paths.h

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/*-------------------------------------------------------------------------
 *
 * paths.h
 *    prototypes for various files in optimizer/path
 *
 *
 * Portions Copyright (c) 1996-2013, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 * src/include/optimizer/paths.h
 *
 *-------------------------------------------------------------------------
 */
#ifndef PATHS_H
#define PATHS_H

#include "nodes/relation.h"


/*
 * allpaths.c
 */
extern bool enable_geqo;
extern int  geqo_threshold;

/* Hook for plugins to replace standard_join_search() */
typedef RelOptInfo *(*join_search_hook_type) (PlannerInfo *root,
                                                          int levels_needed,
                                                          List *initial_rels);
extern PGDLLIMPORT join_search_hook_type join_search_hook;


extern RelOptInfo *make_one_rel(PlannerInfo *root, List *joinlist);
extern RelOptInfo *standard_join_search(PlannerInfo *root, int levels_needed,
                     List *initial_rels);

#ifdef OPTIMIZER_DEBUG
extern void debug_print_rel(PlannerInfo *root, RelOptInfo *rel);
#endif

/*
 * indxpath.c
 *    routines to generate index paths
 */
extern void create_index_paths(PlannerInfo *root, RelOptInfo *rel);
extern List *generate_bitmap_or_paths(PlannerInfo *root, RelOptInfo *rel,
                         List *clauses, List *other_clauses,
                         bool restriction_only);
extern bool relation_has_unique_index_for(PlannerInfo *root, RelOptInfo *rel,
                              List *restrictlist,
                              List *exprlist, List *oprlist);
extern bool match_index_to_operand(Node *operand, int indexcol,
                       IndexOptInfo *index);
extern void expand_indexqual_conditions(IndexOptInfo *index,
                            List *indexclauses, List *indexclausecols,
                            List **indexquals_p, List **indexqualcols_p);
extern void check_partial_indexes(PlannerInfo *root, RelOptInfo *rel);
extern Expr *adjust_rowcompare_for_index(RowCompareExpr *clause,
                            IndexOptInfo *index,
                            int indexcol,
                            List **indexcolnos,
                            bool *var_on_left_p);

/*
 * orindxpath.c
 *    additional routines for indexable OR clauses
 */
extern bool create_or_index_quals(PlannerInfo *root, RelOptInfo *rel);

/*
 * tidpath.h
 *    routines to generate tid paths
 */
extern void create_tidscan_paths(PlannerInfo *root, RelOptInfo *rel);

/*
 * joinpath.c
 *     routines to create join paths
 */
extern void add_paths_to_joinrel(PlannerInfo *root, RelOptInfo *joinrel,
                     RelOptInfo *outerrel, RelOptInfo *innerrel,
                     JoinType jointype, SpecialJoinInfo *sjinfo,
                     List *restrictlist);

/*
 * joinrels.c
 *    routines to determine which relations to join
 */
extern void join_search_one_level(PlannerInfo *root, int level);
extern RelOptInfo *make_join_rel(PlannerInfo *root,
              RelOptInfo *rel1, RelOptInfo *rel2);
extern bool have_join_order_restriction(PlannerInfo *root,
                            RelOptInfo *rel1, RelOptInfo *rel2);

/*
 * equivclass.c
 *    routines for managing EquivalenceClasses
 */
typedef bool (*ec_matches_callback_type) (PlannerInfo *root,
                                                      RelOptInfo *rel,
                                                      EquivalenceClass *ec,
                                                      EquivalenceMember *em,
                                                      void *arg);

extern bool process_equivalence(PlannerInfo *root, RestrictInfo *restrictinfo,
                    bool below_outer_join);
extern Expr *canonicalize_ec_expression(Expr *expr,
                           Oid req_type, Oid req_collation);
extern void reconsider_outer_join_clauses(PlannerInfo *root);
extern EquivalenceClass *get_eclass_for_sort_expr(PlannerInfo *root,
                         Expr *expr,
                         List *opfamilies,
                         Oid opcintype,
                         Oid collation,
                         Index sortref,
                         Relids rel,
                         bool create_it);
extern void generate_base_implied_equalities(PlannerInfo *root);
extern List *generate_join_implied_equalities(PlannerInfo *root,
                                 Relids join_relids,
                                 Relids outer_relids,
                                 RelOptInfo *inner_rel);
extern bool exprs_known_equal(PlannerInfo *root, Node *item1, Node *item2);
extern void add_child_rel_equivalences(PlannerInfo *root,
                           AppendRelInfo *appinfo,
                           RelOptInfo *parent_rel,
                           RelOptInfo *child_rel);
extern void mutate_eclass_expressions(PlannerInfo *root,
                          Node *(*mutator) (),
                          void *context,
                          bool include_child_exprs);
extern List *generate_implied_equalities_for_column(PlannerInfo *root,
                                       RelOptInfo *rel,
                                       ec_matches_callback_type callback,
                                       void *callback_arg,
                                       Relids prohibited_rels);
extern bool have_relevant_eclass_joinclause(PlannerInfo *root,
                                RelOptInfo *rel1, RelOptInfo *rel2);
extern bool has_relevant_eclass_joinclause(PlannerInfo *root,
                               RelOptInfo *rel1);
extern bool eclass_useful_for_merging(EquivalenceClass *eclass,
                          RelOptInfo *rel);
extern bool is_redundant_derived_clause(RestrictInfo *rinfo, List *clauselist);

/*
 * pathkeys.c
 *    utilities for matching and building path keys
 */
typedef enum
{
    PATHKEYS_EQUAL,             /* pathkeys are identical */
    PATHKEYS_BETTER1,           /* pathkey 1 is a superset of pathkey 2 */
    PATHKEYS_BETTER2,           /* vice versa */
    PATHKEYS_DIFFERENT          /* neither pathkey includes the other */
} PathKeysComparison;

extern PathKeysComparison compare_pathkeys(List *keys1, List *keys2);
extern bool pathkeys_contained_in(List *keys1, List *keys2);
extern Path *get_cheapest_path_for_pathkeys(List *paths, List *pathkeys,
                               Relids required_outer,
                               CostSelector cost_criterion);
extern Path *get_cheapest_fractional_path_for_pathkeys(List *paths,
                                          List *pathkeys,
                                          Relids required_outer,
                                          double fraction);
extern List *build_index_pathkeys(PlannerInfo *root, IndexOptInfo *index,
                     ScanDirection scandir);
extern List *convert_subquery_pathkeys(PlannerInfo *root, RelOptInfo *rel,
                          List *subquery_pathkeys);
extern List *build_join_pathkeys(PlannerInfo *root,
                    RelOptInfo *joinrel,
                    JoinType jointype,
                    List *outer_pathkeys);
extern List *make_pathkeys_for_sortclauses(PlannerInfo *root,
                              List *sortclauses,
                              List *tlist);
extern void initialize_mergeclause_eclasses(PlannerInfo *root,
                                RestrictInfo *restrictinfo);
extern void update_mergeclause_eclasses(PlannerInfo *root,
                            RestrictInfo *restrictinfo);
extern List *find_mergeclauses_for_pathkeys(PlannerInfo *root,
                               List *pathkeys,
                               bool outer_keys,
                               List *restrictinfos);
extern List *select_outer_pathkeys_for_merge(PlannerInfo *root,
                                List *mergeclauses,
                                RelOptInfo *joinrel);
extern List *make_inner_pathkeys_for_merge(PlannerInfo *root,
                              List *mergeclauses,
                              List *outer_pathkeys);
extern List *truncate_useless_pathkeys(PlannerInfo *root,
                          RelOptInfo *rel,
                          List *pathkeys);
extern bool has_useful_pathkeys(PlannerInfo *root, RelOptInfo *rel);

#endif   /* PATHS_H */