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Account for SRFs in targetlists in planner rowcount estimates.

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We made use of the ROWS estimate for set-returning functions used in FROM,
but not for those used in SELECT targetlists; which is a bit of an
oversight considering there are common usages that require the latter
approach.  Improve that.  (I had initially thought it might be worth
folding this into cost_qual_eval, but after investigation concluded that
that wouldn't be very helpful, so just do it separately.)  Per complaint
from David Johnston.

Back-patch to 9.2, but not further, for fear of destabilizing plan choices
in existing releases.
This commit is contained in:
Tom Lane
2012-07-21 17:45:07 -04:00
parent ed0af33247
commit 31c7c642b6
7 changed files with 120 additions and 48 deletions
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29
src/backend/optimizer/plan/createplan.c
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@ -30,6 +30,7 @@
#include "optimizer/placeholder.h"
#include "optimizer/plancat.h"
#include "optimizer/planmain.h"
#include "optimizer/planner.h"
#include "optimizer/predtest.h"
#include "optimizer/restrictinfo.h"
#include "optimizer/subselect.h"
@ -4126,8 +4127,8 @@ make_agg(PlannerInfo *root, List *tlist, List *qual,
* anything for Aggref nodes; this is okay since they are really
* comparable to Vars.
*
* See notes in grouping_planner about why only make_agg, make_windowagg
* and make_group worry about tlist eval cost.
* See notes in add_tlist_costs_to_plan about why only make_agg,
* make_windowagg and make_group worry about tlist eval cost.
*/
if (qual)
{
@ -4136,10 +4137,7 @@ make_agg(PlannerInfo *root, List *tlist, List *qual,
plan->total_cost += qual_cost.startup;
plan->total_cost += qual_cost.per_tuple * plan->plan_rows;
}
cost_qual_eval(&qual_cost, tlist, root);
plan->startup_cost += qual_cost.startup;
plan->total_cost += qual_cost.startup;
plan->total_cost += qual_cost.per_tuple * plan->plan_rows;
add_tlist_costs_to_plan(root, plan, tlist);
plan->qual = qual;
plan->targetlist = tlist;
@ -4160,7 +4158,6 @@ make_windowagg(PlannerInfo *root, List *tlist,
WindowAgg *node = makeNode(WindowAgg);
Plan *plan = &node->plan;
Path windowagg_path; /* dummy for result of cost_windowagg */
QualCost qual_cost;
node->winref = winref;
node->partNumCols = partNumCols;
@ -4185,13 +4182,10 @@ make_windowagg(PlannerInfo *root, List *tlist,
/*
* We also need to account for the cost of evaluation of the tlist.
*
* See notes in grouping_planner about why only make_agg, make_windowagg
* and make_group worry about tlist eval cost.
* See notes in add_tlist_costs_to_plan about why only make_agg,
* make_windowagg and make_group worry about tlist eval cost.
*/
cost_qual_eval(&qual_cost, tlist, root);
plan->startup_cost += qual_cost.startup;
plan->total_cost += qual_cost.startup;
plan->total_cost += qual_cost.per_tuple * plan->plan_rows;
add_tlist_costs_to_plan(root, plan, tlist);
plan->targetlist = tlist;
plan->lefttree = lefttree;
@ -4242,8 +4236,8 @@ make_group(PlannerInfo *root,
* lower plan level and will only be copied by the Group node. Worth
* fixing?
*
* See notes in grouping_planner about why only make_agg, make_windowagg
* and make_group worry about tlist eval cost.
* See notes in add_tlist_costs_to_plan about why only make_agg,
* make_windowagg and make_group worry about tlist eval cost.
*/
if (qual)
{
@ -4252,10 +4246,7 @@ make_group(PlannerInfo *root,
plan->total_cost += qual_cost.startup;
plan->total_cost += qual_cost.per_tuple * plan->plan_rows;
}
cost_qual_eval(&qual_cost, tlist, root);
plan->startup_cost += qual_cost.startup;
plan->total_cost += qual_cost.startup;
plan->total_cost += qual_cost.per_tuple * plan->plan_rows;
add_tlist_costs_to_plan(root, plan, tlist);
plan->qual = qual;
plan->targetlist = tlist;