AHeise commented on a change in pull request #13845: URL: https://github.com/apache/flink/pull/13845#discussion_r519226903
########## File path: flink-streaming-java/src/main/java/org/apache/flink/streaming/runtime/io/Demultiplexer.java ########## @@ -0,0 +1,402 @@ +/* + * 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.streaming.runtime.io; + +import org.apache.flink.api.common.typeutils.TypeSerializer; +import org.apache.flink.runtime.checkpoint.InflightDataRescalingDescriptor; +import org.apache.flink.runtime.checkpoint.RescaledChannelsMapping; +import org.apache.flink.runtime.checkpoint.channel.InputChannelInfo; +import org.apache.flink.runtime.io.disk.iomanager.IOManager; +import org.apache.flink.runtime.io.network.api.VirtualChannelSelector; +import org.apache.flink.runtime.io.network.api.serialization.RecordDeserializer; +import org.apache.flink.runtime.io.network.api.serialization.SpillingAdaptiveSpanningRecordDeserializer; +import org.apache.flink.runtime.io.network.buffer.Buffer; +import org.apache.flink.runtime.plugable.DeserializationDelegate; +import org.apache.flink.runtime.plugable.SerializationDelegate; +import org.apache.flink.runtime.state.KeyGroupRangeAssignment; +import org.apache.flink.streaming.api.watermark.Watermark; +import org.apache.flink.streaming.runtime.partitioner.ConfigurableStreamPartitioner; +import org.apache.flink.streaming.runtime.partitioner.StreamPartitioner; +import org.apache.flink.streaming.runtime.streamrecord.StreamElement; +import org.apache.flink.streaming.runtime.streamrecord.StreamRecord; +import org.apache.flink.streaming.runtime.streamstatus.StreamStatus; + +import org.apache.flink.shaded.guava18.com.google.common.collect.Iterables; +import org.apache.flink.shaded.guava18.com.google.common.collect.Maps; + +import javax.annotation.Nullable; + +import java.io.IOException; +import java.util.Arrays; +import java.util.Comparator; +import java.util.Map; +import java.util.function.Function; +import java.util.function.Predicate; +import java.util.stream.Collectors; +import java.util.stream.Stream; + +/** + * {@link RecordDeserializer}-like interface for recovery. To avoid additional virtual method calls on the + * non-recovery hotpath, this interface is not extending RecordDeserializer. + */ +interface Demultiplexer extends AutoCloseable { + RecordDeserializer.DeserializationResult getNextRecord(DeserializationDelegate<StreamElement> deserializationDelegate) throws IOException; + + void setNextBuffer(Buffer buffer) throws IOException; + + void select(VirtualChannelSelector event); + + @Override + void close(); +} + +class NoDataDemultiplexer implements Demultiplexer { + private final InputChannelInfo channelInfo; + + public NoDataDemultiplexer(InputChannelInfo channelInfo) { + this.channelInfo = channelInfo; + } + + @Override + public RecordDeserializer.DeserializationResult getNextRecord(DeserializationDelegate<StreamElement> deserializationDelegate) { + throw getException(); + } + + @Override + public void setNextBuffer(Buffer buffer) { + throw getException(); + } + + @Override + public void select(VirtualChannelSelector event) { + throw getException(); + } + + private IllegalStateException getException() { + return new IllegalStateException(channelInfo + " should not receive any data/events during recovery"); + } + + @Override + public void close() { + } +} + +/** + * Parameter structure to pass all relevant information to the factory methods of @{@link Demultiplexer}. + */ +class DemultiplexParameters { + final IOManager ioManager; + final InflightDataRescalingDescriptor channelMapping; + final Function<Integer, StreamPartitioner<?>> gatePartitionerRetriever; + final SerializationDelegate<StreamRecord> delegate; + final int numberOfChannels; + final int subtaskIndex; + + @SuppressWarnings("unchecked") + DemultiplexParameters( + TypeSerializer<?> inputSerializer, + IOManager ioManager, + InflightDataRescalingDescriptor channelMapping, + Function<Integer, StreamPartitioner<?>> gatePartitionerRetriever, + int numberOfChannels, + int subtaskIndex) { + delegate = new SerializationDelegate<>((TypeSerializer<StreamRecord>) inputSerializer); + this.ioManager = ioManager; + this.channelMapping = channelMapping; + this.gatePartitionerRetriever = gatePartitionerRetriever; + this.numberOfChannels = numberOfChannels; + this.subtaskIndex = subtaskIndex; + } +} + +/** + * Demultiplexes buffers on subtask-level. + * + * <p>Example: If the current task has been downscaled from 2 to 1. Then the only new subtask needs to handle data + * originating from old subtasks 0 and 1. In this case, {@link #demultiplexersForSubtasks} contains + * {@code 0->ChannelDemultiplexer0, 1->ChannelDemultiplexer1}. + * + * <p>Since this the outer demultiplexing layer, it is also responsible for summarizing watermark and stream + * statuses of the (nested) virtual channels. + */ +class SubtaskDemultiplexer implements Demultiplexer { + private final Map<Integer, ChannelDemultiplexer> demultiplexersForSubtasks; + + /** Keep track of the last emitted watermark for all (nested) virtual channels. */ + private final Map<VirtualChannelSelector, Watermark> lastWatermarks; + + /** Keep track of the last emitted stream status for all (nested) virtual channels. */ + private final Map<VirtualChannelSelector, StreamStatus> streamStatuses; + + private VirtualChannelSelector currentSelector; + + private ChannelDemultiplexer selectedSubtask; + + public SubtaskDemultiplexer(Map<Integer, ChannelDemultiplexer> demultiplexersForSubtasks, int totalChannels) { + this.demultiplexersForSubtasks = demultiplexersForSubtasks; + final Map.Entry<Integer, ChannelDemultiplexer> defaultSelection = + Iterables.get(demultiplexersForSubtasks.entrySet(), 0); + selectedSubtask = defaultSelection.getValue(); + currentSelector = new VirtualChannelSelector(defaultSelection.getKey(), + selectedSubtask.selectedChannelIndex); + + // initialize watermarks and streamStatuses for all nested virtual channels + this.lastWatermarks = Maps.newHashMapWithExpectedSize(totalChannels); + this.streamStatuses = Maps.newHashMapWithExpectedSize(totalChannels); + getChannelSelectors().forEach(selector -> { + lastWatermarks.put(selector, Watermark.UNINITIALIZED); + streamStatuses.put(selector, StreamStatus.ACTIVE); + }); + } + + public Stream<VirtualChannelSelector> getChannelSelectors() { + return demultiplexersForSubtasks.values().stream().flatMap(ChannelDemultiplexer::getChannelSelectors); + } + + public void select(VirtualChannelSelector selector) { + currentSelector = selector; + selectedSubtask = demultiplexersForSubtasks.get(selector.getSubtaskIndex()); + if (selectedSubtask == null) { + throw new IllegalStateException( + "Cannot select " + selector + "; known channels are " + getChannelSelectors().collect(Collectors.toList())); + } + selectedSubtask.select(selector); + } + + @Override + public void setNextBuffer(Buffer buffer) throws IOException { + selectedSubtask.setNextBuffer(buffer); + } + + @Override + public RecordDeserializer.DeserializationResult getNextRecord(DeserializationDelegate<StreamElement> deserializationDelegate) throws IOException { + do { + RecordDeserializer.DeserializationResult result = selectedSubtask.getNextRecord(deserializationDelegate); + + // special handling of watermarks and stream status + if (result.isFullRecord()) { + final StreamElement element = deserializationDelegate.getInstance(); + if (element.isWatermark()) { + // basically, do not emit a watermark if not all virtual channel are past it + lastWatermarks.put(currentSelector, element.asWatermark()); + final Watermark minWatermark = lastWatermarks.values().stream() + .min(Comparator.comparing(Watermark::getTimestamp)) + .orElseThrow(() -> new IllegalStateException("Should always have a min watermark")); + // at least one virtual channel has no watermark, so don't emit any watermark yet + if (minWatermark.equals(Watermark.UNINITIALIZED)) { + continue; + } + deserializationDelegate.setInstance(minWatermark); + } else if (element.isStreamStatus()) { + streamStatuses.put(currentSelector, element.asStreamStatus()); + // summarize statuses across all virtual channels + // duplicate statuses are filtered in StatusWatermarkValve + if (streamStatuses.values().stream().anyMatch(s -> s.equals(StreamStatus.ACTIVE))) { + deserializationDelegate.setInstance(StreamStatus.ACTIVE); + } + } + } + + return result; + // loop is only re-executed for suppressed watermark + } while (true); + } + + public void close() { + demultiplexersForSubtasks.values().forEach(Demultiplexer::close); + } + + static Demultiplexer forChannel(InputChannelInfo info, DemultiplexParameters parameters) { + final int[] oldSubtaskIndexes = parameters.channelMapping.getOldSubtaskIndexes(parameters.subtaskIndex); + if (oldSubtaskIndexes.length == 0) { + return new NoDataDemultiplexer(info); + } + final int[] oldChannelIndexes = parameters.channelMapping.getChannelMapping(info.getGateIdx()) + .getOldChannelIndexes(info.getInputChannelIdx()); + if (oldChannelIndexes.length == 0) { + return new NoDataDemultiplexer(info); + } + int totalChannels = oldSubtaskIndexes.length * oldChannelIndexes.length; + Map<Integer, ChannelDemultiplexer> demultiplexersForSubtasks = Arrays.stream(oldSubtaskIndexes).boxed() + .collect(Collectors.toMap( + Function.identity(), + oldSubtaskIndex -> ChannelDemultiplexer.forChannel(oldSubtaskIndex, info, parameters, totalChannels) + )); + return new SubtaskDemultiplexer(demultiplexersForSubtasks, totalChannels); + } + + @Override + public String toString() { + return "SubtaskDemultiplexer{" + + "demultiplexersForSubtasks=" + demultiplexersForSubtasks + + '}'; + } +} + +/** + * Demultiplexes buffers on channel-level. + * + * <p>Example: If the upstream task has been downscaled from 2 to 1. Then, old channels 0 and 1 are both + * processed over new channel 0. So this channel demultiplexer has two {@link #recordDeserializersForChannels} associated + * with the respective old channels. + * + * <p>For all non-unique mappings of new channels to old channels (see + * {@link org.apache.flink.runtime.io.network.api.writer.SubtaskStateMapper} for more details), a filter + * verifies if the restored record should be indeed processed by this subtask or if it should be filtered out and + * be processed at a different subtask. + */ +class ChannelDemultiplexer implements Demultiplexer { + private final Map<Integer, RecordDeserializer<DeserializationDelegate<StreamElement>>> recordDeserializersForChannels; + + private static final Predicate<StreamRecord> NO_FILTER = record -> true; + + private final Map<Integer, Predicate<StreamRecord>> filters; + + private final int subtaskIndex; + + @Nullable + private RecordDeserializer<DeserializationDelegate<StreamElement>> selectedChannel; + + int selectedChannelIndex; + + ChannelDemultiplexer( + int subtaskIndex, + Map<Integer, Predicate<StreamRecord>> oldChannelsWithFilters, + DemultiplexParameters parameters, + int totalChannels) { + this.subtaskIndex = subtaskIndex; + this.filters = oldChannelsWithFilters; + recordDeserializersForChannels = Maps.newHashMapWithExpectedSize(oldChannelsWithFilters.size()); + for (final Integer oldChannel : oldChannelsWithFilters.keySet()) { + recordDeserializersForChannels.put(oldChannel, + new SpillingAdaptiveSpanningRecordDeserializer<>(parameters.ioManager.getSpillingDirectoriesPaths(), + SpillingAdaptiveSpanningRecordDeserializer.DEFAULT_THRESHOLD_FOR_SPILLING / totalChannels, + SpillingAdaptiveSpanningRecordDeserializer.DEFAULT_FILE_BUFFER_SIZE / totalChannels)); + } + + recordDeserializersForChannels.entrySet().stream().findFirst().ifPresent(firstEntry -> { + selectedChannel = firstEntry.getValue(); + selectedChannelIndex = firstEntry.getKey(); + }); + } + + public Stream<VirtualChannelSelector> getChannelSelectors() { + return recordDeserializersForChannels.keySet().stream() + .map(channelIndex -> new VirtualChannelSelector(subtaskIndex, channelIndex)); + } + + @Override + public RecordDeserializer.DeserializationResult getNextRecord(DeserializationDelegate<StreamElement> deserializationDelegate) throws IOException { + do { + final RecordDeserializer.DeserializationResult result = selectedChannel.getNextRecord(deserializationDelegate); + + if (result.isBufferConsumed()) { + selectedChannel.getCurrentBuffer().recycleBuffer(); + } + if (result.isFullRecord()) { + final StreamElement element = deserializationDelegate.getInstance(); + if (element.isRecord() && !filters.get(selectedChannelIndex).test(element.asRecord())) { + continue; + } + } + + return result; + // loop is re-executed for filtered full records. + } while (true); + } + + public void select(VirtualChannelSelector selector) { + selectedChannelIndex = selector.getChannelIndex(); + selectedChannel = recordDeserializersForChannels.get(selectedChannelIndex); + if (selectedChannel == null) { + throw new IllegalStateException( + "Cannot select " + selector + "; known channels are " + getChannelSelectors().collect(Collectors.toList())); + } + } + + @Override + public void setNextBuffer(Buffer buffer) throws IOException { + selectedChannel.setNextBuffer(buffer); + } + + public void close() { + for (RecordDeserializer<DeserializationDelegate<StreamElement>> deserializer : + recordDeserializersForChannels.values()) { + // recycle buffers and clear the deserializer. + Buffer buffer = deserializer.getCurrentBuffer(); + if (buffer != null && !buffer.isRecycled()) { + buffer.recycleBuffer(); + } + deserializer.clear(); + } + } + + static ChannelDemultiplexer forChannel( + int subtaskIndex, + InputChannelInfo channelInfo, + DemultiplexParameters parameters, + int totalChannels) { + final InflightDataRescalingDescriptor mapping = parameters.channelMapping; + final RescaledChannelsMapping rescaledChannelsMapping = + mapping.getChannelMapping(channelInfo.getGateIdx()); + final int[] oldChannels = rescaledChannelsMapping.getOldChannelIndexes(channelInfo.getInputChannelIdx()); + + final Map<Integer, Predicate<StreamRecord>> oldChannelsWithFilters = + Arrays.stream(oldChannels).boxed() + .collect(Collectors.toMap( + Function.identity(), + oldChannel -> getFilterForChannel(channelInfo, parameters, rescaledChannelsMapping, oldChannel))); + + return new ChannelDemultiplexer( + subtaskIndex, + oldChannelsWithFilters, + parameters, + totalChannels); + } + + private static Predicate<StreamRecord> getFilterForChannel( + InputChannelInfo channelInfo, + DemultiplexParameters parameters, + RescaledChannelsMapping rescaledChannelsMapping, + Integer oldChannel) { + return rescaledChannelsMapping.getNewChannelIndexes(oldChannel).length <= 1 ? + NO_FILTER : + createFilter(channelInfo, parameters); + } + + private static Predicate<StreamRecord> createFilter(InputChannelInfo channelInfo, DemultiplexParameters parameters) { + final StreamPartitioner partitioner = parameters.gatePartitionerRetriever.apply(channelInfo.getGateIdx()); + final int inputChannelIdx = channelInfo.getInputChannelIdx(); + final SerializationDelegate<StreamRecord> delegate = parameters.delegate; + partitioner.setup(parameters.numberOfChannels); + if (partitioner instanceof ConfigurableStreamPartitioner) { + ((ConfigurableStreamPartitioner) partitioner).configure(KeyGroupRangeAssignment.UPPER_BOUND_MAX_PARALLELISM); + } + return streamRecord -> { + delegate.setInstance(streamRecord); Review comment: Since it's only used for the specific call inside the same thread it should be safe. However, it's cheap enough to create for each filter and it's probably much easier to reason about, so I changed it as you suggested. ---------------------------------------------------------------- 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: [email protected]
