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e7cb7ee145
Foreign data wrappers can use this capability for so-called "join pushdown"; that is, instead of executing two separate foreign scans and then joining the results locally, they can generate a path which performs the join on the remote server and then is scanned locally. This commit does not extend postgres_fdw to take advantage of this capability; it just provides the infrastructure. Custom scan providers can use this in a similar way. Previously, it was only possible for a custom scan provider to scan a single relation. Now, it can scan an entire join tree, provided of course that it knows how to produce the same results that the join would have produced if executed normally. KaiGai Kohei, reviewed by Shigeru Hanada, Ashutosh Bapat, and me.
212 lines
7.3 KiB
C
212 lines
7.3 KiB
C
/*-------------------------------------------------------------------------
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*
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* paths.h
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* prototypes for various files in optimizer/path
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*
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*
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* Portions Copyright (c) 1996-2015, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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* src/include/optimizer/paths.h
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*
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*-------------------------------------------------------------------------
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*/
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#ifndef PATHS_H
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#define PATHS_H
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#include "nodes/relation.h"
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/*
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* allpaths.c
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*/
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extern bool enable_geqo;
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extern int geqo_threshold;
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/* Hook for plugins to get control in set_rel_pathlist() */
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typedef void (*set_rel_pathlist_hook_type) (PlannerInfo *root,
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RelOptInfo *rel,
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Index rti,
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RangeTblEntry *rte);
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extern PGDLLIMPORT set_rel_pathlist_hook_type set_rel_pathlist_hook;
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/* Hook for plugins to get control in add_paths_to_joinrel() */
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typedef void (*set_join_pathlist_hook_type) (PlannerInfo *root,
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RelOptInfo *joinrel,
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RelOptInfo *outerrel,
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RelOptInfo *innerrel,
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List *restrictlist,
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JoinType jointype,
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SpecialJoinInfo *sjinfo,
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SemiAntiJoinFactors *semifactors,
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Relids param_source_rels,
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Relids extra_lateral_rels);
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extern PGDLLIMPORT set_join_pathlist_hook_type set_join_pathlist_hook;
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/* Hook for plugins to replace standard_join_search() */
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typedef RelOptInfo *(*join_search_hook_type) (PlannerInfo *root,
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int levels_needed,
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List *initial_rels);
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extern PGDLLIMPORT join_search_hook_type join_search_hook;
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extern RelOptInfo *make_one_rel(PlannerInfo *root, List *joinlist);
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extern RelOptInfo *standard_join_search(PlannerInfo *root, int levels_needed,
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List *initial_rels);
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#ifdef OPTIMIZER_DEBUG
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extern void debug_print_rel(PlannerInfo *root, RelOptInfo *rel);
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#endif
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/*
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* indxpath.c
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* routines to generate index paths
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*/
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extern void create_index_paths(PlannerInfo *root, RelOptInfo *rel);
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extern bool relation_has_unique_index_for(PlannerInfo *root, RelOptInfo *rel,
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List *restrictlist,
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List *exprlist, List *oprlist);
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extern bool match_index_to_operand(Node *operand, int indexcol,
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IndexOptInfo *index);
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extern void expand_indexqual_conditions(IndexOptInfo *index,
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List *indexclauses, List *indexclausecols,
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List **indexquals_p, List **indexqualcols_p);
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extern void check_partial_indexes(PlannerInfo *root, RelOptInfo *rel);
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extern Expr *adjust_rowcompare_for_index(RowCompareExpr *clause,
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IndexOptInfo *index,
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int indexcol,
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List **indexcolnos,
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bool *var_on_left_p);
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/*
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* tidpath.h
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* routines to generate tid paths
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*/
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extern void create_tidscan_paths(PlannerInfo *root, RelOptInfo *rel);
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/*
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* joinpath.c
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* routines to create join paths
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*/
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extern void add_paths_to_joinrel(PlannerInfo *root, RelOptInfo *joinrel,
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RelOptInfo *outerrel, RelOptInfo *innerrel,
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JoinType jointype, SpecialJoinInfo *sjinfo,
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List *restrictlist);
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/*
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* joinrels.c
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* routines to determine which relations to join
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*/
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extern void join_search_one_level(PlannerInfo *root, int level);
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extern RelOptInfo *make_join_rel(PlannerInfo *root,
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RelOptInfo *rel1, RelOptInfo *rel2);
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extern bool have_join_order_restriction(PlannerInfo *root,
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RelOptInfo *rel1, RelOptInfo *rel2);
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/*
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* equivclass.c
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* routines for managing EquivalenceClasses
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*/
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typedef bool (*ec_matches_callback_type) (PlannerInfo *root,
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RelOptInfo *rel,
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EquivalenceClass *ec,
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EquivalenceMember *em,
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void *arg);
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extern bool process_equivalence(PlannerInfo *root, RestrictInfo *restrictinfo,
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bool below_outer_join);
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extern Expr *canonicalize_ec_expression(Expr *expr,
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Oid req_type, Oid req_collation);
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extern void reconsider_outer_join_clauses(PlannerInfo *root);
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extern EquivalenceClass *get_eclass_for_sort_expr(PlannerInfo *root,
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Expr *expr,
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Relids nullable_relids,
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List *opfamilies,
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Oid opcintype,
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Oid collation,
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Index sortref,
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Relids rel,
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bool create_it);
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extern void generate_base_implied_equalities(PlannerInfo *root);
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extern List *generate_join_implied_equalities(PlannerInfo *root,
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Relids join_relids,
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Relids outer_relids,
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RelOptInfo *inner_rel);
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extern bool exprs_known_equal(PlannerInfo *root, Node *item1, Node *item2);
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extern void add_child_rel_equivalences(PlannerInfo *root,
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AppendRelInfo *appinfo,
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RelOptInfo *parent_rel,
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RelOptInfo *child_rel);
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extern void mutate_eclass_expressions(PlannerInfo *root,
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Node *(*mutator) (),
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void *context,
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bool include_child_exprs);
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extern List *generate_implied_equalities_for_column(PlannerInfo *root,
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RelOptInfo *rel,
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ec_matches_callback_type callback,
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void *callback_arg,
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Relids prohibited_rels);
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extern bool have_relevant_eclass_joinclause(PlannerInfo *root,
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RelOptInfo *rel1, RelOptInfo *rel2);
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extern bool has_relevant_eclass_joinclause(PlannerInfo *root,
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RelOptInfo *rel1);
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extern bool eclass_useful_for_merging(EquivalenceClass *eclass,
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RelOptInfo *rel);
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extern bool is_redundant_derived_clause(RestrictInfo *rinfo, List *clauselist);
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/*
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* pathkeys.c
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* utilities for matching and building path keys
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*/
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typedef enum
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{
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PATHKEYS_EQUAL, /* pathkeys are identical */
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PATHKEYS_BETTER1, /* pathkey 1 is a superset of pathkey 2 */
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PATHKEYS_BETTER2, /* vice versa */
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PATHKEYS_DIFFERENT /* neither pathkey includes the other */
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} PathKeysComparison;
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extern PathKeysComparison compare_pathkeys(List *keys1, List *keys2);
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extern bool pathkeys_contained_in(List *keys1, List *keys2);
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extern Path *get_cheapest_path_for_pathkeys(List *paths, List *pathkeys,
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Relids required_outer,
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CostSelector cost_criterion);
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extern Path *get_cheapest_fractional_path_for_pathkeys(List *paths,
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List *pathkeys,
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Relids required_outer,
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double fraction);
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extern List *build_index_pathkeys(PlannerInfo *root, IndexOptInfo *index,
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ScanDirection scandir);
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extern List *build_expression_pathkey(PlannerInfo *root, Expr *expr,
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Relids nullable_relids, Oid opno,
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Relids rel, bool create_it);
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extern List *convert_subquery_pathkeys(PlannerInfo *root, RelOptInfo *rel,
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List *subquery_pathkeys);
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extern List *build_join_pathkeys(PlannerInfo *root,
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RelOptInfo *joinrel,
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JoinType jointype,
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List *outer_pathkeys);
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extern List *make_pathkeys_for_sortclauses(PlannerInfo *root,
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List *sortclauses,
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List *tlist);
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extern void initialize_mergeclause_eclasses(PlannerInfo *root,
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RestrictInfo *restrictinfo);
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extern void update_mergeclause_eclasses(PlannerInfo *root,
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RestrictInfo *restrictinfo);
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extern List *find_mergeclauses_for_pathkeys(PlannerInfo *root,
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List *pathkeys,
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bool outer_keys,
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List *restrictinfos);
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extern List *select_outer_pathkeys_for_merge(PlannerInfo *root,
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List *mergeclauses,
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RelOptInfo *joinrel);
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extern List *make_inner_pathkeys_for_merge(PlannerInfo *root,
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List *mergeclauses,
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List *outer_pathkeys);
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extern List *truncate_useless_pathkeys(PlannerInfo *root,
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RelOptInfo *rel,
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List *pathkeys);
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extern bool has_useful_pathkeys(PlannerInfo *root, RelOptInfo *rel);
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#endif /* PATHS_H */
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