HxpSerein commented on code in PR #15022: URL: https://github.com/apache/iotdb/pull/15022#discussion_r1985010966
########## iotdb-core/confignode/src/main/java/org/apache/iotdb/confignode/manager/load/balancer/region/PartiteGraphPlacementDestNodeSelector.java: ########## @@ -0,0 +1,166 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF 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 + * "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.apache.iotdb.confignode.manager.load.balancer.region; + +import org.apache.iotdb.common.rpc.thrift.TConsensusGroupId; +import org.apache.iotdb.common.rpc.thrift.TDataNodeConfiguration; +import org.apache.iotdb.common.rpc.thrift.TDataNodeLocation; +import org.apache.iotdb.common.rpc.thrift.TRegionReplicaSet; +import org.apache.iotdb.confignode.manager.load.balancer.region.GreedyRegionGroupAllocator.DataNodeEntry; + +import org.apache.tsfile.utils.Pair; + +import java.util.ArrayList; +import java.util.Arrays; +import java.util.Collections; +import java.util.List; +import java.util.Map; +import java.util.Set; +import java.util.TreeMap; +import java.util.stream.Collectors; + +public class PartiteGraphPlacementDestNodeSelector implements IDestNodeSelector { + private int replicationFactor; + + private int dataNodeNum; + // The number of allocated Regions in each DataNode + private int[] regionCounter; + // The number of edges in current cluster + private int[][] combinationCounter; + private Map<Integer, Integer> fakeToRealIdMap; + private Map<Integer, Integer> realToFakeIdMap; + + private Set<Integer> remainDataNodesFakeId; + + // Pair<combinationSum, RegionSum> + Pair<Integer, Integer> bestValue; + + private Integer targetDataNode = -1; + + @Override + public TDataNodeConfiguration selectDestDataNode( + Map<Integer, TDataNodeConfiguration> availableDataNodeMap, + Map<Integer, Double> freeDiskSpaceMap, + List<TRegionReplicaSet> allocatedRegionGroups, + List<TRegionReplicaSet> databaseAllocatedRegionGroups, + int replicationFactor, + TConsensusGroupId consensusGroupId, + TRegionReplicaSet remainReplicaSet) { + prepare(replicationFactor, availableDataNodeMap, allocatedRegionGroups, remainReplicaSet); + + searchTargetDataNode(freeDiskSpaceMap); + + return availableDataNodeMap.get(fakeToRealIdMap.get(targetDataNode)); + } + + private void prepare( + int replicationFactor, + Map<Integer, TDataNodeConfiguration> availableDataNodeMap, + List<TRegionReplicaSet> allocatedRegionGroups, + TRegionReplicaSet remainReplicaSet) { + this.replicationFactor = replicationFactor; + this.fakeToRealIdMap = new TreeMap<>(); + this.realToFakeIdMap = new TreeMap<>(); + this.dataNodeNum = availableDataNodeMap.size(); + List<Integer> dataNodeIdList = + availableDataNodeMap.values().stream() + .map(c -> c.getLocation().getDataNodeId()) + .collect(Collectors.toList()); + for (int i = 0; i < dataNodeNum; i++) { + fakeToRealIdMap.put(i, dataNodeIdList.get(i)); + realToFakeIdMap.put(dataNodeIdList.get(i), i); + } + + remainDataNodesFakeId = + remainReplicaSet.dataNodeLocations.stream() + .map(TDataNodeLocation::getDataNodeId) + .map(realToFakeIdMap::get) + .collect(Collectors.toSet()); + + // Compute regionCounter and combinationCounter + this.regionCounter = new int[dataNodeNum]; + Arrays.fill(regionCounter, 0); + this.combinationCounter = new int[dataNodeNum][dataNodeNum]; + for (int i = 0; i < dataNodeNum; i++) { + Arrays.fill(combinationCounter[i], 0); + } + for (TRegionReplicaSet regionReplicaSet : allocatedRegionGroups) { + List<TDataNodeLocation> dataNodeLocations = regionReplicaSet.getDataNodeLocations(); + for (int i = 0; i < dataNodeLocations.size(); i++) { + int fakeIId = realToFakeIdMap.get(dataNodeLocations.get(i).getDataNodeId()); + regionCounter[fakeIId]++; + for (int j = i + 1; j < dataNodeLocations.size(); j++) { + int fakeJId = realToFakeIdMap.get(dataNodeLocations.get(j).getDataNodeId()); + combinationCounter[fakeIId][fakeJId] = 1; + combinationCounter[fakeJId][fakeIId] = 1; + } + } + } + + this.bestValue = new Pair<>(Integer.MAX_VALUE, Integer.MAX_VALUE); + } + + private void searchTargetDataNode(Map<Integer, Double> freeDiskSpaceMap) { + List<DataNodeEntry> entryList = new ArrayList<>(); + + for (int i = 0; i < dataNodeNum; i++) { + if (remainDataNodesFakeId.contains(i)) { + continue; + } + entryList.add( + new DataNodeEntry(i, regionCounter[i], freeDiskSpaceMap.get(fakeToRealIdMap.get(i)))); + } + Collections.sort(entryList); + + int[] alternativeReplica = new int[replicationFactor]; + + int pos = 0; + for (Integer integer : remainDataNodesFakeId) { + alternativeReplica[pos] = integer; Review Comment: If you want to support future scenarios where the number of replicas can dynamically change, it is best to systematically refactor the entire system. -- This is an automated message from the Apache Git Service. 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