mxm commented on code in PR #20485: URL: https://github.com/apache/flink/pull/20485#discussion_r951456255
########## flink-connectors/flink-connector-base/src/main/java/org/apache/flink/connector/base/source/reader/fetcher/PauseOrResumeSplitsTask.java: ########## @@ -0,0 +1,84 @@ +/* + * 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.connector.base.source.reader.fetcher; + +import org.apache.flink.annotation.Internal; +import org.apache.flink.api.connector.source.SourceSplit; +import org.apache.flink.connector.base.source.reader.splitreader.SplitReader; + +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import java.io.IOException; +import java.util.Collection; + +import static org.apache.flink.util.Preconditions.checkNotNull; + +/** + * Changes the paused splits of a n{@link SplitReader}. The task is used by default in {@link + * SplitFetcherManager} and assumes that a {@link SplitFetcher} has multiple splits. For {@code + * SplitFetchers} with single splits, it's instead recommended to subclass {@link + * SplitFetcherManager} and pause the whole {@code SplitFetcher}. + * + * @param <SplitT> the type of the split + */ +@Internal +class PauseOrResumeSplitsTask<SplitT extends SourceSplit> implements SplitFetcherTask { + private static final Logger LOG = LoggerFactory.getLogger(PauseOrResumeSplitsTask.class); + private final SplitReader<?, SplitT> splitReader; + private final Collection<SplitT> splitsToPause; + private final Collection<SplitT> splitsToResume; + private final boolean allowUnalignedSourceSplits; + + PauseOrResumeSplitsTask( + SplitReader<?, SplitT> splitReader, + Collection<SplitT> splitsToPause, + Collection<SplitT> splitsToResume, + boolean allowUnalignedSourceSplits) { + this.splitReader = checkNotNull(splitReader); + this.splitsToPause = checkNotNull(splitsToPause); + this.splitsToResume = checkNotNull(splitsToResume); + this.allowUnalignedSourceSplits = allowUnalignedSourceSplits; + } + + @Override + public boolean run() throws IOException { + try { + splitReader.pauseOrResumeSplits(splitsToPause, splitsToResume); + } catch (UnsupportedOperationException e) { + if (!allowUnalignedSourceSplits) { + throw new UnsupportedOperationException("", e); Review Comment: +1 for no wrapping. ########## flink-streaming-java/src/main/java/org/apache/flink/streaming/api/operators/SourceOperator.java: ########## @@ -559,14 +577,67 @@ private void createOutputForSplits(List<SplitT> newSplits) { private void updateMaxDesiredWatermark(WatermarkAlignmentEvent event) { currentMaxDesiredWatermark = event.getMaxWatermark(); + checkSplitWatermarkAlignment(); sourceMetricGroup.updateMaxDesiredWatermark(currentMaxDesiredWatermark); } - private void onWatermarkEmitted(long emittedWatermark) { - lastEmittedWatermark = emittedWatermark; + @Override + public void updateCurrentEffectiveWatermark(long watermark) { + lastEmittedWatermark = watermark; checkWatermarkAlignment(); } + @Override + public void updateCurrentSplitWatermark(String splitId, long watermark) { + splitCurrentWatermarks.put(splitId, watermark); + if (currentMaxDesiredWatermark < watermark && !currentlyPausedSplits.contains(splitId)) { + pauseOrResumeSplits(Collections.singletonList(splitId), Collections.emptyList()); + currentlyPausedSplits.add(splitId); + } + } + + /** + * Finds the splits that are beyond the current max watermark and pauses them. At the same time, + * splits that have been paused and where the global watermark caught up are resumed. + * + * <p>Note: This takes effect only if there are multiple splits, otherwise it does nothing. + */ + private void checkSplitWatermarkAlignment() { + if (numSplits <= 1) { + return; // If there is only a single split, we do not pause the split but the source. + } + Collection<String> splitsToPause = new ArrayList<>(); + Collection<String> splitsToResume = new ArrayList<>(); + splitCurrentWatermarks.forEach( + (splitId, splitWatermark) -> { + if (splitWatermark > currentMaxDesiredWatermark) { + splitsToPause.add(splitId); + } else if (currentlyPausedSplits.contains(splitId)) { + splitsToResume.add(splitId); + } + }); + splitsToPause.removeAll(currentlyPausedSplits); + if (!splitsToPause.isEmpty() || !splitsToResume.isEmpty()) { + pauseOrResumeSplits(splitsToPause, splitsToResume); + currentlyPausedSplits.addAll(splitsToPause); + splitsToResume.forEach(currentlyPausedSplits::remove); + } + } + + private void pauseOrResumeSplits( + Collection<String> splitsToPause, Collection<String> splitsToResume) { + if (!allowUnalignedSourceSplits || sourceReaderSupportsPauseOrResumeSplits) { + try { + sourceReader.pauseOrResumeSplits(splitsToPause, splitsToResume); + } catch (UnsupportedOperationException e) { + sourceReaderSupportsPauseOrResumeSplits = false; + if (!allowUnalignedSourceSplits) { + throw new UnsupportedOperationException("", e); Review Comment: +1 for no wrapping. -- This is an automated message from the Apache Git Service. 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