becketqin commented on a change in pull request #13401: URL: https://github.com/apache/flink/pull/13401#discussion_r490741989
########## File path: flink-connectors/flink-connector-files/src/main/java/org/apache/flink/connector/file/src/impl/ContinuousFileSplitEnumerator.java ########## @@ -0,0 +1,156 @@ +/* + * 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.file.src.impl; + +import org.apache.flink.api.connector.source.SourceEvent; +import org.apache.flink.api.connector.source.SplitEnumerator; +import org.apache.flink.api.connector.source.SplitEnumeratorContext; +import org.apache.flink.connector.base.source.event.RequestSplitEvent; +import org.apache.flink.connector.file.src.FileSourceSplit; +import org.apache.flink.connector.file.src.PendingSplitsCheckpoint; +import org.apache.flink.connector.file.src.assigners.FileSplitAssigner; +import org.apache.flink.connector.file.src.enumerate.FileEnumerator; +import org.apache.flink.core.fs.Path; + +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import java.io.IOException; +import java.util.Collection; +import java.util.HashSet; +import java.util.Iterator; +import java.util.List; +import java.util.Optional; +import java.util.stream.Collectors; + +import static org.apache.flink.util.Preconditions.checkArgument; +import static org.apache.flink.util.Preconditions.checkNotNull; + +/** + * A continuously monitoring enumerator. + */ +public class ContinuousFileSplitEnumerator implements SplitEnumerator<FileSourceSplit, PendingSplitsCheckpoint> { + + private static final Logger LOG = LoggerFactory.getLogger(ContinuousFileSplitEnumerator.class); + + private final SplitEnumeratorContext<FileSourceSplit> context; + + private final FileSplitAssigner splitAssigner; + + private final FileEnumerator enumerator; + + private final HashSet<Path> pathsAlreadyProcessed; + + private final HashSet<Integer> readersAwaitingSplit; + + private final Path[] paths; + + private final long discoveryInterval; + + // ------------------------------------------------------------------------ + + public ContinuousFileSplitEnumerator( + SplitEnumeratorContext<FileSourceSplit> context, + FileEnumerator enumerator, + FileSplitAssigner splitAssigner, + Path[] paths, + Collection<Path> alreadyDiscoveredPaths, + long discoveryInterval) { + + checkArgument(discoveryInterval > 0L); + this.context = checkNotNull(context); + this.enumerator = checkNotNull(enumerator); + this.splitAssigner = checkNotNull(splitAssigner); + this.paths = paths; + this.discoveryInterval = discoveryInterval; + this.pathsAlreadyProcessed = new HashSet<>(alreadyDiscoveredPaths); + this.readersAwaitingSplit = new HashSet<>(); + } + + @Override + public void start() { + context.callAsync( + () -> enumerator.enumerateSplits(paths, 1), + this::processDiscoveredSplits, + discoveryInterval, discoveryInterval); + } + + @Override + public void close() throws IOException { + // no resources to close + } + + @Override + public void addReader(int subtaskId) { + // this source is purely lazy-pull-based, nothing to do upon registration + } + + @Override + public void handleSourceEvent(int subtaskId, SourceEvent sourceEvent) { + if (sourceEvent instanceof RequestSplitEvent) { + readersAwaitingSplit.add(subtaskId); + assignSplits(); + } + else { + LOG.error("Received unrecognized event: {}", sourceEvent); + } + } + + @Override + public void addSplitsBack(List<FileSourceSplit> splits, int subtaskId) { + LOG.debug("File Source Enumerator adds splits back: {}", splits); + splitAssigner.addSplits(splits); + } + + @Override + public PendingSplitsCheckpoint snapshotState() throws Exception { + return PendingSplitsCheckpoint.fromCollectionSnapshot(splitAssigner.remainingSplits(), pathsAlreadyProcessed); + } + + // ------------------------------------------------------------------------ + + private void processDiscoveredSplits(Collection<FileSourceSplit> splits, Throwable error) { + if (error != null) { + LOG.error("Failed to enumerate files", error); + return; + } + + final Collection<FileSourceSplit> newSplits = splits.stream() + .filter((split) -> pathsAlreadyProcessed.add(split.path())) + .collect(Collectors.toList()); + splitAssigner.addSplits(newSplits); + + assignSplits(); + } + + private void assignSplits() { + final Iterator<Integer> awaitingReader = readersAwaitingSplit.iterator(); + + while (awaitingReader.hasNext()) { + final int awaitingSubtask = awaitingReader.next(); + final Optional<FileSourceSplit> nextSplit = splitAssigner.getNext(null); Review comment: Should we pass in `hostName` instead of `null` here? ########## File path: flink-connectors/flink-connector-files/src/main/java/org/apache/flink/connector/file/src/impl/FileSourceSplitReader.java ########## @@ -0,0 +1,110 @@ +/* + * 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.file.src.impl; + +import org.apache.flink.configuration.Configuration; +import org.apache.flink.connector.base.source.reader.RecordsWithSplitIds; +import org.apache.flink.connector.base.source.reader.splitreader.SplitReader; +import org.apache.flink.connector.base.source.reader.splitreader.SplitsAddition; +import org.apache.flink.connector.base.source.reader.splitreader.SplitsChange; +import org.apache.flink.connector.file.src.FileSourceSplit; +import org.apache.flink.connector.file.src.reader.BulkFormat; +import org.apache.flink.connector.file.src.util.RecordAndPosition; + +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import javax.annotation.Nullable; + +import java.io.IOException; +import java.util.ArrayDeque; +import java.util.Queue; + +/** + * The {@link SplitReader} implementation for the file source. + */ +final class FileSourceSplitReader<T> implements SplitReader<RecordAndPosition<T>, FileSourceSplit> { + + private static final Logger LOG = LoggerFactory.getLogger(FileSourceSplitReader.class); + + private final Configuration config; + private final BulkFormat<T> readerFactory; + + private final Queue<FileSourceSplit> splits; + + @Nullable + private BulkFormat.Reader<T> currentReader; + @Nullable + private String currentSplitId; + + public FileSourceSplitReader(Configuration config, BulkFormat<T> readerFactory) { + this.config = config; + this.readerFactory = readerFactory; + this.splits = new ArrayDeque<>(); + } + + @Override + public RecordsWithSplitIds<RecordAndPosition<T>> fetch() throws IOException { + checkSplitOrStartNext(); + + final BulkFormat.RecordIterator<T> nextBatch = currentReader.readBatch(); + return nextBatch == null ? finishSplit() : FileRecords.forRecords(currentSplitId, nextBatch); + } + + @Override + public void handleSplitsChanges(final SplitsChange<FileSourceSplit> splitChange) { + if (!(splitChange instanceof SplitsAddition)) { + throw new UnsupportedOperationException(String.format( + "The SplitChange type of %s is not supported.", splitChange.getClass())); + } + + LOG.debug("Handling split change {}", splitChange); + splits.addAll(splitChange.splits()); + } + + @Override + public void wakeUp() {} + + private void checkSplitOrStartNext() throws IOException { + if (currentReader != null) { + return; + } + + final FileSourceSplit nextSplit = splits.poll(); + if (nextSplit == null) { + throw new IOException("Cannot fetch from another split - no split remaining"); + } + + currentSplitId = nextSplit.splitId(); + currentReader = nextSplit.skippedRecordCount() == 0 ? Review comment: Nit: it seems we are always using `nextSplit.skippedRecordCount()` here, so maybe just ``` currentReader = readerFactory.createReader(config, nextSplit.path(), nextSplit.offset(), nextSplit.length(), nextSplit.skippedRecordCount()); ``` ########## File path: flink-connectors/flink-connector-files/src/main/java/org/apache/flink/connector/file/src/FileSourceSplit.java ########## @@ -0,0 +1,190 @@ +/* + * 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.file.src; + +import org.apache.flink.annotation.PublicEvolving; +import org.apache.flink.api.connector.source.SourceSplit; +import org.apache.flink.core.fs.Path; + +import javax.annotation.Nullable; + +import java.io.Serializable; +import java.util.Arrays; + +import static org.apache.flink.util.Preconditions.checkArgument; +import static org.apache.flink.util.Preconditions.checkNotNull; + +/** + * A {@link SourceSplit} that represents a file, or a region of a file. + */ +@PublicEvolving +public class FileSourceSplit implements SourceSplit, Serializable { + + private static final long serialVersionUID = 1L; + + private static final String[] NO_HOSTS = new String[0]; + + /** The unique ID of the split. Unique within the scope of this source. */ + private final String id; + + /** The path of the file referenced by this split. */ + private final Path filePath; + + /** The position of the first byte in the file to process. */ + private final long offset; + + /** The number of bytes in the file to process. */ + private final long length; + + /** The number of records to be skipped from the beginning of the split. + * This is for file formats that cannot pinpoint every exact record position via an offset, + * due to read buffers or bulk encoding or compression. */ + private final long skippedRecordCount; + + /** The names of the hosts storing this range of the file. Empty, if no host information is available. */ + private final String[] hostnames; + + /** The splits are frequently serialized into checkpoints. + * Caching the byte representation makes repeated serialization cheap. + * This field is used by {@link FileSourceSplitSerializer}. */ + @Nullable + transient byte[] serializedFormCache; Review comment: Can you help me understand this `serializedFormCache` a bit more? It seems that currently it is not used because `FileSourceSplitState.toFileSourceSplit()` always passes null as the serializedForm. ########## File path: flink-connectors/flink-connector-files/src/main/java/org/apache/flink/connector/file/src/reader/FileRecordFormatAdapter.java ########## @@ -0,0 +1,143 @@ +/* + * 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.file.src.reader; + +import org.apache.flink.api.common.typeinfo.TypeInformation; +import org.apache.flink.configuration.ConfigOption; +import org.apache.flink.configuration.ConfigOptions; +import org.apache.flink.configuration.Configuration; +import org.apache.flink.connector.file.src.util.CheckpointablePosition; +import org.apache.flink.connector.file.src.util.IteratorResultIterator; +import org.apache.flink.core.fs.Path; +import org.apache.flink.util.ExceptionUtils; +import org.apache.flink.util.IOUtils; + +import javax.annotation.Nullable; + +import java.io.IOException; +import java.util.ArrayList; + +import static org.apache.flink.util.Preconditions.checkArgument; +import static org.apache.flink.util.Preconditions.checkNotNull; + +/** + * The FormatReaderAdapter turns a {@link FileRecordFormat} into a {@link BulkFormat}. + */ +public final class FileRecordFormatAdapter<T> implements BulkFormat<T> { + + /** + * Config option for the number of records to hand over in each fetch. + * + * <p>The number should be large enough so that the thread-to-thread handover overhead + * is amortized across the records, but small enough so that the these records together do + * not consume too memory to be feasible. + */ + public static final ConfigOption<Integer> RECORDS_PER_FETCH = ConfigOptions Review comment: Would it make sense to define this config in `FileRecordFormat` instead? We are not expecting this class to be exposed to the end users, right? ########## File path: flink-connectors/flink-connector-files/src/main/java/org/apache/flink/connector/file/src/impl/ContinuousFileSplitEnumerator.java ########## @@ -0,0 +1,156 @@ +/* + * 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.file.src.impl; + +import org.apache.flink.api.connector.source.SourceEvent; +import org.apache.flink.api.connector.source.SplitEnumerator; +import org.apache.flink.api.connector.source.SplitEnumeratorContext; +import org.apache.flink.connector.base.source.event.RequestSplitEvent; +import org.apache.flink.connector.file.src.FileSourceSplit; +import org.apache.flink.connector.file.src.PendingSplitsCheckpoint; +import org.apache.flink.connector.file.src.assigners.FileSplitAssigner; +import org.apache.flink.connector.file.src.enumerate.FileEnumerator; +import org.apache.flink.core.fs.Path; + +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import java.io.IOException; +import java.util.Collection; +import java.util.HashSet; +import java.util.Iterator; +import java.util.List; +import java.util.Optional; +import java.util.stream.Collectors; + +import static org.apache.flink.util.Preconditions.checkArgument; +import static org.apache.flink.util.Preconditions.checkNotNull; + +/** + * A continuously monitoring enumerator. + */ +public class ContinuousFileSplitEnumerator implements SplitEnumerator<FileSourceSplit, PendingSplitsCheckpoint> { + + private static final Logger LOG = LoggerFactory.getLogger(ContinuousFileSplitEnumerator.class); + + private final SplitEnumeratorContext<FileSourceSplit> context; + + private final FileSplitAssigner splitAssigner; + + private final FileEnumerator enumerator; + + private final HashSet<Path> pathsAlreadyProcessed; Review comment: It seems this set will ever grow? ########## File path: flink-connectors/flink-connector-files/src/main/java/org/apache/flink/connector/file/src/util/IteratorResultIterator.java ########## @@ -0,0 +1,64 @@ +/* + * 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.file.src.util; + +import org.apache.flink.connector.file.src.reader.BulkFormat; + +import javax.annotation.Nullable; + +import java.util.Iterator; + +/** + * A simple {@link BulkFormat.RecordIterator} that returns the elements of an iterator, one after the other. + * + * @param <E> The type of the record returned by the iterator. + */ +public final class IteratorResultIterator<E> implements BulkFormat.RecordIterator<E> { + + private final Iterator<E> records; + + private final MutableRecordAndPosition<E> recordAndPosition; + + public IteratorResultIterator( + final Iterator<E> records, + final long offset, + final long startingSkipCount) { + this.records = records; + this.recordAndPosition = new MutableRecordAndPosition<>(); + this.recordAndPosition.setPosition(offset, startingSkipCount); + } + + // ------------------------------------------------------------------------- + // Result Iterator Methods + // ------------------------------------------------------------------------- + + @Nullable + @Override + public RecordAndPosition<E> next() { + if (records.hasNext()) { + recordAndPosition.setNext(records.next()); + return recordAndPosition; + } else { + return null; + } + } + + @Override + public void close() {} Review comment: Any reason there is no `recycler` for this iterator? Also, I am wondering if it would be more clear to have a `RecyclableRecordIterator` to be the parent class of these iterators. ########## File path: flink-connectors/flink-connector-files/src/main/java/org/apache/flink/connector/file/src/reader/BulkFormat.java ########## @@ -0,0 +1,158 @@ +/* + * 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.file.src.reader; + +import org.apache.flink.api.common.typeinfo.TypeInformation; +import org.apache.flink.configuration.Configuration; +import org.apache.flink.connector.file.src.util.MutableRecordAndPosition; +import org.apache.flink.connector.file.src.util.RecordAndPosition; +import org.apache.flink.core.fs.Path; + +import javax.annotation.Nullable; + +import java.io.Closeable; +import java.io.IOException; +import java.io.Serializable; + +/** + * The {@code BulkFormat} reads and decodes batches of records at a time. Examples of bulk formats + * are formats like ORC or Parquet. + * + * <p>The actual reading is done by the {@link BulkFormat.Reader}, which is created in the + * {@link BulkFormat#createReader(Configuration, Path, long, long)} or + * {@link BulkFormat#createReader(Configuration, Path, long, long, long)} methods. + * The outer class acts mainly as a configuration holder and factory for the reader. + * + * <h2>Checkpointing</h2> + * + * <p>The bulk reader returns an iterator structure per batch. The iterator produces records together + * with a position. That position is the point from where the reading can be resumed AFTER + * the records was emitted. So that position points effectively to the record AFTER the current record. + * + * <p>The simplest way to return this position information is to always assume a zero offset in the file + * and simply increment the record count. Note that in this case the fist record would be returned with + * a record count of one, the second one with a record count of two, etc. + * + * <p>Formats that have the ability to efficiently seek to a record (or to every n-th record) by offset + * in the file can work with the position field to avoid having to read and discard many records on recovery. + * + * <h2>Serializable</h2> + * + * <p>Like many other API classes in Flink, the outer class is serializable to support sending instances + * to distributed workers for parallel execution. This is purely short-term serialization for RPC and + * no instance of this will be long-term persisted in a serialized form. + * + * <h2>Record Batching</h2> + * + * <p>Internally in the file source, the readers pass batches of records from the reading + * threads (that perform the typically blocking I/O operations) to the async mailbox threads that + * do the streaming and batch data processing. Passing records in batches (rather than one-at-a-time) + * much reduce the thread-to-thread handover overhead. + * + * <p>For the {@code BulkFormat}, one batch (as returned by {@link BulkFormat.Reader#readBatch()}) is + * handed over as one. + */ +public interface BulkFormat<T> extends Serializable { + + /** + * Creates a new reader that reads from {@code filePath} starting at {@code offset} and reads + * until {@code length} bytes after the offset. + */ + default BulkFormat.Reader<T> createReader(Configuration config, Path filePath, long offset, long length) throws IOException { + return createReader(config, filePath, offset, length, 0L); + } + + /** + * Creates a new reader that reads from {@code filePath} starting at {@code offset} and reads + * until {@code length} bytes after the offset. A number of {@code recordsToSkip} records should be + * read and discarded after the offset. This is typically part of restoring a reader to a checkpointed + * position. + */ + BulkFormat.Reader<T> createReader(Configuration config, Path filePath, long offset, long length, long recordsToSkip) throws IOException; + + /** + * Gets the type produced by this format. This type will be the type produced by the file + * source as a whole. + */ + TypeInformation<T> getProducedType(); Review comment: Should this class extend `ResultTypeQueryale`? ########## File path: flink-connectors/flink-connector-files/src/main/java/org/apache/flink/connector/file/src/impl/FileSourceSplitReader.java ########## @@ -0,0 +1,110 @@ +/* + * 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.file.src.impl; + +import org.apache.flink.configuration.Configuration; +import org.apache.flink.connector.base.source.reader.RecordsWithSplitIds; +import org.apache.flink.connector.base.source.reader.splitreader.SplitReader; +import org.apache.flink.connector.base.source.reader.splitreader.SplitsAddition; +import org.apache.flink.connector.base.source.reader.splitreader.SplitsChange; +import org.apache.flink.connector.file.src.FileSourceSplit; +import org.apache.flink.connector.file.src.reader.BulkFormat; +import org.apache.flink.connector.file.src.util.RecordAndPosition; + +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import javax.annotation.Nullable; + +import java.io.IOException; +import java.util.ArrayDeque; +import java.util.Queue; + +/** + * The {@link SplitReader} implementation for the file source. + */ +final class FileSourceSplitReader<T> implements SplitReader<RecordAndPosition<T>, FileSourceSplit> { + + private static final Logger LOG = LoggerFactory.getLogger(FileSourceSplitReader.class); + + private final Configuration config; + private final BulkFormat<T> readerFactory; + + private final Queue<FileSourceSplit> splits; + + @Nullable + private BulkFormat.Reader<T> currentReader; + @Nullable + private String currentSplitId; + + public FileSourceSplitReader(Configuration config, BulkFormat<T> readerFactory) { + this.config = config; + this.readerFactory = readerFactory; + this.splits = new ArrayDeque<>(); + } + + @Override + public RecordsWithSplitIds<RecordAndPosition<T>> fetch() throws IOException { + checkSplitOrStartNext(); + + final BulkFormat.RecordIterator<T> nextBatch = currentReader.readBatch(); + return nextBatch == null ? finishSplit() : FileRecords.forRecords(currentSplitId, nextBatch); + } + + @Override + public void handleSplitsChanges(final SplitsChange<FileSourceSplit> splitChange) { + if (!(splitChange instanceof SplitsAddition)) { + throw new UnsupportedOperationException(String.format( + "The SplitChange type of %s is not supported.", splitChange.getClass())); + } + + LOG.debug("Handling split change {}", splitChange); + splits.addAll(splitChange.splits()); + } + + @Override + public void wakeUp() {} Review comment: Can `BulkFormat.Reader#readBatch()` be blocking? Or are we expecting the method to be non-blocking? The Java doc says the return value should be null when it is end of split input. So what is expected to be returned when there are more records, but not available for return yet? ---------------------------------------------------------------- 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
