database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-07-27 12:41:57 +03:00
Code Activity

Fix costing for parallel aggregation.

Browse Source 
The original patch kind of ignored the fact that we were doing something
different from a costing point of view, but nobody noticed.  This patch
fixes that oversight.

David Rowley
This commit is contained in:
Robert Haas
2016-04-12 16:24:55 -04:00
parent 46d73e0d65
commit deb71fa971
3 changed files with 92 additions and 25 deletions
Download Patch File Download Diff File Expand all files Collapse all files

75
src/backend/optimizer/util/clauses.c
View File

@ -61,6 +61,9 @@ typedef struct
{
PlannerInfo *root;
AggClauseCosts *costs;
bool finalizeAggs;
bool combineStates;
bool serialStates;
} count_agg_clauses_context;
typedef struct
@ -540,12 +543,16 @@ contain_agg_clause_walker(Node *node, void *context)
* are no subqueries. There mustn't be outer-aggregate references either.
*/
void
count_agg_clauses(PlannerInfo *root, Node *clause, AggClauseCosts *costs)
count_agg_clauses(PlannerInfo *root, Node *clause, AggClauseCosts *costs,
bool finalizeAggs, bool combineStates, bool serialStates)
{
count_agg_clauses_context context;
context.root = root;
context.costs = costs;
context.finalizeAggs = finalizeAggs;
context.combineStates = combineStates;
context.serialStates = serialStates;
(void) count_agg_clauses_walker(clause, &context);
}
@ -562,6 +569,9 @@ count_agg_clauses_walker(Node *node, count_agg_clauses_context *context)
Form_pg_aggregate aggform;
Oid aggtransfn;
Oid aggfinalfn;
Oid aggcombinefn;
Oid aggserialfn;
Oid aggdeserialfn;
Oid aggtranstype;
int32 aggtransspace;
QualCost argcosts;
@ -583,6 +593,9 @@ count_agg_clauses_walker(Node *node, count_agg_clauses_context *context)
aggform = (Form_pg_aggregate) GETSTRUCT(aggTuple);
aggtransfn = aggform->aggtransfn;
aggfinalfn = aggform->aggfinalfn;
aggcombinefn = aggform->aggcombinefn;
aggserialfn = aggform->aggserialfn;
aggdeserialfn = aggform->aggdeserialfn;
aggtranstype = aggform->aggtranstype;
aggtransspace = aggform->aggtransspace;
ReleaseSysCache(aggTuple);
@ -592,28 +605,58 @@ count_agg_clauses_walker(Node *node, count_agg_clauses_context *context)
if (aggref->aggorder != NIL || aggref->aggdistinct != NIL)
costs->numOrderedAggs++;
/* add component function execution costs to appropriate totals */
costs->transCost.per_tuple += get_func_cost(aggtransfn) * cpu_operator_cost;
if (OidIsValid(aggfinalfn))
costs->finalCost += get_func_cost(aggfinalfn) * cpu_operator_cost;
/*
* Add the appropriate component function execution costs to
* appropriate totals.
*/
if (context->combineStates)
{
/* charge for combining previously aggregated states */
costs->transCost.per_tuple += get_func_cost(aggcombinefn) * cpu_operator_cost;
/* also add the input expressions' cost to per-input-row costs */
cost_qual_eval_node(&argcosts, (Node *) aggref->args, context->root);
costs->transCost.startup += argcosts.startup;
costs->transCost.per_tuple += argcosts.per_tuple;
/* charge for deserialization, when appropriate */
if (context->serialStates && OidIsValid(aggdeserialfn))
costs->transCost.per_tuple += get_func_cost(aggdeserialfn) * cpu_operator_cost;
}
else
costs->transCost.per_tuple += get_func_cost(aggtransfn) * cpu_operator_cost;
if (context->finalizeAggs)
{
if (OidIsValid(aggfinalfn))
costs->finalCost += get_func_cost(aggfinalfn) * cpu_operator_cost;
}
else if (context->serialStates)
{
if (OidIsValid(aggserialfn))
costs->finalCost += get_func_cost(aggserialfn) * cpu_operator_cost;
}
/*
* Add any filter's cost to per-input-row costs.
*
* XXX Ideally we should reduce input expression costs according to
* filter selectivity, but it's not clear it's worth the trouble.
* Some costs will already have been incurred by the initial aggregate
* node, so we mustn't include these again.
*/
if (aggref->aggfilter)
if (!context->combineStates)
{
cost_qual_eval_node(&argcosts, (Node *) aggref->aggfilter,
context->root);
/* add the input expressions' cost to per-input-row costs */
cost_qual_eval_node(&argcosts, (Node *) aggref->args, context->root);
costs->transCost.startup += argcosts.startup;
costs->transCost.per_tuple += argcosts.per_tuple;
/*
* Add any filter's cost to per-input-row costs.
*
* XXX Ideally we should reduce input expression costs according
* to filter selectivity, but it's not clear it's worth the
* trouble.
*/
if (aggref->aggfilter)
{
cost_qual_eval_node(&argcosts, (Node *) aggref->aggfilter,
context->root);
costs->transCost.startup += argcosts.startup;
costs->transCost.per_tuple += argcosts.per_tuple;
}
}
/*