From 6d6c9fd9a4ade14e29b8629848977a3284fda88e Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Thu, 19 Dec 2002 23:25:01 +0000
Subject: [PATCH] Cause planner to include costs of InitPlans in startup cost
of parent plan node. Not sure why this oversight has persisted so long ...
---
src/backend/optimizer/plan/planner.c | 27 ++++++++++++++++++++-------
1 file changed, 20 insertions(+), 7 deletions(-)
diff --git a/src/backend/optimizer/plan/planner.c b/src/backend/optimizer/plan/planner.c
index b7c0c2ad4b5..e886b88184e 100644
--- a/src/backend/optimizer/plan/planner.c
+++ b/src/backend/optimizer/plan/planner.c
@@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
- * $Header: /cvsroot/pgsql/src/backend/optimizer/plan/planner.c,v 1.135 2002/12/14 00:17:55 tgl Exp $
+ * $Header: /cvsroot/pgsql/src/backend/optimizer/plan/planner.c,v 1.136 2002/12/19 23:25:01 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -264,25 +264,38 @@ subquery_planner(Query *parse, double tuple_fraction)
/*
* If any subplans were generated, or if we're inside a subplan, build
- * subPlan, extParam and locParam lists for plan nodes.
+ * initPlan, extParam and locParam lists for plan nodes.
*/
if (PlannerPlanId != saved_planid || PlannerQueryLevel > 1)
{
+ Cost initplan_cost = 0;
+
+ /* Prepare extParam/locParam data for all nodes in tree */
(void) SS_finalize_plan(plan, parse->rtable);
/*
- * At the moment, SS_finalize_plan doesn't handle initPlans and so
- * we assign them to the topmost plan node.
+ * SS_finalize_plan doesn't handle initPlans, so we have to manually
+ * attach them to the topmost plan node, and add their extParams to
+ * the topmost node's, too.
+ *
+ * We also add the total_cost of each initPlan to the startup cost
+ * of the top node. This is a conservative overestimate, since in
+ * fact each initPlan might be executed later than plan startup, or
+ * even not at all.
*/
plan->initPlan = PlannerInitPlan;
- /* Must add the initPlans' extParams to the topmost node's, too */
+
foreach(lst, plan->initPlan)
{
- SubPlan *subplan = (SubPlan *) lfirst(lst);
+ SubPlan *initplan = (SubPlan *) lfirst(lst);
plan->extParam = set_unioni(plan->extParam,
- subplan->plan->extParam);
+ initplan->plan->extParam);
+ initplan_cost += initplan->plan->total_cost;
}
+
+ plan->startup_cost += initplan_cost;
+ plan->total_cost += initplan_cost;
}
/* Return to outer subquery context */
--
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