/*
* Copyright (c) 2017 Strapdata (http://www.strapdata.com)
* Contains some code from Elasticsearch (http://www.elastic.co)
*
* Licensed 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 "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.elassandra.cluster.routing;
import java.util.BitSet;
import java.util.Collections;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Random;
import java.util.UUID;
import org.elasticsearch.cluster.ClusterState;
import org.elasticsearch.cluster.node.DiscoveryNode;
import org.elasticsearch.cluster.routing.ShardRoutingState;
import org.elasticsearch.common.Nullable;
import org.elasticsearch.common.transport.TransportAddress;
import com.google.common.collect.Lists;
/**
* For each newRoute(), returns all local ranges and randomly pickup ranges from available nodes (may be unbalanced).
*
* @author vroyer
*
*/
public class RandomSearchStrategy extends AbstractSearchStrategy {
public class RandomRouter extends Router {
Random rnd = new Random();
public RandomRouter(final String index, final String ksName, final Map<UUID, ShardRoutingState> shardStates, final ClusterState clusterState) {
super(index, ksName, shardStates, clusterState, true);
}
@Override
public Route newRoute(@Nullable String preference, TransportAddress src) {
DiscoveryNode pivotNode = localNode;
if (this.greenShards.get(pivotNode) == null && greenShards.size() > 0) {
pivotNode = greenShards.keySet().iterator().next();
}
BitSet pivotBitset = this.greenShards.get(pivotNode);
final Map<DiscoveryNode, BitSet> selectedShards = new HashMap<DiscoveryNode, BitSet>();
selectedShards.put(pivotNode, pivotBitset);
List<DiscoveryNode> randomAvailableNodes = Lists.newArrayList(greenShards.keySet());
randomAvailableNodes.remove(pivotNode);
Collections.shuffle(randomAvailableNodes, rnd);
BitSet coverBitmap = (BitSet)pivotBitset.clone();
int i = 0;
while (coverBitmap.cardinality() != tokens.size() && i < tokens.size()) {
int x = coverBitmap.nextClearBit(i);
DiscoveryNode choice = null;
for(Iterator<DiscoveryNode> it = randomAvailableNodes.iterator(); it.hasNext(); ) {
DiscoveryNode node = it.next();
if (this.greenShards.get(node).get(x)) {
// choose the first (could choose the wider token_range, or the one having the less dropped mutations)
if (choice == null)
choice = node;
it.remove();
}
}
if (choice != null) {
BitSet choiceBitset = this.greenShards.get(choice);
choiceBitset.andNot(coverBitmap);
selectedShards.put(choice, choiceBitset);
coverBitmap.or(choiceBitset);
}
i++;
}
return new Route() {
@Override
public Map<DiscoveryNode, BitSet> selectedShards() {
return selectedShards;
}
};
}
}
@Override
public Router newRouter(final String index, final String ksName, final Map<UUID, ShardRoutingState> shardStates, final ClusterState clusterState) {
return new RandomRouter(index, ksName, shardStates, clusterState);
}
}