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Commit8ac6d95

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Cause planner to account for evaluation costs in targetlists and
HAVING quals. Normally this is an insignificant effect --- but itwill not be insignificant when these clauses contain sub-selects.The added costs cannot affect the planning of the query containingthem, but they might have an impact when the query is a sub-queryof a larger one.
1 parentd1686b4 commit8ac6d95

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3 files changed

+79
-6
lines changed

3 files changed

+79
-6
lines changed

‎src/backend/optimizer/plan/createplan.c‎

Lines changed: 53 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -10,7 +10,7 @@
1010
*
1111
*
1212
* IDENTIFICATION
13-
* $Header: /cvsroot/pgsql/src/backend/optimizer/plan/createplan.c,v 1.128 2002/12/12 15:49:32 tgl Exp $
13+
* $Header: /cvsroot/pgsql/src/backend/optimizer/plan/createplan.c,v 1.129 2003/01/13 00:29:25 tgl Exp $
1414
*
1515
*-------------------------------------------------------------------------
1616
*/
@@ -1366,6 +1366,7 @@ make_subqueryscan(List *qptlist,
13661366
SubqueryScan*node=makeNode(SubqueryScan);
13671367
Plan*plan=&node->scan.plan;
13681368

1369+
/* cost is figured here for the convenience of prepunion.c */
13691370
copy_plan_costsize(plan,subplan);
13701371
plan->targetlist=qptlist;
13711372
plan->qual=qpqual;
@@ -1488,7 +1489,7 @@ make_hash(List *tlist, List *hashkeys, Plan *lefttree)
14881489
*/
14891490
plan->startup_cost=plan->total_cost;
14901491
plan->targetlist=tlist;
1491-
plan->qual=NULL;
1492+
plan->qual=NIL;
14921493
plan->lefttree=lefttree;
14931494
plan->righttree=NULL;
14941495
node->hashkeys=hashkeys;
@@ -1646,6 +1647,7 @@ make_agg(Query *root, List *tlist, List *qual,
16461647
Agg*node=makeNode(Agg);
16471648
Plan*plan=&node->plan;
16481649
Pathagg_path;/* dummy for result of cost_agg */
1650+
QualCostqual_cost;
16491651

16501652
node->aggstrategy=aggstrategy;
16511653
node->numCols=numGroupCols;
@@ -1671,6 +1673,27 @@ make_agg(Query *root, List *tlist, List *qual,
16711673
else
16721674
plan->plan_rows=numGroups;
16731675

1676+
/*
1677+
* We also need to account for the cost of evaluation of the qual
1678+
* (ie, the HAVING clause) and the tlist. Note that cost_qual_eval
1679+
* doesn't charge anything for Aggref nodes; this is okay since
1680+
* they are really comparable to Vars.
1681+
*
1682+
* See notes in grouping_planner about why this routine and make_group
1683+
* are the only ones in this file that worry about tlist eval cost.
1684+
*/
1685+
if (qual)
1686+
{
1687+
cost_qual_eval(&qual_cost,qual);
1688+
plan->startup_cost+=qual_cost.startup;
1689+
plan->total_cost+=qual_cost.startup;
1690+
plan->total_cost+=qual_cost.per_tuple*plan->plan_rows;
1691+
}
1692+
cost_qual_eval(&qual_cost,tlist);
1693+
plan->startup_cost+=qual_cost.startup;
1694+
plan->total_cost+=qual_cost.startup;
1695+
plan->total_cost+=qual_cost.per_tuple*plan->plan_rows;
1696+
16741697
plan->qual=qual;
16751698
plan->targetlist=tlist;
16761699
plan->lefttree=lefttree;
@@ -1690,6 +1713,7 @@ make_group(Query *root,
16901713
Group*node=makeNode(Group);
16911714
Plan*plan=&node->plan;
16921715
Pathgroup_path;/* dummy for result of cost_group */
1716+
QualCostqual_cost;
16931717

16941718
node->numCols=numGroupCols;
16951719
node->grpColIdx=grpColIdx;
@@ -1706,7 +1730,23 @@ make_group(Query *root,
17061730
/* One output tuple per estimated result group */
17071731
plan->plan_rows=numGroups;
17081732

1709-
plan->qual=NULL;
1733+
/*
1734+
* We also need to account for the cost of evaluation of the tlist.
1735+
*
1736+
* XXX this double-counts the cost of evaluation of any expressions
1737+
* used for grouping, since in reality those will have been evaluated
1738+
* at a lower plan level and will only be copied by the Group node.
1739+
* Worth fixing?
1740+
*
1741+
* See notes in grouping_planner about why this routine and make_agg
1742+
* are the only ones in this file that worry about tlist eval cost.
1743+
*/
1744+
cost_qual_eval(&qual_cost,tlist);
1745+
plan->startup_cost+=qual_cost.startup;
1746+
plan->total_cost+=qual_cost.startup;
1747+
plan->total_cost+=qual_cost.per_tuple*plan->plan_rows;
1748+
1749+
plan->qual=NIL;
17101750
plan->targetlist=tlist;
17111751
plan->lefttree=lefttree;
17121752
plan->righttree= (Plan*)NULL;
@@ -1718,7 +1758,6 @@ make_group(Query *root,
17181758
* distinctList is a list of SortClauses, identifying the targetlist items
17191759
* that should be considered by the Unique filter.
17201760
*/
1721-
17221761
Unique*
17231762
make_unique(List*tlist,Plan*lefttree,List*distinctList)
17241763
{
@@ -1911,6 +1950,16 @@ make_result(List *tlist,
19111950
plan->plan_width=0;/* XXX try to be smarter? */
19121951
}
19131952

1953+
if (resconstantqual)
1954+
{
1955+
QualCostqual_cost;
1956+
1957+
cost_qual_eval(&qual_cost, (List*)resconstantqual);
1958+
/* resconstantqual is evaluated once at startup */
1959+
plan->startup_cost+=qual_cost.startup+qual_cost.per_tuple;
1960+
plan->total_cost+=qual_cost.startup+qual_cost.per_tuple;
1961+
}
1962+
19141963
plan->targetlist=tlist;
19151964
plan->qual=NIL;
19161965
plan->lefttree=subplan;

‎src/backend/optimizer/plan/planner.c‎

Lines changed: 23 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -8,7 +8,7 @@
88
*
99
*
1010
* IDENTIFICATION
11-
* $Header: /cvsroot/pgsql/src/backend/optimizer/plan/planner.c,v 1.136 2002/12/19 23:25:01 tgl Exp $
11+
* $Header: /cvsroot/pgsql/src/backend/optimizer/plan/planner.c,v 1.137 2003/01/13 00:29:25 tgl Exp $
1212
*
1313
*-------------------------------------------------------------------------
1414
*/
@@ -966,6 +966,7 @@ grouping_planner(Query *parse, double tuple_fraction)
966966
List*sub_tlist;
967967
List*group_pathkeys;
968968
AttrNumber*groupColIdx=NULL;
969+
QualCosttlist_cost;
969970
doublesub_tuple_fraction;
970971
Path*cheapest_path;
971972
Path*sorted_path;
@@ -1452,6 +1453,27 @@ grouping_planner(Query *parse, double tuple_fraction)
14521453
*/
14531454
result_plan->targetlist=sub_tlist;
14541455
}
1456+
/*
1457+
* Also, account for the cost of evaluation of the sub_tlist.
1458+
*
1459+
* Up to now, we have only been dealing with "flat" tlists, containing
1460+
* just Vars. So their evaluation cost is zero according to the
1461+
* model used by cost_qual_eval() (or if you prefer, the cost is
1462+
* factored into cpu_tuple_cost). Thus we can avoid accounting for
1463+
* tlist cost throughout query_planner() and subroutines.
1464+
* But now we've inserted a tlist that might contain actual operators,
1465+
* sub-selects, etc --- so we'd better account for its cost.
1466+
*
1467+
* Below this point, any tlist eval cost for added-on nodes should
1468+
* be accounted for as we create those nodes. Presently, of the
1469+
* node types we can add on, only Agg and Group project new tlists
1470+
* (the rest just copy their input tuples) --- so make_agg() and
1471+
* make_group() are responsible for computing the added cost.
1472+
*/
1473+
cost_qual_eval(&tlist_cost,sub_tlist);
1474+
result_plan->startup_cost+=tlist_cost.startup;
1475+
result_plan->total_cost+=tlist_cost.startup+
1476+
tlist_cost.per_tuple*result_plan->plan_rows;
14551477

14561478
/*
14571479
* Insert AGG or GROUP node if needed, plus an explicit sort step

‎src/backend/optimizer/plan/subselect.c‎

Lines changed: 3 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -7,7 +7,7 @@
77
* Portions Copyright (c) 1994, Regents of the University of California
88
*
99
* IDENTIFICATION
10-
* $Header: /cvsroot/pgsql/src/backend/optimizer/plan/subselect.c,v 1.64 2003/01/12 04:03:34 tgl Exp $
10+
* $Header: /cvsroot/pgsql/src/backend/optimizer/plan/subselect.c,v 1.65 2003/01/13 00:29:26 tgl Exp $
1111
*
1212
*-------------------------------------------------------------------------
1313
*/
@@ -378,6 +378,8 @@ make_subplan(SubLink *slink, List *lefthand)
378378
plan->plan_width);
379379
matplan->startup_cost=matpath.startup_cost;
380380
matplan->total_cost=matpath.total_cost;
381+
matplan->plan_rows=plan->plan_rows;
382+
matplan->plan_width=plan->plan_width;
381383
/* parameter kluge --- see comments above */
382384
matplan->extParam=listCopy(plan->extParam);
383385
matplan->locParam=listCopy(plan->locParam);

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