rkhachatryan commented on a change in pull request #13351: URL: https://github.com/apache/flink/pull/13351#discussion_r494507396
########## 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 + .stream() + .flatMap(SequentialChannelStateReaderImpl::extractOffsets) + .sorted(comparingLong(offsetAndInfo -> offsetAndInfo.f0)) + .collect(toList()); + } + + private static <Info, Handle extends AbstractChannelStateHandle<Info>> Stream<Tuple2<Long, Info>> extractOffsets(Handle handle) { + return handle.getOffsets().stream().map(offset -> Tuple2.of(offset, handle.getInfo())); + } + + @Override + public void close() throws Exception { + } + +} + +interface RecoveredChannelStateHandler<Info, Context> extends AutoCloseable { + Tuple2<ChannelStateByteBuffer, Context> getBuffer(Info info) throws IOException; + + void recover(Info info, Context context) throws IOException; +} + +class InputChannelRecoveredStateHandler implements RecoveredChannelStateHandler<InputChannelInfo, Buffer> { + private final InputGate[] inputGates; + + InputChannelRecoveredStateHandler(InputGate[] inputGates) { + this.inputGates = inputGates; + } + + @Override + public Tuple2<ChannelStateByteBuffer, Buffer> getBuffer(InputChannelInfo channelInfo) throws IOException { + RecoveredInputChannel channel = getChannel(channelInfo); + Buffer buffer; + try { + buffer = channel.getBuffer(); + return Tuple2.of(wrap(buffer), buffer); + } catch (InterruptedException e) { + throw new IOException(e); + } + } + + @Override + public void recover(InputChannelInfo channelInfo, Buffer buffer) { + if (buffer.readableBytes() > 0) { + getChannel(channelInfo).onRecoveredStateBuffer(buffer); + } else { + buffer.recycleBuffer(); + } + } + + @Override + public void close() throws IOException { + // note that we need to finish all RecoveredInputChannels, not just those with state + for (final InputGate inputGate : inputGates) { + inputGate.finishReadRecoveredState(); + } + } + + private RecoveredInputChannel getChannel(InputChannelInfo info) { + return (RecoveredInputChannel) inputGates[info.getGateIdx()].getChannel(info.getInputChannelIdx()); + } +} + +class ResultSubpartitionRecoveredStateHandler implements RecoveredChannelStateHandler<ResultSubpartitionInfo, Tuple2<BufferBuilder, BufferConsumer>> { + + private final ResultPartitionWriter[] writers; + + ResultSubpartitionRecoveredStateHandler(ResultPartitionWriter[] writers) { + this.writers = writers; + } + + @Override + public Tuple2<ChannelStateByteBuffer, Tuple2<BufferBuilder, BufferConsumer>> getBuffer(ResultSubpartitionInfo subpartitionInfo) throws IOException { + BufferBuilder bufferBuilder; + try { + bufferBuilder = getWriter(subpartitionInfo).getBufferBuilder(subpartitionInfo.getSubPartitionIdx()); + } catch (InterruptedException e) { + throw new IOException(e); + } + return Tuple2.of(wrap(bufferBuilder), Tuple2.of(bufferBuilder, bufferBuilder.createBufferConsumer())); + } + + @Override + public void recover(ResultSubpartitionInfo subpartitionInfo, Tuple2<BufferBuilder, BufferConsumer> bufferConsumer) throws IOException { + bufferConsumer.f0.finish(); + getWriter(subpartitionInfo).addBufferConsumer(bufferConsumer.f1, subpartitionInfo.getSubPartitionIdx()); + } + + private ResultPartitionWriter getWriter(ResultSubpartitionInfo info) { + return writers[info.getPartitionIdx()]; + } + + @Override + public void close() { + } +} + +class ChannelStateChunkReader { + private final ChannelStateSerializer serializer; + + ChannelStateChunkReader(ChannelStateSerializer serializer) { + this.serializer = serializer; + } + + <Info, Context, Handle extends AbstractChannelStateHandle<Info>> void readChunk( + FSDataInputStream source, + long sourceOffset, + RecoveredChannelStateHandler<Info, Context> stateHandler, + Info channelInfo) throws IOException { + if (source.getPos() != sourceOffset) { + source.seek(sourceOffset); + } + int length = serializer.readLength(source); + while (length > 0) { Review comment: length is decremented below: ```length -= serializer.readData``` ---------------------------------------------------------------- This is an automated message from the Apache Git Service. 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