NIL immediately.
         * There is no value in matching just some of the pathkeys.
         */

        /* Pathkey must request default sort order for the target opfamily */
        if (pathkey->pk_strategy != BTLessStrategyNumber ||
            pathkey->pk_nulls_first)
            return;

        /* If eclass is volatile, no hope of using an indexscan */
        if (pathkey->pk_eclass->ec_has_volatile)
            return;

        /*
         * Try to match eclass member expression(s) to index.  Note that child
         * EC members are considered, but only when they belong to the target
         * relation.  (Unlike regular members, the same expression could be a
         * child member of more than one EC.  Therefore, the same index could
         * be considered to match more than one pathkey list, which is OK
         * here.  See also get_eclass_for_sort_expr.)
         */
        foreach(lc2, pathkey->pk_eclass->ec_members)
        {
            EquivalenceMember *member = (EquivalenceMember *) lfirst(lc2);
            int         indexcol;

            /* No possibility of match if it references other relations */
            if (!bms_equal(member->em_relids, index->rel->relids))
                continue;

            /*
             * We allow any column of the index to match each pathkey; they
             * don't have to match left-to-right as you might expect.  This is
             * correct for GiST, and it doesn't matter for SP-GiST because
             * that doesn't handle multiple columns anyway, and no other
             * existing AMs support amcanorderbyop.  We might need different
             * logic in future for other implementations.
             */
            for (indexcol = 0; indexcol < index->nkeycolumns; indexcol++)
            {
                Expr       *expr;

                expr = match_clause_to_ordering_op(index,
                                                   indexcol,
                                                   member->em_expr,
                                                   pathkey->pk_opfamily);
                if (expr)
                {
                    orderby_clauses = lappend(orderby_clauses, expr);
                    clause_columns = lappend_int(clause_columns, indexcol);
                    found = true;
                    break;
                }
            }

            if (found)          /* don't want to look at remaining members */
                break;
        }

        if (!found)             /* fail if no match for this pathkey */
            return;
    }

    *orderby_clauses_p = orderby_clauses;   /* success! */
    *clause_columns_p = clause_columns;
}

match_restriction_clauses_to_index()

static void match_restriction_clauses_to_index ( PlannerInfo *  root, IndexOptInfo *  index, IndexClauseSet *  clauseset  )

static

Definition at line 2138 of file indxpath.c.

References IndexOptInfo::indrestrictinfo, and match_clauses_to_index().

Referenced by create_index_paths().

{
    /* We can ignore clauses that are implied by the index predicate */
    match_clauses_to_index(root, index->indrestrictinfo, index, clauseset);
}

match_rowcompare_to_indexcol()

static IndexClause * match_rowcompare_to_indexcol ( RestrictInfo *  rinfo, int  indexcol, IndexOptInfo *  index  )

static

Definition at line 2841 of file indxpath.c.

References bms_is_member(), BTGreaterEqualStrategyNumber, BTGreaterStrategyNumber, BTLessEqualStrategyNumber, BTLessStrategyNumber, RestrictInfo::clause, contain_volatile_functions(), expand_indexqual_rowcompare(), get_commutator(), get_op_opfamily_strategy(), IndexOptInfo::indexcollations, IndexCollMatchesExprColl, RowCompareExpr::inputcollids, InvalidOid, RowCompareExpr::largs, linitial, linitial_oid, match_index_to_operand(), IndexOptInfo::opfamily, RowCompareExpr::opnos, pull_varnos(), RowCompareExpr::rargs, IndexOptInfo::rel, IndexOptInfo::relam, and RelOptInfo::relid.

Referenced by match_clause_to_indexcol().

{
    RowCompareExpr *clause = (RowCompareExpr *) rinfo->clause;
    Index       index_relid;
    Oid         opfamily;
    Oid         idxcollation;
    Node       *leftop,
               *rightop;
    bool        var_on_left;
    Oid         expr_op;
    Oid         expr_coll;

    /* Forget it if we're not dealing with a btree index */
    if (index->relam != BTREE_AM_OID)
        return NULL;

    index_relid = index->rel->relid;
    opfamily = index->opfamily[indexcol];
    idxcollation = index->indexcollations[indexcol];

    /*
     * We could do the matching on the basis of insisting that the opfamily
     * shown in the RowCompareExpr be the same as the index column's opfamily,
     * but that could fail in the presence of reverse-sort opfamilies: it'd be
     * a matter of chance whether RowCompareExpr had picked the forward or
     * reverse-sort family.  So look only at the operator, and match if it is
     * a member of the index's opfamily (after commutation, if the indexkey is
     * on the right).  We'll worry later about whether any additional
     * operators are matchable to the index.
     */
    leftop = (Node *) linitial(clause->largs);
    rightop = (Node *) linitial(clause->rargs);
    expr_op = linitial_oid(clause->opnos);
    expr_coll = linitial_oid(clause->inputcollids);

    /* Collations must match, if relevant */
    if (!IndexCollMatchesExprColl(idxcollation, expr_coll))
        return NULL;

    /*
     * These syntactic tests are the same as in match_opclause_to_indexcol()
     */
    if (match_index_to_operand(leftop, indexcol, index) &&
        !bms_is_member(index_relid, pull_varnos(rightop)) &&
        !contain_volatile_functions(rightop))
    {
        /* OK, indexkey is on left */
        var_on_left = true;
    }
    else if (match_index_to_operand(rightop, indexcol, index) &&
             !bms_is_member(index_relid, pull_varnos(leftop)) &&
             !contain_volatile_functions(leftop))
    {
        /* indexkey is on right, so commute the operator */
        expr_op = get_commutator(expr_op);
        if (expr_op == InvalidOid)
            return NULL;
        var_on_left = false;
    }
    else
        return NULL;

    /* We're good if the operator is the right type of opfamily member */
    switch (get_op_opfamily_strategy(expr_op, opfamily))
    {
        case BTLessStrategyNumber:
        case BTLessEqualStrategyNumber:
        case BTGreaterEqualStrategyNumber:
        case BTGreaterStrategyNumber:
            return expand_indexqual_rowcompare(rinfo,
                                               indexcol,
                                               index,
                                               expr_op,
                                               var_on_left);
    }

    return NULL;
}

match_saopclause_to_indexcol()

static IndexClause * match_saopclause_to_indexcol ( RestrictInfo *  rinfo, int  indexcol, IndexOptInfo *  index  )

static

Definition at line 2774 of file indxpath.c.

References ScalarArrayOpExpr::args, bms_is_member(), RestrictInfo::clause, contain_volatile_functions(), IndexClause::indexcol, IndexOptInfo::indexcollations, IndexCollMatchesExprColl, IndexClause::indexcols, IndexClause::indexquals, ScalarArrayOpExpr::inputcollid, linitial, list_make1, IndexClause::lossy, lsecond, makeNode, match_index_to_operand(), NIL, op_in_opfamily(), IndexOptInfo::opfamily, ScalarArrayOpExpr::opno, pull_varnos(), IndexOptInfo::rel, RelOptInfo::relid, IndexClause::rinfo, and ScalarArrayOpExpr::useOr.

Referenced by match_clause_to_indexcol().

{
    ScalarArrayOpExpr *saop = (ScalarArrayOpExpr *) rinfo->clause;
    Node       *leftop,
               *rightop;
    Relids      right_relids;
    Oid         expr_op;
    Oid         expr_coll;
    Index       index_relid;
    Oid         opfamily;
    Oid         idxcollation;

    /* We only accept ANY clauses, not ALL */
    if (!saop->useOr)
        return NULL;
    leftop = (Node *) linitial(saop->args);
    rightop = (Node *) lsecond(saop->args);
    right_relids = pull_varnos(rightop);
    expr_op = saop->opno;
    expr_coll = saop->inputcollid;

    index_relid = index->rel->relid;
    opfamily = index->opfamily[indexcol];
    idxcollation = index->indexcollations[indexcol];

    /*
     * We must have indexkey on the left and a pseudo-constant array argument.
     */
    if (match_index_to_operand(leftop, indexcol, index) &&
        !bms_is_member(index_relid, right_relids) &&
        !contain_volatile_functions(rightop))
    {
        if (IndexCollMatchesExprColl(idxcollation, expr_coll) &&
            op_in_opfamily(expr_op, opfamily))
        {
            IndexClause *iclause = makeNode(IndexClause);

            iclause->rinfo = rinfo;
            iclause->indexquals = list_make1(rinfo);
            iclause->lossy = false;
            iclause->indexcol = indexcol;
            iclause->indexcols = NIL;
            return iclause;
        }

        /*
         * We do not currently ask support functions about ScalarArrayOpExprs,
         * though in principle we could.
         */
    }

    return NULL;
}

path_usage_comparator()

static int path_usage_comparator ( const void *  a, const void *  b  )

static

Definition at line 1574 of file indxpath.c.

References cost_bitmap_tree_node(), and PathClauseUsage::path.

Referenced by choose_bitmap_and().

{
    PathClauseUsage *pa = *(PathClauseUsage *const *) a;
    PathClauseUsage *pb = *(PathClauseUsage *const *) b;
    Cost        acost;
    Cost        bcost;
    Selectivity aselec;
    Selectivity bselec;

    cost_bitmap_tree_node(pa->path, &acost, &aselec);
    cost_bitmap_tree_node(pb->path, &bcost, &bselec);

    /*
     * If costs are the same, sort by selectivity.
     */
    if (acost < bcost)
        return -1;
    if (acost > bcost)
        return 1;

    if (aselec < bselec)
        return -1;
    if (aselec > bselec)
        return 1;

    return 0;
}

relation_has_unique_index_for()

bool relation_has_unique_index_for	(	PlannerInfo *	root,
		RelOptInfo *	rel,
		List *	restrictlist,
		List *	exprlist,
		List *	oprlist
	)

Definition at line 3586 of file indxpath.c.

References Assert, RelOptInfo::baserestrictinfo, bms_is_empty(), RestrictInfo::clause, forboth, get_leftop(), get_rightop(), IndexOptInfo::immediate, RelOptInfo::indexlist, IndexOptInfo::indpred, lappend(), RestrictInfo::left_relids, lfirst, lfirst_oid, list_length(), list_member_oid(), match_index_to_operand(), RestrictInfo::mergeopfamilies, NIL, IndexOptInfo::nkeycolumns, op_in_opfamily(), IndexOptInfo::opfamily, RestrictInfo::outer_is_left, IndexOptInfo::predOK, RestrictInfo::right_relids, and IndexOptInfo::unique.

Referenced by create_unique_path(), and rel_is_distinct_for().

{
    ListCell   *ic;

    Assert(list_length(exprlist) == list_length(oprlist));

    /* Short-circuit if no indexes... */
    if (rel->indexlist == NIL)
        return false;

    /*
     * Examine the rel's restriction clauses for usable var = const clauses
     * that we can add to the restrictlist.
     */
    foreach(ic, rel->baserestrictinfo)
    {
        RestrictInfo *restrictinfo = (RestrictInfo *) lfirst(ic);

        /*
         * Note: can_join won't be set for a restriction clause, but
         * mergeopfamilies will be if it has a mergejoinable operator and
         * doesn't contain volatile functions.
         */
        if (restrictinfo->mergeopfamilies == NIL)
            continue;           /* not mergejoinable */

        /*
         * The clause certainly doesn't refer to anything but the given rel.
         * If either side is pseudoconstant then we can use it.
         */
        if (bms_is_empty(restrictinfo->left_relids))
        {
            /* righthand side is inner */
            restrictinfo->outer_is_left = true;
        }
        else if (bms_is_empty(restrictinfo->right_relids))
        {
            /* lefthand side is inner */
            restrictinfo->outer_is_left = false;
        }
        else
            continue;

        /* OK, add to list */
        restrictlist = lappend(restrictlist, restrictinfo);
    }

    /* Short-circuit the easy case */
    if (restrictlist == NIL && exprlist == NIL)
        return false;

    /* Examine each index of the relation ... */
    foreach(ic, rel->indexlist)
    {
        IndexOptInfo *ind = (IndexOptInfo *) lfirst(ic);
        int         c;

        /*
         * If the index is not unique, or not immediately enforced, or if it's
         * a partial index that doesn't match the query, it's useless here.
         */
        if (!ind->unique || !ind->immediate ||
            (ind->indpred != NIL && !ind->predOK))
            continue;

        /*
         * Try to find each index column in the lists of conditions.  This is
         * O(N^2) or worse, but we expect all the lists to be short.
         */
        for (c = 0; c < ind->nkeycolumns; c++)
        {
            bool        matched = false;
            ListCell   *lc;
            ListCell   *lc2;

            foreach(lc, restrictlist)
            {
                RestrictInfo *rinfo = (RestrictInfo *) lfirst(lc);
                Node       *rexpr;

                /*
                 * The condition's equality operator must be a member of the
                 * index opfamily, else it is not asserting the right kind of
                 * equality behavior for this index.  We check this first
                 * since it's probably cheaper than match_index_to_operand().
                 */
                if (!list_member_oid(rinfo->mergeopfamilies, ind->opfamily[c]))
                    continue;

                /*
                 * XXX at some point we may need to check collations here too.
                 * For the moment we assume all collations reduce to the same
                 * notion of equality.
                 */

                /* OK, see if the condition operand matches the index key */
                if (rinfo->outer_is_left)
                    rexpr = get_rightop(rinfo->clause);
                else
                    rexpr = get_leftop(rinfo->clause);

                if (match_index_to_operand(rexpr, c, ind))
                {
                    matched = true; /* column is unique */
                    break;
                }
            }

            if (matched)
                continue;

            forboth(lc, exprlist, lc2, oprlist)
            {
                Node       *expr = (Node *) lfirst(lc);
                Oid         opr = lfirst_oid(lc2);

                /* See if the expression matches the index key */
                if (!match_index_to_operand(expr, c, ind))
                    continue;

                /*
                 * The equality operator must be a member of the index
                 * opfamily, else it is not asserting the right kind of
                 * equality behavior for this index.  We assume the caller
                 * determined it is an equality operator, so we don't need to
                 * check any more tightly than this.
                 */
                if (!op_in_opfamily(opr, ind->opfamily[c]))
                    continue;

                /*
                 * XXX at some point we may need to check collations here too.
                 * For the moment we assume all collations reduce to the same
                 * notion of equality.
                 */

                matched = true; /* column is unique */
                break;
            }

            if (!matched)
                break;          /* no match; this index doesn't help us */
        }

        /* Matched all key columns of this index? */
        if (c == ind->nkeycolumns)
            return true;
    }

    return false;
}