Package org.elasticsearch.xpack.esql.optimizer.rules.physical.local

Class ReplaceSampledStatsBySampleAndStats

java.lang.Object

org.elasticsearch.xpack.esql.rule.Rule<SampledAggregateExec,PhysicalPlan>

org.elasticsearch.xpack.esql.optimizer.PhysicalOptimizerRules.OptimizerRule<SampledAggregateExec>

org.elasticsearch.xpack.esql.optimizer.rules.physical.local.ReplaceSampledStatsBySampleAndStats

public class ReplaceSampledStatsBySampleAndStats
extends PhysicalOptimizerRules.OptimizerRule<SampledAggregateExec>

If the original aggregate wrapped by the sampled aggregate cannot be pushed down to Lucene (which would execute exact and fast), sampling should be used to speed up the aggregation.

In that case, this rule replaces the sampled aggregate by a regular aggregate on top of a sample, with intermediate state corrections for sample-corrected aggregates (COUNT, SUM). The plan:

 FROM data | commands | SAMPLED_STATS[prob] aggs
 

is transformed into:

 FROM data | SAMPLE prob | commands | STATS aggs | EVAL sample_correction
 

Field Summary

Fields inherited from class org.elasticsearch.xpack.esql.rule.Rule

log

Constructor Summary

Constructors

Constructor	Description
ReplaceSampledStatsBySampleAndStats()

Method Summary

Modifier and Type	Method	Description
protected PhysicalPlan	rule(SampledAggregateExec plan)

Methods inherited from class org.elasticsearch.xpack.esql.optimizer.PhysicalOptimizerRules.OptimizerRule

apply

Methods inherited from class org.elasticsearch.xpack.esql.rule.Rule

name, toString, typeToken

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Details

ReplaceSampledStatsBySampleAndStats

public ReplaceSampledStatsBySampleAndStats()

Method Details

rule

protected PhysicalPlan rule(SampledAggregateExec plan)

Specified by:

rule in class PhysicalOptimizerRules.OptimizerRule<SampledAggregateExec>