database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-10-16 17:07:43 +03:00
Code Activity

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

Browse Source 
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

7
src/backend/optimizer/plan/createplan.c
View File

@@ -10,7 +10,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/optimizer/plan/createplan.c,v 1.243 2008/08/07 03:04:03 tgl Exp $
* $PostgreSQL: pgsql/src/backend/optimizer/plan/createplan.c,v 1.244 2008/08/07 19:35:02 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -3109,8 +3109,8 @@ make_unique(Plan *lefttree, List *distinctList)
*/
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)
{
SetOp *node = makeNode(SetOp);
Plan *plan = &node->plan;
@@ -3159,6 +3159,7 @@ make_setop(SetOpCmd cmd, SetOpStrategy strategy, Plan *lefttree,
node->dupColIdx = dupColIdx;
node->dupOperators = dupOperators;
node->flagColIdx = flagColIdx;
node->firstFlag = firstFlag;
node->numGroups = numGroups;
return node;