postgresql/src/include/optimizer/paths.h
Tom Lane cde35cf4ae Fix eclass_useful_for_merging to give valid results for appendrel children.
Formerly, this function would always return "true" for an appendrel child
relation, because it would think that the appendrel parent was a potential
join target for the child.  In principle that should only lead to some
inefficiency in planning, but fuzz testing by Andreas Seltenreich disclosed
that it could lead to "could not find pathkey item to sort" planner errors
in odd corner cases.  Specifically, we would think that all columns of a
child table's multicolumn index were interesting pathkeys, causing us to
generate a MergeAppend path that sorts by all the columns.  However, if any
of those columns weren't actually used above the level of the appendrel,
they would not get added to that rel's targetlist, which would result in
being unable to resolve the MergeAppend's sort keys against its targetlist
during createplan.c.

Backpatch to 9.3.  In older versions, columns of an appendrel get added
to its targetlist even if they're not mentioned above the scan level,
so that the failure doesn't occur.  It might be worth back-patching this
fix to older versions anyway, but I'll refrain for the moment.
2015-08-06 20:14:53 -04:00

208 lines
7.2 KiB
C

/*-------------------------------------------------------------------------
*
* paths.h
* prototypes for various files in optimizer/path
*
*
* Portions Copyright (c) 1996-2015, 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 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);
#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 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);
/*
* 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,
Relids nullable_relids,
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(PlannerInfo *root,
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 *build_expression_pathkey(PlannerInfo *root, Expr *expr,
Relids nullable_relids, Oid opno,
Relids rel, bool create_it);
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 */