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Planner speedup hacking. Avoid saving useless pathkeys, so that path

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comparison does not consider paths different when they differ only in
uninteresting aspects of sort order.  (We had a special case of this
consideration for indexscans already, but generalize it to apply to
ordered join paths too.)  Be stricter about what is a canonical pathkey
to allow faster pathkey comparison.  Cache canonical pathkeys and
dispersion stats for left and right sides of a RestrictInfo's clause,
to avoid repeated computation.  Total speedup will depend on number of
tables in a query, but I see about 4x speedup of planning phase for
a sample seven-table query.
This commit is contained in:
Tom Lane
2000-12-14 22:30:45 +00:00
parent db11f4382a
commit ea166f1146
16 changed files with 622 additions and 365 deletions
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3
src/include/optimizer/pathnode.h
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@@ -7,7 +7,7 @@
* Portions Copyright (c) 1996-2000, PostgreSQL, Inc
* Portions Copyright (c) 1994, Regents of the University of California
*
* $Id: pathnode.h,v 1.31 2000/11/12 00:37:01 tgl Exp $
* $Id: pathnode.h,v 1.32 2000/12/14 22:30:45 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -30,6 +30,7 @@ extern Path *create_seqscan_path(RelOptInfo *rel);
extern IndexPath *create_index_path(Query *root, RelOptInfo *rel,
IndexOptInfo *index,
List *restriction_clauses,
List *pathkeys,
ScanDirection indexscandir);
extern TidPath *create_tidscan_path(RelOptInfo *rel, List *tideval);
extern AppendPath *create_append_path(RelOptInfo *rel, List *subpaths);

27
src/include/optimizer/paths.h
View File

@@ -8,7 +8,7 @@
* Portions Copyright (c) 1996-2000, PostgreSQL, Inc
* Portions Copyright (c) 1994, Regents of the University of California
*
* $Id: paths.h,v 1.48 2000/09/29 18:21:40 tgl Exp $
* $Id: paths.h,v 1.49 2000/12/14 22:30:45 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -34,9 +34,7 @@ extern RelOptInfo *make_fromexpr_rel(Query *root, FromExpr *from);
* indxpath.c
* routines to generate index paths
*/
extern void create_index_paths(Query *root, RelOptInfo *rel, List *indices,
List *restrictinfo_list,
List *joininfo_list);
extern void create_index_paths(Query *root, RelOptInfo *rel, List *indices);
extern Oid indexable_operator(Expr *clause, Oid opclass, Oid relam,
bool indexkey_on_left);
extern List *extract_or_indexqual_conditions(RelOptInfo *rel,
@@ -97,6 +95,9 @@ extern void generate_implied_equalities(Query *root);
extern List *canonicalize_pathkeys(Query *root, List *pathkeys);
extern PathKeysComparison compare_pathkeys(List *keys1, List *keys2);
extern bool pathkeys_contained_in(List *keys1, List *keys2);
extern PathKeysComparison compare_noncanonical_pathkeys(List *keys1,
List *keys2);
extern bool noncanonical_pathkeys_contained_in(List *keys1, List *keys2);
extern Path *get_cheapest_path_for_pathkeys(List *paths, List *pathkeys,
CostSelector cost_criterion);
extern Path *get_cheapest_fractional_path_for_pathkeys(List *paths,
@@ -105,15 +106,23 @@ extern Path *get_cheapest_fractional_path_for_pathkeys(List *paths,
extern List *build_index_pathkeys(Query *root, RelOptInfo *rel,
IndexOptInfo *index,
ScanDirection scandir);
extern List *build_join_pathkeys(List *outer_pathkeys,
List *join_rel_tlist,
List *equi_key_list);
extern List *build_join_pathkeys(Query *root,
RelOptInfo *joinrel,
List *outer_pathkeys);
extern List *make_pathkeys_for_sortclauses(List *sortclauses,
List *tlist);
extern List *find_mergeclauses_for_pathkeys(List *pathkeys,
List *restrictinfos);
extern List *find_mergeclauses_for_pathkeys(Query *root,
List *pathkeys,
List *restrictinfos);
extern List *make_pathkeys_for_mergeclauses(Query *root,
List *mergeclauses,
RelOptInfo *rel);
extern int pathkeys_useful_for_merging(Query *root,
RelOptInfo *rel,
List *pathkeys);
extern int pathkeys_useful_for_ordering(Query *root, List *pathkeys);
extern List *truncate_useless_pathkeys(Query *root,
RelOptInfo *rel,
List *pathkeys);
#endif /* PATHS_H */