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/*
* Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
* or more contributor license agreements. Licensed under the Elastic License
* 2.0 and the Server Side Public License, v 1; you may not use this file except
* in compliance with, at your election, the Elastic License 2.0 or the Server
* Side Public License, v 1.
*/
package org.elasticsearch.search.aggregations.metrics;
import org.apache.lucene.search.ScoreMode;
import org.elasticsearch.common.util.DoubleArray;
import org.elasticsearch.core.Releasables;
import org.elasticsearch.index.fielddata.SortedNumericDoubleValues;
import org.elasticsearch.search.DocValueFormat;
import org.elasticsearch.search.aggregations.AggregationExecutionContext;
import org.elasticsearch.search.aggregations.Aggregator;
import org.elasticsearch.search.aggregations.InternalAggregation;
import org.elasticsearch.search.aggregations.LeafBucketCollector;
import org.elasticsearch.search.aggregations.LeafBucketCollectorBase;
import org.elasticsearch.search.aggregations.support.AggregationContext;
import org.elasticsearch.search.aggregations.support.ValuesSource;
import org.elasticsearch.search.aggregations.support.ValuesSourceConfig;
import java.io.IOException;
import java.util.Map;
public class SumAggregator extends NumericMetricsAggregator.SingleValue {
private final ValuesSource.Numeric valuesSource;
private final DocValueFormat format;
private DoubleArray sums;
private DoubleArray compensations;
SumAggregator(
String name,
ValuesSourceConfig valuesSourceConfig,
AggregationContext context,
Aggregator parent,
Map metadata
) throws IOException {
super(name, context, parent, metadata);
// TODO: stop expecting nulls here
this.valuesSource = valuesSourceConfig.hasValues() ? (ValuesSource.Numeric) valuesSourceConfig.getValuesSource() : null;
this.format = valuesSourceConfig.format();
if (valuesSource != null) {
sums = bigArrays().newDoubleArray(1, true);
compensations = bigArrays().newDoubleArray(1, true);
}
}
@Override
public ScoreMode scoreMode() {
return valuesSource != null && valuesSource.needsScores() ? ScoreMode.COMPLETE : ScoreMode.COMPLETE_NO_SCORES;
}
@Override
public LeafBucketCollector getLeafCollector(AggregationExecutionContext aggCtx, final LeafBucketCollector sub) throws IOException {
if (valuesSource == null) {
return LeafBucketCollector.NO_OP_COLLECTOR;
}
final SortedNumericDoubleValues values = valuesSource.doubleValues(aggCtx.getLeafReaderContext());
final CompensatedSum kahanSummation = new CompensatedSum(0, 0);
return new LeafBucketCollectorBase(sub, values) {
@Override
public void collect(int doc, long bucket) throws IOException {
sums = bigArrays().grow(sums, bucket + 1);
compensations = bigArrays().grow(compensations, bucket + 1);
if (values.advanceExact(doc)) {
final int valuesCount = values.docValueCount();
// Compute the sum of double values with Kahan summation algorithm which is more
// accurate than naive summation.
double sum = sums.get(bucket);
double compensation = compensations.get(bucket);
kahanSummation.reset(sum, compensation);
for (int i = 0; i < valuesCount; i++) {
double value = values.nextValue();
kahanSummation.add(value);
}
compensations.set(bucket, kahanSummation.delta());
sums.set(bucket, kahanSummation.value());
}
}
};
}
@Override
public double metric(long owningBucketOrd) {
if (valuesSource == null || owningBucketOrd >= sums.size()) {
return 0.0;
}
return sums.get(owningBucketOrd);
}
@Override
public InternalAggregation buildAggregation(long bucket) {
if (valuesSource == null || bucket >= sums.size()) {
return buildEmptyAggregation();
}
return new Sum(name, sums.get(bucket), format, metadata());
}
@Override
public InternalAggregation buildEmptyAggregation() {
return new Sum(name, 0.0, format, metadata());
}
@Override
public void doClose() {
Releasables.close(sums, compensations);
}
}