rdblue commented on code in PR #4329: URL: https://github.com/apache/iceberg/pull/4329#discussion_r890309483
########## flink/v1.14/flink/src/main/java/org/apache/iceberg/flink/source/enumerator/ContinuousSplitPlannerImpl.java: ########## @@ -0,0 +1,184 @@ +/* + * 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.flink.source.enumerator; + +import java.util.Collections; +import java.util.List; +import java.util.Optional; +import java.util.concurrent.ExecutorService; +import org.apache.flink.annotation.Internal; +import org.apache.flink.annotation.VisibleForTesting; +import org.apache.flink.util.Preconditions; +import org.apache.iceberg.Snapshot; +import org.apache.iceberg.Table; +import org.apache.iceberg.flink.source.FlinkSplitPlanner; +import org.apache.iceberg.flink.source.ScanContext; +import org.apache.iceberg.flink.source.StreamingStartingStrategy; +import org.apache.iceberg.flink.source.split.IcebergSourceSplit; +import org.apache.iceberg.util.SnapshotUtil; +import org.apache.iceberg.util.ThreadPools; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +@Internal +public class ContinuousSplitPlannerImpl implements ContinuousSplitPlanner { + private static final Logger LOG = LoggerFactory.getLogger(ContinuousSplitPlannerImpl.class); + + private final Table table; + private final ScanContext scanContext; + private final ExecutorService workerPool; + + public ContinuousSplitPlannerImpl(Table table, ScanContext scanContext, String threadPoolName) { + this.table = table; + this.scanContext = scanContext; + this.workerPool = ThreadPools.newWorkerPool( + "iceberg-plan-worker-pool-" + threadPoolName, scanContext.planParallelism()); + } + + @Override + public ContinuousEnumerationResult planSplits(IcebergEnumeratorPosition lastPosition) { + table.refresh(); + if (lastPosition != null) { + return discoverIncrementalSplits(lastPosition); + } else { + return discoverInitialSplits(); + } + } + + /** + * Discover incremental changes between @{code lastPosition} and current table snapshot + */ + private ContinuousEnumerationResult discoverIncrementalSplits(IcebergEnumeratorPosition lastPosition) { + Snapshot currentSnapshot = table.currentSnapshot(); + if (currentSnapshot == null) { + // empty table + Preconditions.checkArgument(lastPosition.snapshotId() == null, + "Invalid last enumerated position for an empty table: not null"); + LOG.info("Skip incremental scan because table is empty"); + return new ContinuousEnumerationResult(Collections.emptyList(), lastPosition, lastPosition); + } else { + if (lastPosition.snapshotId() != null && currentSnapshot.snapshotId() == lastPosition.snapshotId()) { + LOG.info("Current table snapshot is already enumerated: {}", currentSnapshot.snapshotId()); + return new ContinuousEnumerationResult(Collections.emptyList(), lastPosition, lastPosition); + } else { + IcebergEnumeratorPosition newPosition = IcebergEnumeratorPosition.of( + currentSnapshot.snapshotId(), currentSnapshot.timestampMillis()); + ScanContext incrementalScan = scanContext + .copyWithAppendsBetween(lastPosition.snapshotId(), currentSnapshot.snapshotId()); + List<IcebergSourceSplit> splits = FlinkSplitPlanner.planIcebergSourceSplits(table, incrementalScan, workerPool); + LOG.info("Discovered {} splits from incremental scan: " + + "from snapshot (exclusive) is {}, to snapshot (inclusive) is {}", + splits.size(), lastPosition, newPosition); + return new ContinuousEnumerationResult(splits, lastPosition, newPosition); + } + } + } + + /** + * Discovery initial set of splits based on {@link StreamingStartingStrategy}. + * + * <li>{@link ContinuousEnumerationResult#splits()} should contain initial splits + * discovered from table scan for {@link StreamingStartingStrategy#TABLE_SCAN_THEN_INCREMENTAL}. + * For all other strategies, splits collection should be empty. + * <li>{@link ContinuousEnumerationResult#toPosition()} points to the starting position + * for the next incremental split discovery with exclusive behavior. Meaning files committed + * by the snapshot from the position in {@code ContinuousEnumerationResult} won't be included + * in the next incremental scan. + */ + private ContinuousEnumerationResult discoverInitialSplits() { + Optional<Snapshot> startSnapshotOptional = startSnapshot(table, scanContext); + if (!startSnapshotOptional.isPresent()) { + return new ContinuousEnumerationResult(Collections.emptyList(), null, + IcebergEnumeratorPosition.empty()); + } + + Snapshot startSnapshot = startSnapshotOptional.get(); + LOG.info("Get starting snapshot id {} based on strategy {}", + startSnapshot.snapshotId(), scanContext.startingStrategy()); + List<IcebergSourceSplit> splits; + IcebergEnumeratorPosition toPosition; + if (scanContext.startingStrategy() == StreamingStartingStrategy.TABLE_SCAN_THEN_INCREMENTAL) { + // do a batch table scan first + splits = FlinkSplitPlanner.planIcebergSourceSplits(table, scanContext, workerPool); + LOG.info("Discovered {} splits from initial batch table scan with snapshot Id {}", + splits.size(), startSnapshot.snapshotId()); + // For TABLE_SCAN_THEN_INCREMENTAL, incremental mode starts exclusive from the startSnapshot + toPosition = IcebergEnumeratorPosition.of(startSnapshot.snapshotId(), startSnapshot.timestampMillis()); + } else { + // For all other modes, starting snapshot should be consumed inclusively. + // Use parentId to achieve the inclusive behavior. It is fine if parentId is null. + splits = Collections.emptyList(); + Long parentSnapshotId = startSnapshot.parentId(); + if (parentSnapshotId != null) { + Snapshot parentSnapshot = table.snapshot(parentSnapshotId); + Long parentSnapshotTimestampMs = parentSnapshot != null ? parentSnapshot.timestampMillis() : null; + toPosition = IcebergEnumeratorPosition.of(parentSnapshotId, parentSnapshotTimestampMs); + } else { + toPosition = IcebergEnumeratorPosition.empty(); + } + + LOG.info("Start incremental scan with start snapshot (inclusive): id = {}, timestamp = {}", + startSnapshot.snapshotId(), startSnapshot.timestampMillis()); + } + + return new ContinuousEnumerationResult(splits, null, toPosition); + } + + /** + * Calculate the starting snapshot based on the {@link StreamingStartingStrategy} defined in {@code ScanContext}. + * <p> + * If the {@link StreamingStartingStrategy} is not {@link StreamingStartingStrategy#TABLE_SCAN_THEN_INCREMENTAL}, + * the start snapshot should be consumed inclusively. + */ + @VisibleForTesting + static Optional<Snapshot> startSnapshot(Table table, ScanContext scanContext) { + switch (scanContext.startingStrategy()) { + case TABLE_SCAN_THEN_INCREMENTAL: + case INCREMENTAL_FROM_LATEST_SNAPSHOT: + return Optional.ofNullable(table.currentSnapshot()); + case INCREMENTAL_FROM_EARLIEST_SNAPSHOT: + return Optional.ofNullable(SnapshotUtil.oldestAncestor(table)); + case INCREMENTAL_FROM_SNAPSHOT_ID: + Snapshot matchedSnapshotById = table.snapshot(scanContext.startSnapshotId()); + if (matchedSnapshotById != null) { + return Optional.of(matchedSnapshotById); + } else { + throw new IllegalArgumentException( + "Start snapshot id not found in history: " + scanContext.startSnapshotId()); + } + case INCREMENTAL_FROM_SNAPSHOT_TIMESTAMP: + long snapshotIdAsOfTime = SnapshotUtil.snapshotIdAsOfTime(table, scanContext.startSnapshotTimestamp()); + Snapshot matchedSnapshotByTimestamp = table.snapshot(snapshotIdAsOfTime); + if (matchedSnapshotByTimestamp != null) { Review Comment: If we are guaranteed that the snapshot from `snapshotIdAsOfTime` is known, then we can avoid this check. -- 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. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
