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Use parameterized paths to generate inner indexscans more flexibly.

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This patch fixes the planner so that it can generate nestloop-with-
inner-indexscan plans even with one or more levels of joining between
the indexscan and the nestloop join that is supplying the parameter.
The executor was fixed to handle such cases some time ago, but the
planner was not ready.  This should improve our plans in many situations
where join ordering restrictions formerly forced complete table scans.

There is probably a fair amount of tuning work yet to be done, because
of various heuristics that have been added to limit the number of
parameterized paths considered.  However, we are not going to find out
what needs to be adjusted until the code gets some real-world use, so
it's time to get it in there where it can be tested easily.

Note API change for index AM amcostestimate functions.  I'm not aware of
any non-core index AMs, but if there are any, they will need minor
adjustments.
This commit is contained in:
Tom Lane
2012-01-27 19:26:38 -05:00
parent b376ec6fa5
commit e2fa76d80b
26 changed files with 3884 additions and 2292 deletions
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21
src/include/optimizer/paths.h
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@@ -44,17 +44,14 @@ extern void debug_print_rel(PlannerInfo *root, RelOptInfo *rel);
*/
extern void create_index_paths(PlannerInfo *root, RelOptInfo *rel);
extern List *generate_bitmap_or_paths(PlannerInfo *root, RelOptInfo *rel,
List *clauses, List *outer_clauses,
RelOptInfo *outer_rel);
extern void best_inner_indexscan(PlannerInfo *root, RelOptInfo *rel,
RelOptInfo *outer_rel, JoinType jointype,
Path **cheapest_startup, Path **cheapest_total);
List *clauses, List *other_clauses,
bool restriction_only);
extern bool relation_has_unique_index_for(PlannerInfo *root, RelOptInfo *rel,
List *restrictlist,
List *exprlist, List *oprlist);
extern bool eclass_matches_any_index(EquivalenceClass *ec,
EquivalenceMember *em,
RelOptInfo *rel);
extern bool eclass_member_matches_indexcol(EquivalenceClass *ec,
EquivalenceMember *em,
IndexOptInfo *index, int indexcol);
extern bool match_index_to_operand(Node *operand, int indexcol,
IndexOptInfo *index);
extern void expand_indexqual_conditions(IndexOptInfo *index,
@@ -127,9 +124,9 @@ extern void add_child_rel_equivalences(PlannerInfo *root,
extern void mutate_eclass_expressions(PlannerInfo *root,
Node *(*mutator) (),
void *context);
extern List *find_eclass_clauses_for_index_join(PlannerInfo *root,
RelOptInfo *rel,
Relids outer_relids);
extern List *generate_implied_equalities_for_indexcol(PlannerInfo *root,
IndexOptInfo *index,
int indexcol);
extern bool have_relevant_eclass_joinclause(PlannerInfo *root,
RelOptInfo *rel1, RelOptInfo *rel2);
extern bool has_relevant_eclass_joinclause(PlannerInfo *root,
@@ -153,9 +150,11 @@ extern List *canonicalize_pathkeys(PlannerInfo *root, List *pathkeys);
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);