diff options
| -rw-r--r-- | src/backend/optimizer/path/costsize.c | 46 | ||||
| -rw-r--r-- | src/backend/optimizer/plan/subselect.c | 9 | ||||
| -rw-r--r-- | src/include/optimizer/cost.h | 3 |
3 files changed, 49 insertions, 9 deletions
diff --git a/src/backend/optimizer/path/costsize.c b/src/backend/optimizer/path/costsize.c index f76c778998b..d1eb29691a0 100644 --- a/src/backend/optimizer/path/costsize.c +++ b/src/backend/optimizer/path/costsize.c @@ -54,7 +54,7 @@ * Portions Copyright (c) 1994, Regents of the University of California * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/optimizer/path/costsize.c,v 1.185 2007/06/11 01:16:22 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/optimizer/path/costsize.c,v 1.186 2007/09/22 21:36:40 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -2049,9 +2049,10 @@ cost_qual_eval_walker(Node *node, cost_qual_eval_context *context) { /* * Otherwise we will be rescanning the subplan output on each - * evaluation. We need to estimate how much of the output we will - * actually need to scan. NOTE: this logic should agree with the - * estimates used by make_subplan() in plan/subselect.c. + * evaluation. We need to estimate how much of the output we will + * actually need to scan. NOTE: this logic should agree with + * get_initplan_cost, below, and with the estimates used by + * make_subplan() in plan/subselect.c. */ Cost plan_run_cost = plan->total_cost - plan->startup_cost; @@ -2098,6 +2099,43 @@ cost_qual_eval_walker(Node *node, cost_qual_eval_context *context) /* + * get_initplan_cost + * Get the expected cost of evaluating an initPlan. + * + * Keep this in sync with cost_qual_eval_walker's handling of subplans, above, + * and with the estimates used by make_subplan() in plan/subselect.c. + */ +Cost +get_initplan_cost(PlannerInfo *root, SubPlan *subplan) +{ + Cost result; + Plan *plan = planner_subplan_get_plan(root, subplan); + + /* initPlans never use hashtables */ + Assert(!subplan->useHashTable); + /* they are never ALL or ANY, either */ + Assert(!(subplan->subLinkType == ALL_SUBLINK || + subplan->subLinkType == ANY_SUBLINK)); + + if (subplan->subLinkType == EXISTS_SUBLINK) + { + /* we only need to fetch 1 tuple */ + Cost plan_run_cost = plan->total_cost - plan->startup_cost; + + result = plan->startup_cost; + result += plan_run_cost / plan->plan_rows; + } + else + { + /* assume we need all tuples */ + result = plan->total_cost; + } + + return result; +} + + +/* * approx_selectivity * Quick-and-dirty estimation of clause selectivities. * The input can be either an implicitly-ANDed list of boolean diff --git a/src/backend/optimizer/plan/subselect.c b/src/backend/optimizer/plan/subselect.c index 8b739e16d44..76d80bfce0f 100644 --- a/src/backend/optimizer/plan/subselect.c +++ b/src/backend/optimizer/plan/subselect.c @@ -7,7 +7,7 @@ * Portions Copyright (c) 1994, Regents of the University of California * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/optimizer/plan/subselect.c,v 1.124 2007/08/26 21:44:25 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/optimizer/plan/subselect.c,v 1.125 2007/09/22 21:36:40 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -18,6 +18,7 @@ #include "miscadmin.h" #include "nodes/makefuncs.h" #include "optimizer/clauses.h" +#include "optimizer/cost.h" #include "optimizer/planmain.h" #include "optimizer/planner.h" #include "optimizer/subselect.h" @@ -266,7 +267,7 @@ make_subplan(PlannerInfo *root, SubLink *slink, Node *testexpr, bool isTopQual) * (we're only expecting one row out, anyway). * * NOTE: if you change these numbers, also change cost_qual_eval_walker() - * in path/costsize.c. + * and get_initplan_cost() in path/costsize.c. * * XXX If an ALL/ANY subplan is uncorrelated, we may decide to hash or * materialize its result below. In that case it would've been better to @@ -1021,7 +1022,7 @@ SS_finalize_plan(PlannerInfo *root, Plan *plan) * have extParams that are setParams of other initPlans, so we have to * take care of this situation explicitly.) * - * We also add the total_cost of each initPlan to the startup cost of the + * We also add the eval 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. */ @@ -1041,7 +1042,7 @@ SS_finalize_plan(PlannerInfo *root, Plan *plan) { initSetParam = bms_add_member(initSetParam, lfirst_int(l2)); } - initplan_cost += initplan->total_cost; + initplan_cost += get_initplan_cost(root, initsubplan); } /* allParam must include all these params */ plan->allParam = bms_add_members(plan->allParam, initExtParam); diff --git a/src/include/optimizer/cost.h b/src/include/optimizer/cost.h index dc052dcf55f..22034850148 100644 --- a/src/include/optimizer/cost.h +++ b/src/include/optimizer/cost.h @@ -7,7 +7,7 @@ * Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * - * $PostgreSQL: pgsql/src/include/optimizer/cost.h,v 1.88 2007/07/25 12:22:53 mha Exp $ + * $PostgreSQL: pgsql/src/include/optimizer/cost.h,v 1.89 2007/09/22 21:36:40 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -92,6 +92,7 @@ extern void cost_mergejoin(MergePath *path, PlannerInfo *root); extern void cost_hashjoin(HashPath *path, PlannerInfo *root); extern void cost_qual_eval(QualCost *cost, List *quals, PlannerInfo *root); extern void cost_qual_eval_node(QualCost *cost, Node *qual, PlannerInfo *root); +extern Cost get_initplan_cost(PlannerInfo *root, SubPlan *subplan); extern void set_baserel_size_estimates(PlannerInfo *root, RelOptInfo *rel); extern void set_joinrel_size_estimates(PlannerInfo *root, RelOptInfo *rel, RelOptInfo *outer_rel, |