RussellSpitzer commented on a change in pull request #2660: URL: https://github.com/apache/iceberg/pull/2660#discussion_r647558348
########## File path: spark3/src/main/java/org/apache/iceberg/spark/source/SparkMicroBatchStream.java ########## @@ -0,0 +1,306 @@ +/* + * 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 java.util.Optional; +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.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.SparkSession; +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.execution.streaming.HDFSMetadataLog; +import org.apache.spark.sql.util.CaseInsensitiveStringMap; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; +import scala.reflect.ClassTag; + +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 static final Logger LOG = LoggerFactory.getLogger(SparkMicroBatchStream.class); + + 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 OffsetLog offsetLog; + + private StreamingOffset initialOffset = null; + + SparkMicroBatchStream(SparkSession spark, 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); + this.splitSize = Optional.ofNullable(Spark3Util.propertyAsLong(options, SparkReadOptions.SPLIT_SIZE, null)) + .orElseGet(() -> PropertyUtil.propertyAsLong(table.properties(), SPLIT_SIZE, SPLIT_SIZE_DEFAULT)); + this.splitLookback = Optional.ofNullable(Spark3Util.propertyAsInt(options, SparkReadOptions.LOOKBACK, null)) + .orElseGet(() -> PropertyUtil.propertyAsInt(table.properties(), SPLIT_LOOKBACK, SPLIT_LOOKBACK_DEFAULT)); + this.splitOpenFileCost = Optional.ofNullable( + Spark3Util.propertyAsLong(options, SparkReadOptions.FILE_OPEN_COST, null)) + .orElseGet(() -> PropertyUtil.propertyAsLong(table.properties(), SPLIT_OPEN_FILE_COST, + SPLIT_OPEN_FILE_COST_DEFAULT)); + this.offsetLog = OffsetLog.getInstance(spark, checkpointLocation); + } + + @Override + public Offset latestOffset() { + initialOffset(); + + Snapshot latestSnapshot = table.currentSnapshot(); + if (latestSnapshot == null) { + return StreamingOffset.START_OFFSET; + } + + return new StreamingOffset( + latestSnapshot.snapshotId(), + Iterables.size(latestSnapshot.addedFiles()), + latestSnapshot.snapshotId() == initialOffset.snapshotId()); + } + + @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 = getFileScanTasks(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() { + int batchSizeValueToDisableColumnarReads = 0; + return new ReaderFactory(batchSizeValueToDisableColumnarReads); + } + + @Override + public Offset initialOffset() { Review comment: This implementation is I think a bit different than the contract in Spark Datastream. It says ``` /** * Returns the initial offset for a streaming query to start reading from. Note that the * streaming data source should not assume that it will start reading from its initial offset: * if Spark is restarting an existing query, it will restart from the check-pointed offset rather * than the initial one. */ ``` Which I believe means we should never be looking at the offsetLog for this value. It should be the same whether or not we are starting from a checkpoint or not. -- 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] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
