rkhachatryan commented on a change in pull request #13351: URL: https://github.com/apache/flink/pull/13351#discussion_r495095577
########## File path: flink-runtime/src/main/java/org/apache/flink/runtime/checkpoint/channel/SequentialChannelStateReaderImpl.java ########## @@ -0,0 +1,263 @@ +/* + * 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.checkpoint.channel; + +import org.apache.flink.api.java.tuple.Tuple2; +import org.apache.flink.core.fs.FSDataInputStream; +import org.apache.flink.runtime.checkpoint.OperatorSubtaskState; +import org.apache.flink.runtime.checkpoint.StateObjectCollection; +import org.apache.flink.runtime.checkpoint.TaskStateSnapshot; +import org.apache.flink.runtime.io.network.api.writer.ResultPartitionWriter; +import org.apache.flink.runtime.io.network.buffer.Buffer; +import org.apache.flink.runtime.io.network.buffer.BufferBuilder; +import org.apache.flink.runtime.io.network.buffer.BufferConsumer; +import org.apache.flink.runtime.io.network.partition.consumer.InputGate; +import org.apache.flink.runtime.io.network.partition.consumer.RecoveredInputChannel; +import org.apache.flink.runtime.state.AbstractChannelStateHandle; +import org.apache.flink.runtime.state.StreamStateHandle; +import org.apache.flink.util.Preconditions; + +import java.io.IOException; +import java.util.Collection; +import java.util.HashSet; +import java.util.List; +import java.util.Map; +import java.util.Set; +import java.util.function.Consumer; +import java.util.function.Function; +import java.util.stream.Stream; + +import static java.util.Comparator.comparingLong; +import static java.util.stream.Collectors.groupingBy; +import static java.util.stream.Collectors.toList; +import static org.apache.flink.runtime.checkpoint.channel.ChannelStateByteBuffer.wrap; + +/** + * {@link SequentialChannelStateReader} implementation. + */ +public class SequentialChannelStateReaderImpl implements SequentialChannelStateReader { + + private final TaskStateSnapshot taskStateSnapshot; + private final ChannelStateSerializer serializer; + private final ChannelStateChunkReader chunkReader; + + public SequentialChannelStateReaderImpl(TaskStateSnapshot taskStateSnapshot) { + this(taskStateSnapshot, new ChannelStateSerializerImpl()); + } + + public SequentialChannelStateReaderImpl(TaskStateSnapshot taskStateSnapshot, ChannelStateSerializer serializer) { + this.taskStateSnapshot = taskStateSnapshot; + this.serializer = serializer; + this.chunkReader = new ChannelStateChunkReader(serializer); + } + + public SequentialChannelStateReaderImpl(TaskStateSnapshot taskStateSnapshot, ChannelStateSerializer serializer, ChannelStateChunkReader chunkReader) { + this.taskStateSnapshot = taskStateSnapshot; + this.serializer = serializer; + this.chunkReader = chunkReader; + } + + @Override + public boolean hasChannelStates() { + return taskStateSnapshot.getSubtaskStateMappings().stream().anyMatch(subtaskStateEntry -> + subtaskStateEntry.getValue().getInputChannelState().stream().anyMatch(h -> !h.getOffsets().isEmpty()) || + subtaskStateEntry.getValue().getResultSubpartitionState().stream().anyMatch(h -> !h.getOffsets().isEmpty())); + } + + @Override + public void readInputData(InputGate[] inputGates) throws IOException { + try (InputChannelRecoveredStateHandler stateHandler = new InputChannelRecoveredStateHandler(inputGates)) { + read(OperatorSubtaskState::getInputChannelState, stateHandler); + } + } + + @Override + public void readOutputData(ResultPartitionWriter[] writers) throws IOException { + try (ResultSubpartitionRecoveredStateHandler stateHandler = new ResultSubpartitionRecoveredStateHandler(writers)) { + read(OperatorSubtaskState::getResultSubpartitionState, stateHandler); + } + } + + private <Info, Context, Handle extends AbstractChannelStateHandle<Info>> void read( + Function<OperatorSubtaskState, StateObjectCollection<Handle>> stateHandleExtractor, + RecoveredChannelStateHandler<Info, Context> stateHandler) throws IOException { + for (Map.Entry<StreamStateHandle, List<Handle>> delegateAndHandles : groupByDelegate(streamSubtaskStates(), stateHandleExtractor).entrySet()) { + readSequentially(delegateAndHandles.getKey(), delegateAndHandles.getValue(), stateHandler); + } + } + + private <Info, Context, Handle extends AbstractChannelStateHandle<Info>> void readSequentially( + StreamStateHandle streamStateHandle, + List<Handle> channelStateHandles, + RecoveredChannelStateHandler<Info, Context> stateHandler) throws IOException { + try (FSDataInputStream is = streamStateHandle.openInputStream()) { + serializer.readHeader(is); + for (Tuple2<Long, Info> offsetAndChannelInfo : extractOffsetsSorted(channelStateHandles)) { + chunkReader.readChunk(is, offsetAndChannelInfo.f0, stateHandler, offsetAndChannelInfo.f1); + } + } + } + + private Stream<OperatorSubtaskState> streamSubtaskStates() { + return taskStateSnapshot.getSubtaskStateMappings().stream().map(Map.Entry::getValue); + } + + private static <Info, Handle extends AbstractChannelStateHandle<Info>> Map<StreamStateHandle, List<Handle>> groupByDelegate( + Stream<OperatorSubtaskState> states, + Function<OperatorSubtaskState, StateObjectCollection<Handle>> stateHandleExtractor) { + return states + .map(stateHandleExtractor).flatMap(Collection::stream) + .peek(validate()) + .collect(groupingBy(AbstractChannelStateHandle::getDelegate)); + } + + private static <Info, Handle extends AbstractChannelStateHandle<Info>> Consumer<Handle> validate() { + Set<Info> seen = new HashSet<>(); + // expect each channel to be described only once; otherwise, buffers in channel could be re-ordered + return handle -> Preconditions.checkState(seen.add(handle.getInfo()), "duplicate channel info: %s"); + } + + private static <Info, Handle extends AbstractChannelStateHandle<Info>> List<Tuple2<Long, Info>> extractOffsetsSorted(List<Handle> channelStateHandles) { + return channelStateHandles Review comment: Offsets are sorted only across single ChannelStateHandle. They are mostly sorted across all ChannelStateHandles referring to the same file (if handles are sorted in the same way as during writing). So sorting is necessary here. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org
