org.elasticsearch.index.store.distributor.LeastUsedDistributor Maven / Gradle / Ivy
/*
* Licensed to ElasticSearch and Shay Banon under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. ElasticSearch licenses this
* file to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
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* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package org.elasticsearch.index.store.distributor;
import jsr166y.ThreadLocalRandom;
import org.apache.lucene.store.Directory;
import org.elasticsearch.common.inject.Inject;
import org.elasticsearch.index.store.DirectoryService;
import java.io.IOException;
/**
* Implements directory distributor that always return the directory is the most available space
*/
public class LeastUsedDistributor extends AbstractDistributor {
@Inject
public LeastUsedDistributor(DirectoryService directoryService) throws IOException {
super(directoryService);
}
@Override
public Directory doAny() {
Directory directory = null;
long size = Long.MIN_VALUE;
int sameSize = 0;
for (Directory delegate : delegates) {
long currentSize = getUsableSpace(delegate);
if (currentSize > size) {
size = currentSize;
directory = delegate;
sameSize = 1;
} else if (currentSize == size) {
sameSize++;
// Ensure uniform distribution between all directories with the same size
if (ThreadLocalRandom.current().nextDouble() < 1.0 / sameSize) {
directory = delegate;
}
}
}
return directory;
}
@Override
public String name() {
return "least_used";
}
}