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1a8d5afb0d
In place of three separate but interrelated lists (indexclauses, indexquals, and indexqualcols), an IndexPath now has one list "indexclauses" of IndexClause nodes. This holds basically the same information as before, but in a more useful format: in particular, there is now a clear connection between an indexclause (an original restriction clause from WHERE or JOIN/ON) and the indexquals (directly usable index conditions) derived from it. We also change the ground rules a bit by mandating that clause commutation, if needed, be done up-front so that what is stored in the indexquals list is always directly usable as an index condition. This gets rid of repeated re-determination of which side of the clause is the indexkey during costing and plan generation, as well as repeated lookups of the commutator operator. To minimize the added up-front cost, the typical case of commuting a plain OpExpr is handled by a new special-purpose function commute_restrictinfo(). For RowCompareExprs, generating the new clause properly commuted to begin with is not really any more complex than before, it's just different --- and we can save doing that work twice, as the pretty-klugy original implementation did. Tracking the connection between original and derived clauses lets us also track explicitly whether the derived clauses are an exact or lossy translation of the original. This provides a cheap solution to getting rid of unnecessary rechecks of boolean index clauses, which previously seemed like it'd be more expensive than it was worth. Another pleasant (IMO) side-effect is that EXPLAIN now always shows index clauses with the indexkey on the left; this seems less confusing. This commit leaves expand_indexqual_conditions() and some related functions in a slightly messy state. I didn't bother to change them any more than minimally necessary to work with the new data structure, because all that code is going to be refactored out of existence in a follow-on patch. Discussion: https://postgr.es/m/22182.1549124950@sss.pgh.pa.us
238 lines
8.6 KiB
C
238 lines
8.6 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) 1996-2019, 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/pathnodes.h"
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/*
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* allpaths.c
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*/
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extern PGDLLIMPORT bool enable_geqo;
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extern PGDLLIMPORT int geqo_threshold;
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extern PGDLLIMPORT int min_parallel_table_scan_size;
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extern PGDLLIMPORT int min_parallel_index_scan_size;
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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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JoinType jointype,
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JoinPathExtraData *extra);
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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 void set_dummy_rel_pathlist(RelOptInfo *rel);
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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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extern void generate_gather_paths(PlannerInfo *root, RelOptInfo *rel,
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bool override_rows);
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extern int compute_parallel_worker(RelOptInfo *rel, double heap_pages,
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double index_pages, int max_workers);
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extern void create_partial_bitmap_paths(PlannerInfo *root, RelOptInfo *rel,
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Path *bitmapqual);
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extern void generate_partitionwise_join_paths(PlannerInfo *root,
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RelOptInfo *rel);
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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 indexcol_is_bool_constant_for_query(IndexOptInfo *index,
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int indexcol);
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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 check_index_predicates(PlannerInfo *root, RelOptInfo *rel);
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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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extern bool have_dangerous_phv(PlannerInfo *root,
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Relids outer_relids, Relids inner_params);
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extern void mark_dummy_rel(RelOptInfo *rel);
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extern bool have_partkey_equi_join(RelOptInfo *joinrel,
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RelOptInfo *rel1, RelOptInfo *rel2,
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JoinType jointype, List *restrictlist);
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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,
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RestrictInfo **p_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 List *generate_join_implied_equalities_for_ecs(PlannerInfo *root,
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List *eclasses,
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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 EquivalenceClass *match_eclasses_to_foreign_key_col(PlannerInfo *root,
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ForeignKeyOptInfo *fkinfo,
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int colno);
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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 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(PlannerInfo *root,
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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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extern bool is_redundant_with_indexclauses(RestrictInfo *rinfo,
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List *indexclauses);
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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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bool require_parallel_safe);
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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 Path *get_cheapest_parallel_safe_total_inner(List *paths);
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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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List *subquery_tlist);
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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_outer_pathkeys(PlannerInfo *root,
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List *pathkeys,
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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 *trim_mergeclauses_for_inner_pathkeys(PlannerInfo *root,
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List *mergeclauses,
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List *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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extern PathKey *make_canonical_pathkey(PlannerInfo *root,
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EquivalenceClass *eclass, Oid opfamily,
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int strategy, bool nulls_first);
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extern void add_paths_to_append_rel(PlannerInfo *root, RelOptInfo *rel,
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List *live_childrels);
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#endif /* PATHS_H */
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