
org.elasticsearch.cluster.routing.IndexRouting Maven / Gradle / Ivy
/*
* 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.cluster.routing;
import org.elasticsearch.cluster.metadata.IndexMetadata;
import org.elasticsearch.core.Nullable;
import java.util.function.IntConsumer;
/**
* Generates the shard id for {@code (id, routing)} pairs.
*/
public abstract class IndexRouting {
/**
* Build the routing from {@link IndexMetadata}.
*/
public static IndexRouting fromIndexMetadata(IndexMetadata indexMetadata) {
if (indexMetadata.isRoutingPartitionedIndex()) {
return new Partitioned(
indexMetadata.getRoutingNumShards(),
indexMetadata.getRoutingFactor(),
indexMetadata.getRoutingPartitionSize()
);
}
return new Unpartitioned(indexMetadata.getRoutingNumShards(), indexMetadata.getRoutingFactor());
}
private final int routingNumShards;
private final int routingFactor;
private IndexRouting(int routingNumShards, int routingFactor) {
this.routingNumShards = routingNumShards;
this.routingFactor = routingFactor;
}
/**
* Generate the single shard id that should contain a document with the
* provided {@code id} and {@code routing}.
*/
public abstract int shardId(String id, @Nullable String routing);
/**
* Collect all of the shard ids that *may* contain documents with the
* provided {@code routing}. Indices with a {@code routing_partition}
* will collect more than one shard. Indices without a partition
* will collect the same shard id as would be returned
* by {@link #shardId}.
*/
public abstract void collectSearchShards(String routing, IntConsumer consumer);
/**
* Convert a hash generated from an {@code (id, routing}) pair into a
* shard id.
*/
protected final int hashToShardId(int hash) {
return Math.floorMod(hash, routingNumShards) / routingFactor;
}
/**
* Convert a routing value into a hash.
*/
private static int effectiveRoutingToHash(String effectiveRouting) {
return Murmur3HashFunction.hash(effectiveRouting);
}
/**
* Strategy for indices that are not partitioned.
*/
private static class Unpartitioned extends IndexRouting {
Unpartitioned(int routingNumShards, int routingFactor) {
super(routingNumShards, routingFactor);
}
@Override
public int shardId(String id, @Nullable String routing) {
return hashToShardId(effectiveRoutingToHash(routing == null ? id : routing));
}
@Override
public void collectSearchShards(String routing, IntConsumer consumer) {
consumer.accept(hashToShardId(effectiveRoutingToHash(routing)));
}
}
/**
* Strategy for partitioned indices.
*/
private static class Partitioned extends IndexRouting {
private final int routingPartitionSize;
Partitioned(int routingNumShards, int routingFactor, int routingPartitionSize) {
super(routingNumShards, routingFactor);
this.routingPartitionSize = routingPartitionSize;
}
@Override
public int shardId(String id, @Nullable String routing) {
if (routing == null) {
throw new IllegalArgumentException("A routing value is required for gets from a partitioned index");
}
int offset = Math.floorMod(effectiveRoutingToHash(id), routingPartitionSize);
return hashToShardId(effectiveRoutingToHash(routing) + offset);
}
@Override
public void collectSearchShards(String routing, IntConsumer consumer) {
int hash = effectiveRoutingToHash(routing);
for (int i = 0; i < routingPartitionSize; i++) {
consumer.accept(hashToShardId(hash + i));
}
}
}
}
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