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Improve INTERSECT/EXCEPT hashing by realizing that we don't need to make any

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hashtable entries for tuples that are found only in the second input: they
can never contribute to the output.  Furthermore, this implies that the
planner should endeavor to put first the smaller (in number of groups) input
relation for an INTERSECT.  Implement that, and upgrade prepunion's estimation
of the number of rows returned by setops so that there's some amount of sanity
in the estimate of which one is smaller.
This commit is contained in:
Tom Lane
2008-08-07 19:35:02 +00:00
parent 368df30427
commit af95d7aa63
9 changed files with 278 additions and 159 deletions
Download Patch File Download Diff File Expand all files Collapse all files

6
src/include/optimizer/planmain.h
View File

@@ -7,7 +7,7 @@
* Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* $PostgreSQL: pgsql/src/include/optimizer/planmain.h,v 1.109 2008/08/07 03:04:04 tgl Exp $
* $PostgreSQL: pgsql/src/include/optimizer/planmain.h,v 1.110 2008/08/07 19:35:02 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -62,8 +62,8 @@ extern Unique *make_unique(Plan *lefttree, List *distinctList);
extern Limit *make_limit(Plan *lefttree, Node *limitOffset, Node *limitCount,
int64 offset_est, int64 count_est);
extern SetOp *make_setop(SetOpCmd cmd, SetOpStrategy strategy, Plan *lefttree,
List *distinctList, AttrNumber flagColIdx, long numGroups,
double outputRows);
List *distinctList, AttrNumber flagColIdx, int firstFlag,
long numGroups, double outputRows);
extern Result *make_result(PlannerInfo *root, List *tlist,
Node *resconstantqual, Plan *subplan);
extern bool is_projection_capable_plan(Plan *plan);

7
src/include/optimizer/tlist.h
View File

@@ -7,7 +7,7 @@
* Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* $PostgreSQL: pgsql/src/include/optimizer/tlist.h,v 1.51 2008/08/07 01:11:52 tgl Exp $
* $PostgreSQL: pgsql/src/include/optimizer/tlist.h,v 1.52 2008/08/07 19:35:02 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -23,6 +23,9 @@ extern TargetEntry *tlist_member_ignore_relabel(Node *node, List *targetlist);
extern List *flatten_tlist(List *tlist);
extern List *add_to_flat_tlist(List *tlist, List *vars);
extern List *get_tlist_exprs(List *tlist, bool includeJunk);
extern bool tlist_same_datatypes(List *tlist, List *colTypes, bool junkOK);
extern TargetEntry *get_sortgroupref_tle(Index sortref,
List *targetList);
extern TargetEntry *get_sortgroupclause_tle(SortGroupClause *sgClause,
@@ -37,6 +40,4 @@ extern AttrNumber *extract_grouping_cols(List *groupClause, List *tlist);
extern bool grouping_is_sortable(List *groupClause);
extern bool grouping_is_hashable(List *groupClause);
extern bool tlist_same_datatypes(List *tlist, List *colTypes, bool junkOK);
#endif /* TLIST_H */