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Avoid making a separate pass over the query to check for partializability.

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It's rather silly to make a separate pass over the tlist + HAVING qual,
and a separate set of visits to the syscache, when get_agg_clause_costs
already has all the required information in hand.  This nets out as less
code as well as fewer cycles.
This commit is contained in:
Tom Lane
2016-06-26 15:55:01 -04:00
parent 19e972d558
commit f1993038a4
4 changed files with 54 additions and 118 deletions
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29
src/backend/optimizer/plan/planner.c
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@ -110,8 +110,10 @@ static double get_number_of_groups(PlannerInfo *root,
List *rollup_groupclauses);
static void set_grouped_rel_consider_parallel(PlannerInfo *root,
RelOptInfo *grouped_rel,
PathTarget *target);
static Size estimate_hashagg_tablesize(Path *path, AggClauseCosts *agg_costs,
PathTarget *target,
const AggClauseCosts *agg_costs);
static Size estimate_hashagg_tablesize(Path *path,
const AggClauseCosts *agg_costs,
double dNumGroups);
static RelOptInfo *create_grouping_paths(PlannerInfo *root,
RelOptInfo *input_rel,
@ -3207,7 +3209,8 @@ get_number_of_groups(PlannerInfo *root,
*/
static void
set_grouped_rel_consider_parallel(PlannerInfo *root, RelOptInfo *grouped_rel,
PathTarget *target)
PathTarget *target,
const AggClauseCosts *agg_costs)
{
Query *parse = root->parse;
@ -3240,15 +3243,14 @@ set_grouped_rel_consider_parallel(PlannerInfo *root, RelOptInfo *grouped_rel,
return;
/*
* All that's left to check now is to make sure all aggregate functions
* support partial mode. If there's no aggregates then we can skip
* checking that.
* If we have any non-partial-capable aggregates, or if any of them can't
* be serialized, we can't go parallel.
*/
if (!parse->hasAggs)
grouped_rel->consider_parallel = true;
else if (aggregates_allow_partial((Node *) target->exprs) == PAT_ANY &&
aggregates_allow_partial(root->parse->havingQual) == PAT_ANY)
grouped_rel->consider_parallel = true;
if (agg_costs->hasNonPartial || agg_costs->hasNonSerial)
return;
/* OK, consider parallelization */
grouped_rel->consider_parallel = true;
}
/*
@ -3257,7 +3259,7 @@ set_grouped_rel_consider_parallel(PlannerInfo *root, RelOptInfo *grouped_rel,
* require based on the agg_costs, path width and dNumGroups.
*/
static Size
estimate_hashagg_tablesize(Path *path, AggClauseCosts *agg_costs,
estimate_hashagg_tablesize(Path *path, const AggClauseCosts *agg_costs,
double dNumGroups)
{
Size hashentrysize;
@ -3411,7 +3413,8 @@ create_grouping_paths(PlannerInfo *root,
* going to be safe to do so.
*/
if (input_rel->partial_pathlist != NIL)
set_grouped_rel_consider_parallel(root, grouped_rel, target);
set_grouped_rel_consider_parallel(root, grouped_rel,
target, &agg_costs);
/*
* Determine whether it's possible to perform sort-based implementations