rdblue commented on a change in pull request #2660: URL: https://github.com/apache/iceberg/pull/2660#discussion_r651361370
########## File path: spark3/src/main/java/org/apache/iceberg/spark/source/SparkMicroBatchStream.java ########## @@ -0,0 +1,310 @@ +/* + * 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.iceberg.spark.source; + +import java.io.BufferedWriter; +import java.io.IOException; +import java.io.InputStream; +import java.io.OutputStream; +import java.io.OutputStreamWriter; +import java.nio.charset.StandardCharsets; +import java.util.ArrayList; +import java.util.List; +import org.apache.hadoop.fs.Path; +import org.apache.iceberg.CombinedScanTask; +import org.apache.iceberg.DataOperations; +import org.apache.iceberg.FileScanTask; +import org.apache.iceberg.MicroBatches; +import org.apache.iceberg.MicroBatches.MicroBatch; +import org.apache.iceberg.Schema; +import org.apache.iceberg.SchemaParser; +import org.apache.iceberg.SerializableTable; +import org.apache.iceberg.Snapshot; +import org.apache.iceberg.Table; +import org.apache.iceberg.io.CloseableIterable; +import org.apache.iceberg.io.FileIO; +import org.apache.iceberg.io.InputFile; +import org.apache.iceberg.io.OutputFile; +import org.apache.iceberg.relocated.com.google.common.base.Preconditions; +import org.apache.iceberg.relocated.com.google.common.collect.Iterables; +import org.apache.iceberg.relocated.com.google.common.collect.Lists; +import org.apache.iceberg.spark.Spark3Util; +import org.apache.iceberg.spark.SparkReadOptions; +import org.apache.iceberg.spark.source.SparkBatchScan.ReadTask; +import org.apache.iceberg.spark.source.SparkBatchScan.ReaderFactory; +import org.apache.iceberg.util.PropertyUtil; +import org.apache.iceberg.util.SnapshotUtil; +import org.apache.iceberg.util.TableScanUtil; +import org.apache.spark.api.java.JavaSparkContext; +import org.apache.spark.broadcast.Broadcast; +import org.apache.spark.sql.connector.read.InputPartition; +import org.apache.spark.sql.connector.read.PartitionReaderFactory; +import org.apache.spark.sql.connector.read.streaming.MicroBatchStream; +import org.apache.spark.sql.connector.read.streaming.Offset; +import org.apache.spark.sql.util.CaseInsensitiveStringMap; + +import static org.apache.iceberg.TableProperties.SPLIT_LOOKBACK; +import static org.apache.iceberg.TableProperties.SPLIT_LOOKBACK_DEFAULT; +import static org.apache.iceberg.TableProperties.SPLIT_OPEN_FILE_COST; +import static org.apache.iceberg.TableProperties.SPLIT_OPEN_FILE_COST_DEFAULT; +import static org.apache.iceberg.TableProperties.SPLIT_SIZE; +import static org.apache.iceberg.TableProperties.SPLIT_SIZE_DEFAULT; + +public class SparkMicroBatchStream implements MicroBatchStream { + private final JavaSparkContext sparkContext; + private final Table table; + private final boolean caseSensitive; + private final Schema expectedSchema; + private final Long splitSize; + private final Integer splitLookback; + private final Long splitOpenFileCost; + private final boolean localityPreferred; + private final StreamingOffset initialOffset; + + SparkMicroBatchStream(JavaSparkContext sparkContext, + Table table, boolean caseSensitive, Schema expectedSchema, + CaseInsensitiveStringMap options, String checkpointLocation) { + this.sparkContext = sparkContext; + this.table = table; + this.caseSensitive = caseSensitive; + this.expectedSchema = expectedSchema; + this.localityPreferred = Spark3Util.isLocalityEnabled(table.io(), table.location(), options); + + long tableSplitSize = PropertyUtil.propertyAsLong(table.properties(), SPLIT_SIZE, SPLIT_SIZE_DEFAULT); + this.splitSize = Spark3Util.propertyAsLong(options, SparkReadOptions.SPLIT_SIZE, tableSplitSize); + + int tableSplitLookback = PropertyUtil.propertyAsInt(table.properties(), SPLIT_LOOKBACK, SPLIT_LOOKBACK_DEFAULT); + this.splitLookback = Spark3Util.propertyAsInt(options, SparkReadOptions.LOOKBACK, tableSplitLookback); + + long tableSplitOpenFileCost = PropertyUtil.propertyAsLong( + table.properties(), SPLIT_OPEN_FILE_COST, SPLIT_OPEN_FILE_COST_DEFAULT); + this.splitOpenFileCost = Spark3Util.propertyAsLong(options, SPLIT_OPEN_FILE_COST, tableSplitOpenFileCost); + + InitialOffsetStore initialOffsetStore = InitialOffsetStore.getInstance(table, checkpointLocation); + this.initialOffset = getOrWriteInitialOffset(initialOffsetStore); + } + + @Override + public Offset latestOffset() { + table.refresh(); + Snapshot latestSnapshot = table.currentSnapshot(); + if (latestSnapshot == null) { + return StreamingOffset.START_OFFSET; + } + + // a readStream on an Iceberg table can be started from 2 types of snapshots + // 1. a valid starting Snapshot: + // when this valid starting Snapshot is the initialOffset - then, scanAllFiles must be set to true; + // for all StreamingOffsets following this - scanAllFiles must be set to false + // 2. START_OFFSET: + // if the stream started on the table from START_OFFSET - it implies - that all the subsequent Snapshots added + // will have all files as net New manifests & hence scanAllFiles can be false. + boolean scanAllFiles = !StreamingOffset.START_OFFSET.equals(initialOffset) && + latestSnapshot.snapshotId() == initialOffset.snapshotId(); + + long filesNewlyAddedInLatestSnapshot = Iterables.size(latestSnapshot.addedFiles()); + long existingFilesInheritedByLatestSnapshot = SnapshotUtil.existingDataFiles(latestSnapshot); + long positionValue = scanAllFiles ? existingFilesInheritedByLatestSnapshot + filesNewlyAddedInLatestSnapshot : + filesNewlyAddedInLatestSnapshot; + + return new StreamingOffset(latestSnapshot.snapshotId(), positionValue, scanAllFiles); + } + + @Override + public InputPartition[] planInputPartitions(Offset start, Offset end) { + if (end.equals(StreamingOffset.START_OFFSET)) { + return new InputPartition[0]; + } + + // broadcast the table metadata as input partitions will be sent to executors + Broadcast<Table> tableBroadcast = sparkContext.broadcast(SerializableTable.copyOf(table)); + String expectedSchemaString = SchemaParser.toJson(expectedSchema); + + Preconditions.checkState( + end instanceof StreamingOffset, + "The end offset passed to planInputPartitions() is not an instance of StreamingOffset."); + + Preconditions.checkState( + start instanceof StreamingOffset, + "The start offset passed to planInputPartitions() is not an instance of StreamingOffset."); + + StreamingOffset endOffset = (StreamingOffset) end; + StreamingOffset startOffset = (StreamingOffset) start; + + List<FileScanTask> fileScanTasks = calculateFileScanTasks(startOffset, endOffset); + + CloseableIterable<FileScanTask> splitTasks = TableScanUtil.splitFiles( + CloseableIterable.withNoopClose(fileScanTasks), + splitSize); + List<CombinedScanTask> combinedScanTasks = Lists.newArrayList( + TableScanUtil.planTasks(splitTasks, splitSize, splitLookback, splitOpenFileCost)); + InputPartition[] readTasks = new InputPartition[combinedScanTasks.size()]; + + for (int i = 0; i < combinedScanTasks.size(); i++) { + readTasks[i] = new ReadTask( + combinedScanTasks.get(i), tableBroadcast, expectedSchemaString, + caseSensitive, localityPreferred); + } + + return readTasks; + } + + @Override + public PartitionReaderFactory createReaderFactory() { + return new ReaderFactory(0); + } + + @Override + public Offset initialOffset() { + return initialOffset; + } + + @Override + public Offset deserializeOffset(String json) { + return StreamingOffset.fromJson(json); + } + + @Override + public void commit(Offset end) { + } + + @Override + public void stop() { + } + + private static StreamingOffset getOrWriteInitialOffset(InitialOffsetStore initialOffsetStore) { + if (initialOffsetStore.isOffsetStoreInitialized()) { + return initialOffsetStore.getInitialOffset(); + } + + return initialOffsetStore.addInitialOffset(); + } + + private List<FileScanTask> calculateFileScanTasks(StreamingOffset startOffset, StreamingOffset endOffset) { + List<FileScanTask> fileScanTasks = new ArrayList<>(); + MicroBatch latestMicroBatch = null; + StreamingOffset batchStartOffset = StreamingOffset.START_OFFSET.equals(startOffset) ? + new StreamingOffset(SnapshotUtil.oldestSnapshot(table).snapshotId(), 0, false) : + startOffset; + + do { + final StreamingOffset currentOffset = + latestMicroBatch != null && latestMicroBatch.lastIndexOfSnapshot() ? + getNextAvailableSnapshot(latestMicroBatch.snapshotId()) : + batchStartOffset; + + latestMicroBatch = MicroBatches.from(table.snapshot(currentOffset.snapshotId()), table.io()) + .caseSensitive(caseSensitive) + .specsById(table.specs()) + .generate(currentOffset.position(), Long.MAX_VALUE, currentOffset.shouldScanAllFiles()); + + fileScanTasks.addAll(latestMicroBatch.tasks()); + } while (latestMicroBatch.snapshotId() != endOffset.snapshotId()); + + return fileScanTasks; + } + + private StreamingOffset getNextAvailableSnapshot(long snapshotId) { Review comment: There are a couple problems with this method name: * Contains `get` * Returns an offset, not a snapshot so the name is misleading * It isn't clear what the relationship between the offset and the snapshot ID is I think this should be a static method in `SnapshotUtil` instead, like `snapshotAfter(Table table, long snapshotId)`. That would return the snapshot that is after the given ID in the current state's ancestors. Then you can create the offset from that. -- 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 --------------------------------------------------------------------- To unsubscribe, e-mail: issues-unsubscr...@iceberg.apache.org For additional commands, e-mail: issues-h...@iceberg.apache.org
