zhuzhurk commented on a change in pull request #16688: URL: https://github.com/apache/flink/pull/16688#discussion_r686117914
########## File path: flink-runtime/src/main/java/org/apache/flink/runtime/executiongraph/failover/flip1/SchedulingPipelinedRegionComputeUtil.java ########## @@ -0,0 +1,162 @@ +/* + * 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.flink.runtime.executiongraph.failover.flip1; + +import org.apache.flink.runtime.jobgraph.IntermediateResultPartitionID; +import org.apache.flink.runtime.scheduler.strategy.ConsumedPartitionGroup; +import org.apache.flink.runtime.scheduler.strategy.ConsumerVertexGroup; +import org.apache.flink.runtime.scheduler.strategy.ExecutionVertexID; +import org.apache.flink.runtime.scheduler.strategy.SchedulingExecutionVertex; +import org.apache.flink.runtime.scheduler.strategy.SchedulingPipelinedRegion; +import org.apache.flink.runtime.scheduler.strategy.SchedulingResultPartition; + +import java.util.ArrayList; +import java.util.Collections; +import java.util.HashSet; +import java.util.IdentityHashMap; +import java.util.List; +import java.util.Map; +import java.util.Set; +import java.util.function.Function; + +import static org.apache.flink.runtime.executiongraph.failover.flip1.PipelinedRegionComputeUtil.buildRawRegions; +import static org.apache.flink.runtime.executiongraph.failover.flip1.PipelinedRegionComputeUtil.mergeRegions; +import static org.apache.flink.runtime.executiongraph.failover.flip1.PipelinedRegionComputeUtil.uniqueRegions; +import static org.apache.flink.util.Preconditions.checkState; + +/** Utils for computing {@link SchedulingPipelinedRegion}s. */ +public final class SchedulingPipelinedRegionComputeUtil { + + public static Set<Set<SchedulingExecutionVertex>> computePipelinedRegions( + final Iterable<? extends SchedulingExecutionVertex> topologicallySortedVertices, + final Function<ExecutionVertexID, ? extends SchedulingExecutionVertex> + executionVertexRetriever, + final Function<IntermediateResultPartitionID, ? extends SchedulingResultPartition> + resultPartitionRetriever) { + + final Map<SchedulingExecutionVertex, Set<SchedulingExecutionVertex>> vertexToRegion = + buildRawRegions( + topologicallySortedVertices, + vertex -> + getNonReconnectableConsumedResults( + vertex, resultPartitionRetriever)); + + return mergeRegionsOnCycles(vertexToRegion, executionVertexRetriever); + } + + /** + * Merge the regions base on <a + * href="https://en.wikipedia.org/wiki/Tarjan%27s_strongly_connected_components_algorithm";> + * Tarjan's strongly connected components algorithm</a>. For more details please see <a + * href="https://issues.apache.org/jira/browse/FLINK-17330";>FLINK-17330</a>. + */ + private static Set<Set<SchedulingExecutionVertex>> mergeRegionsOnCycles( + final Map<SchedulingExecutionVertex, Set<SchedulingExecutionVertex>> vertexToRegion, + final Function<ExecutionVertexID, ? extends SchedulingExecutionVertex> + executionVertexRetriever) { + + final List<Set<SchedulingExecutionVertex>> regionList = + new ArrayList<>(uniqueRegions(vertexToRegion)); + final List<List<Integer>> outEdges = + buildOutEdgesDesc(vertexToRegion, regionList, executionVertexRetriever); + final Set<Set<Integer>> sccs = + StronglyConnectedComponentsComputeUtils.computeStronglyConnectedComponents( + outEdges.size(), outEdges); + + final Set<Set<SchedulingExecutionVertex>> mergedRegions = + Collections.newSetFromMap(new IdentityHashMap<>()); + for (Set<Integer> scc : sccs) { + checkState(scc.size() > 0); + + Set<SchedulingExecutionVertex> mergedRegion = new HashSet<>(); + for (int regionIndex : scc) { + mergedRegion = + mergeRegions(mergedRegion, regionList.get(regionIndex), vertexToRegion); + } + mergedRegions.add(mergedRegion); + } + + return mergedRegions; + } + + private static List<List<Integer>> buildOutEdgesDesc( + final Map<SchedulingExecutionVertex, Set<SchedulingExecutionVertex>> vertexToRegion, + final List<Set<SchedulingExecutionVertex>> regionList, + final Function<ExecutionVertexID, ? extends SchedulingExecutionVertex> + executionVertexRetriever) { + + final Map<Set<SchedulingExecutionVertex>, Integer> regionIndices = new IdentityHashMap<>(); + for (int i = 0; i < regionList.size(); i++) { + regionIndices.put(regionList.get(i), i); + } + + final List<List<Integer>> outEdges = new ArrayList<>(regionList.size()); + for (Set<SchedulingExecutionVertex> currentRegion : regionList) { + final List<Integer> currentRegionOutEdges = new ArrayList<>(); + for (SchedulingExecutionVertex vertex : currentRegion) { + for (SchedulingResultPartition producedResult : vertex.getProducedResults()) { + if (!producedResult.getResultType().isReconnectable()) { + continue; + } + for (ConsumerVertexGroup consumerVertexGroup : + producedResult.getConsumerVertexGroups()) { + for (ExecutionVertexID consumerVertexId : consumerVertexGroup) { + SchedulingExecutionVertex consumerVertex = + executionVertexRetriever.apply(consumerVertexId); + // Skip the ConsumerVertexGroup if its vertices are outside current + // regions and cannot be merged + if (!vertexToRegion.containsKey(consumerVertex)) { + break; + } + if (!currentRegion.contains(consumerVertex)) { + currentRegionOutEdges.add( + regionIndices.get(vertexToRegion.get(consumerVertex))); + } + } + } + } + } + outEdges.add(currentRegionOutEdges); + } + + return outEdges; + } + + private static Iterable<SchedulingResultPartition> getNonReconnectableConsumedResults( + SchedulingExecutionVertex vertex, + Function<IntermediateResultPartitionID, ? extends SchedulingResultPartition> + resultPartitionRetriever) { + List<SchedulingResultPartition> nonReconnectableConsumedResults = + new ArrayList<>(vertex.getConsumedPartitionGroups().size()); Review comment: Because one group can contribute 0 or multiple partitions to the result. -- This is an automated message from the Apache Git Service. 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