SreeramGarlapati commented on a change in pull request #2611: URL: https://github.com/apache/iceberg/pull/2611#discussion_r641904262
########## File path: spark3/src/main/java/org/apache/iceberg/spark/source/SparkMicroBatchStream.java ########## @@ -0,0 +1,309 @@ +/* + * 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.util.List; +import java.util.Optional; +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.MicroBatches.MicroBatchBuilder; +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.OffsetSeq; +import org.apache.spark.sql.execution.streaming.OffsetSeqLog; +import org.apache.spark.sql.util.CaseInsensitiveStringMap; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; +import scala.Option; +import scala.collection.JavaConverters; + +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 int batchSize; + private final Long splitSize; + private final Integer splitLookback; + private final Long splitOpenFileCost; + private final boolean localityPreferred; + private final OffsetSeqLog offsetSeqLog; + + private StreamingOffset initialOffset = null; + private PlannedEndOffset previousEndOffset = 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.batchSize = Spark3Util.batchSize(table.properties(), options); + 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.offsetSeqLog = checkpointLocation != null ? + new OffsetSeqLog(spark, getOffsetLogLocation(checkpointLocation)) : + null; + } + + @Override + public Offset latestOffset() { + initialOffset(); + + if (isTableEmpty()) { + return StreamingOffset.START_OFFSET; + } + + StreamingOffset microBatchStartOffset = isFirstBatch() ? initialOffset : previousEndOffset; + if (isEndOfSnapshot(microBatchStartOffset)) { + microBatchStartOffset = getNextAvailableSnapshot(microBatchStartOffset); + } + + previousEndOffset = calculateEndOffset(microBatchStartOffset); + return previousEndOffset; + } + + @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 PlannedEndOffset, + "The end offset passed to planInputPartitions() is not the one that is returned by lastOffset()"); + PlannedEndOffset endOffset = (PlannedEndOffset) end; + + List<FileScanTask> fileScanTasks = endOffset.getMicroBatch().tasks(); + + 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() { + if (isInitialOffsetResolved()) { + return initialOffset; + } + + if (isStreamResumedFromCheckpoint()) { + initialOffset = calculateInitialOffsetFromCheckpoint(); + return initialOffset; + } + + List<Long> snapshotIds = SnapshotUtil.currentAncestors(table); + if (snapshotIds.isEmpty()) { + initialOffset = StreamingOffset.START_OFFSET; + Preconditions.checkState(isTableEmpty(), + "criteria behind isTableEmpty() changed."); + } else { + initialOffset = new StreamingOffset(Iterables.getLast(snapshotIds), 0, true); + } + + return initialOffset; + } + + @Override + public Offset deserializeOffset(String json) { + return StreamingOffset.fromJson(json); + } + + @Override + public void commit(Offset end) { + } + + @Override + public void stop() { + } + + private String getOffsetLogLocation(String checkpointLocation) { Review comment: @aokolnychyi @RussellSpitzer @rdblue @holdenk - do you folks know of a better way to read the last checkpointed offset. Am needing this **hack** for cases where spark cluster goes down and has to restart stream from an old checkpoint. I definitely DO NOT plan to Keep this HACK. Am trying to understand a better way to do this. Truly appreciate any help here. [Started a conversation in iceberg slack channel](https://the-asf.slack.com/archives/CF01LKV9S/p1622529032058200). -- 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]
