paths.h

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/*-------------------------------------------------------------------------
 *
 * paths.h
 *    prototypes for various files in optimizer/path
 *
 *
 * Portions Copyright (c) 1996-2025, 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/pathnodes.h"
 
 
/*
 * allpaths.c
 */
extern PGDLLIMPORT bool enable_geqo;
extern PGDLLIMPORT int geqo_threshold;
extern PGDLLIMPORT int min_parallel_table_scan_size;
extern PGDLLIMPORT int min_parallel_index_scan_size;
extern PGDLLIMPORT bool enable_group_by_reordering;
 
/* Hook for plugins to get control in set_rel_pathlist() */
typedef void (*set_rel_pathlist_hook_type) (PlannerInfo *root,
                                            RelOptInfo *rel,
                                            Index rti,
                                            RangeTblEntry *rte);
extern PGDLLIMPORT set_rel_pathlist_hook_type set_rel_pathlist_hook;
 
/* Hook for plugins to get control in add_paths_to_joinrel() */
typedef void (*set_join_pathlist_hook_type) (PlannerInfo *root,
                                             RelOptInfo *joinrel,
                                             RelOptInfo *outerrel,
                                             RelOptInfo *innerrel,
                                             JoinType jointype,
                                             JoinPathExtraData *extra);
extern PGDLLIMPORT set_join_pathlist_hook_type set_join_pathlist_hook;
 
/* 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);
 
extern void generate_gather_paths(PlannerInfo *root, RelOptInfo *rel,
                                  bool override_rows);
extern void generate_useful_gather_paths(PlannerInfo *root, RelOptInfo *rel,
                                         bool override_rows);
extern int  compute_parallel_worker(RelOptInfo *rel, double heap_pages,
                                    double index_pages, int max_workers);
extern void create_partial_bitmap_paths(PlannerInfo *root, RelOptInfo *rel,
                                        Path *bitmapqual);
extern void generate_partitionwise_join_paths(PlannerInfo *root,
                                              RelOptInfo *rel);
 
/*
 * indxpath.c
 *    routines to generate index paths
 */
extern void create_index_paths(PlannerInfo *root, RelOptInfo *rel);
extern bool relation_has_unique_index_for(PlannerInfo *root, RelOptInfo *rel,
                                          List *restrictlist,
                                          List *exprlist, List *oprlist);
extern bool indexcol_is_bool_constant_for_query(PlannerInfo *root,
                                                IndexOptInfo *index,
                                                int indexcol);
extern bool match_index_to_operand(Node *operand, int indexcol,
                                   IndexOptInfo *index);
extern void check_index_predicates(PlannerInfo *root, RelOptInfo *rel);
 
/*
 * tidpath.c
 *    routines to generate tid paths
 */
extern bool 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 Relids add_outer_joins_to_relids(PlannerInfo *root, Relids input_relids,
                                        SpecialJoinInfo *sjinfo,
                                        List **pushed_down_joins);
extern bool have_join_order_restriction(PlannerInfo *root,
                                        RelOptInfo *rel1, RelOptInfo *rel2);
extern bool have_dangerous_phv(PlannerInfo *root,
                               Relids outer_relids, Relids inner_params);
extern void mark_dummy_rel(RelOptInfo *rel);
extern void init_dummy_sjinfo(SpecialJoinInfo *sjinfo, Relids left_relids,
                              Relids right_relids);
 
/*
 * 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 **p_restrictinfo,
                                JoinDomain *jdomain);
extern Expr *canonicalize_ec_expression(Expr *expr,
                                        Oid req_type, Oid req_collation);
extern void reconsider_outer_join_clauses(PlannerInfo *root);
extern void rebuild_eclass_attr_needed(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 EquivalenceMember *find_ec_member_matching_expr(EquivalenceClass *ec,
                                                       Expr *expr,
                                                       Relids relids);
extern EquivalenceMember *find_computable_ec_member(PlannerInfo *root,
                                                    EquivalenceClass *ec,
                                                    List *exprs,
                                                    Relids relids,
                                                    bool require_parallel_safe);
extern bool relation_can_be_sorted_early(PlannerInfo *root, RelOptInfo *rel,
                                         EquivalenceClass *ec,
                                         bool require_parallel_safe);
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,
                                              SpecialJoinInfo *sjinfo);
extern List *generate_join_implied_equalities_for_ecs(PlannerInfo *root,
                                                      List *eclasses,
                                                      Relids join_relids,
                                                      Relids outer_relids,
                                                      RelOptInfo *inner_rel);
extern bool exprs_known_equal(PlannerInfo *root, Node *item1, Node *item2,
                              Oid opfamily);
extern EquivalenceClass *match_eclasses_to_foreign_key_col(PlannerInfo *root,
                                                           ForeignKeyOptInfo *fkinfo,
                                                           int colno);
extern RestrictInfo *find_derived_clause_for_ec_member(EquivalenceClass *ec,
                                                       EquivalenceMember *em);
extern void add_child_rel_equivalences(PlannerInfo *root,
                                       AppendRelInfo *appinfo,
                                       RelOptInfo *parent_rel,
                                       RelOptInfo *child_rel);
extern void add_child_join_rel_equivalences(PlannerInfo *root,
                                            int nappinfos,
                                            AppendRelInfo **appinfos,
                                            RelOptInfo *parent_joinrel,
                                            RelOptInfo *child_joinrel);
extern void add_setop_child_rel_equivalences(PlannerInfo *root,
                                             RelOptInfo *child_rel,
                                             List *child_tlist,
                                             List *setop_pathkeys);
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(PlannerInfo *root,
                                      EquivalenceClass *eclass,
                                      RelOptInfo *rel);
extern bool is_redundant_derived_clause(RestrictInfo *rinfo, List *clauselist);
extern bool is_redundant_with_indexclauses(RestrictInfo *rinfo,
                                           List *indexclauses);
 
/*
 * 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 bool pathkeys_count_contained_in(List *keys1, List *keys2, int *n_common);
extern List *get_useful_group_keys_orderings(PlannerInfo *root, Path *path);
extern Path *get_cheapest_path_for_pathkeys(List *paths, List *pathkeys,
                                            Relids required_outer,
                                            CostSelector cost_criterion,
                                            bool require_parallel_safe);
extern Path *get_cheapest_fractional_path_for_pathkeys(List *paths,
                                                       List *pathkeys,
                                                       Relids required_outer,
                                                       double fraction);
extern Path *get_cheapest_parallel_safe_total_inner(List *paths);
extern List *build_index_pathkeys(PlannerInfo *root, IndexOptInfo *index,
                                  ScanDirection scandir);
extern List *build_partition_pathkeys(PlannerInfo *root, RelOptInfo *partrel,
                                      ScanDirection scandir, bool *partialkeys);
extern List *build_expression_pathkey(PlannerInfo *root, Expr *expr,
                                      Oid opno,
                                      Relids rel, bool create_it);
extern List *convert_subquery_pathkeys(PlannerInfo *root, RelOptInfo *rel,
                                       List *subquery_pathkeys,
                                       List *subquery_tlist);
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 List *make_pathkeys_for_sortclauses_extended(PlannerInfo *root,
                                                    List **sortclauses,
                                                    List *tlist,
                                                    bool remove_redundant,
                                                    bool remove_group_rtindex,
                                                    bool *sortable,
                                                    bool set_ec_sortref);
extern void initialize_mergeclause_eclasses(PlannerInfo *root,
                                            RestrictInfo *restrictinfo);
extern void update_mergeclause_eclasses(PlannerInfo *root,
                                        RestrictInfo *restrictinfo);
extern List *find_mergeclauses_for_outer_pathkeys(PlannerInfo *root,
                                                  List *pathkeys,
                                                  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 *trim_mergeclauses_for_inner_pathkeys(PlannerInfo *root,
                                                  List *mergeclauses,
                                                  List *pathkeys);
extern List *truncate_useless_pathkeys(PlannerInfo *root,
                                       RelOptInfo *rel,
                                       List *pathkeys);
extern bool has_useful_pathkeys(PlannerInfo *root, RelOptInfo *rel);
extern List *append_pathkeys(List *target, List *source);
extern PathKey *make_canonical_pathkey(PlannerInfo *root,
                                       EquivalenceClass *eclass, Oid opfamily,
                                       int strategy, bool nulls_first);
extern void add_paths_to_append_rel(PlannerInfo *root, RelOptInfo *rel,
                                    List *live_childrels);
 
#endif                          /* PATHS_H */