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73fc2e5bab
Previously, pull_varnos() took the relids of a PlaceHolderVar as being
equal to the relids in its contents, but that fails to account for the
possibility that we have to postpone evaluation of the PHV due to outer
joins. This could result in a malformed plan. The known cases end up
triggering the "failed to assign all NestLoopParams to plan nodes"
sanity check in createplan.c, but other symptoms may be possible.
The right value to use is the join level we actually intend to evaluate
the PHV at. We can get that from the ph_eval_at field of the associated
PlaceHolderInfo. However, there are some places that call pull_varnos()
before the PlaceHolderInfos have been created; in that case, fall back
to the conservative assumption that the PHV will be evaluated at its
syntactic level. (In principle this might result in missing some legal
optimization, but I'm not aware of any cases where it's an issue in
practice.) Things are also a bit ticklish for calls occurring during
deconstruct_jointree(), but AFAICS the ph_eval_at fields should have
reached their final values by the time we need them.
The main problem in making this work is that pull_varnos() has no
way to get at the PlaceHolderInfos. We can fix that easily, if a
bit tediously, in HEAD by passing it the planner "root" pointer.
In the back branches that'd cause an unacceptable API/ABI break for
extensions, so leave the existing entry points alone and add new ones
with the additional parameter. (If an old entry point is called and
encounters a PHV, it'll fall back to using the syntactic level,
again possibly missing some valid optimization.)
Back-patch to v12. The computation is surely also wrong before that,
but it appears that we cannot reach a bad plan thanks to join order
restrictions imposed on the subquery that the PlaceHolderVar came from.
The error only became reachable when commit 4be058fe9 allowed trivial
subqueries to be collapsed out completely, eliminating their join order
restrictions.
Per report from Stephan Springl.
Discussion: https://postgr.es/m/171041.1610849523@sss.pgh.pa.us
249 lines
9.4 KiB
C
249 lines
9.4 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) 1996-2020, 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 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 void generate_useful_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(PlannerInfo *root,
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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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/*
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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 Expr *find_em_expr_for_rel(EquivalenceClass *ec, RelOptInfo *rel);
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extern Expr *find_em_expr_usable_for_sorting_rel(PlannerInfo *root,
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EquivalenceClass *ec,
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RelOptInfo *rel,
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bool require_parallel_safe);
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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 void add_child_join_rel_equivalences(PlannerInfo *root,
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int nappinfos,
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AppendRelInfo **appinfos,
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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 bool pathkeys_count_contained_in(List *keys1, List *keys2, int *n_common);
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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_partition_pathkeys(PlannerInfo *root, RelOptInfo *partrel,
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ScanDirection scandir, bool *partialkeys);
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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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