org.elasticsearch.index.store.distributor.RandomWeightedDistributor Maven / Gradle / Ivy
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* http://www.apache.org/licenses/LICENSE-2.0
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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 picks a directory at random. The probability of selecting a directory
* is proportional to the amount of usable space in this directory.
*/
public class RandomWeightedDistributor extends AbstractDistributor {
@Inject
public RandomWeightedDistributor(DirectoryService directoryService) throws IOException {
super(directoryService);
}
@Override
public Directory doAny() {
long[] usableSpace = new long[delegates.length];
long size = 0;
for (int i = 0; i < delegates.length; i++) {
size += getUsableSpace(delegates[i]);
usableSpace[i] = size;
}
if (size != 0) {
long random = ThreadLocalRandom.current().nextLong(size);
for (int i = 0; i < delegates.length; i++) {
if (usableSpace[i] > random) {
return delegates[i];
}
}
}
// TODO: size is 0 - should we bail out or fall back on random distribution?
return delegates[ThreadLocalRandom.current().nextInt(delegates.length)];
}
@Override
public String name() {
return "random";
}
}