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Elasticsearch subproject :server
/*
* 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.bucket;
/**
* Helper functions for common Bucketing functions
*/
public final class BucketUtils {
private BucketUtils() {}
/**
* Heuristic used to determine the size of shard-side PriorityQueues when
* selecting the top N terms from a distributed index.
*
* @param finalSize
* The number of terms required in the final reduce phase.
* @return A suggested default for the size of any shard-side PriorityQueues
*/
public static int suggestShardSideQueueSize(int finalSize) {
if (finalSize < 1) {
throw new IllegalArgumentException("size must be positive, got " + finalSize);
}
// Request 50% more buckets on the shards in order to improve accuracy
// as well as a small constant that should help with small values of 'size'
final long shardSampleSize = (long) (finalSize * 1.5 + 10);
return (int) Math.min(Integer.MAX_VALUE, shardSampleSize);
}
}