rdblue commented on code in PR #5669: URL: https://github.com/apache/iceberg/pull/5669#discussion_r990825764
########## core/src/main/java/org/apache/iceberg/IncrementalFileCleanup.java: ########## @@ -0,0 +1,334 @@ +/* + * 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; + +import java.io.IOException; +import java.util.List; +import java.util.Set; +import java.util.concurrent.ConcurrentHashMap; +import java.util.concurrent.ExecutorService; +import java.util.function.Consumer; +import org.apache.iceberg.exceptions.RuntimeIOException; +import org.apache.iceberg.io.CloseableIterable; +import org.apache.iceberg.io.FileIO; +import org.apache.iceberg.relocated.com.google.common.base.Joiner; +import org.apache.iceberg.relocated.com.google.common.collect.Iterables; +import org.apache.iceberg.relocated.com.google.common.collect.Sets; +import org.apache.iceberg.util.PropertyUtil; +import org.apache.iceberg.util.SnapshotUtil; +import org.apache.iceberg.util.Tasks; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +class IncrementalFileCleanup extends FileCleanupStrategy { + private static final Logger LOG = LoggerFactory.getLogger(IncrementalFileCleanup.class); + + IncrementalFileCleanup( + FileIO fileIO, + ExecutorService deleteExecutorService, + ExecutorService planExecutorService, + Consumer<String> deleteFunc) { + super(fileIO, deleteExecutorService, planExecutorService, deleteFunc); + } + + @Override + @SuppressWarnings({"checkstyle:CyclomaticComplexity", "MethodLength"}) + public void cleanFiles(TableMetadata beforeExpiration, TableMetadata afterExpiration) { + if (afterExpiration.refs().size() > 1) { + throw new UnsupportedOperationException( + "Cannot incrementally clean files for tables with more than 1 ref"); + } + + // clean up the expired snapshots: + // 1. Get a list of the snapshots that were removed + // 2. Delete any data files that were deleted by those snapshots and are not in the table + // 3. Delete any manifests that are no longer used by current snapshots + // 4. Delete the manifest lists + + Set<Long> validIds = Sets.newHashSet(); + for (Snapshot snapshot : afterExpiration.snapshots()) { + validIds.add(snapshot.snapshotId()); + } + + Set<Long> expiredIds = Sets.newHashSet(); + for (Snapshot snapshot : beforeExpiration.snapshots()) { + long snapshotId = snapshot.snapshotId(); + if (!validIds.contains(snapshotId)) { + // the snapshot was expired + LOG.info("Expired snapshot: {}", snapshot); + expiredIds.add(snapshotId); + } + } + + if (expiredIds.isEmpty()) { + // if no snapshots were expired, skip cleanup + return; + } + + SnapshotRef branchToCleanup = Iterables.getFirst(beforeExpiration.refs().values(), null); + if (branchToCleanup == null) { + return; + } + + Snapshot latest = beforeExpiration.snapshot(branchToCleanup.snapshotId()); + List<Snapshot> snapshots = afterExpiration.snapshots(); + + // this is the set of ancestors of the current table state. when removing snapshots, this must + // only remove files that were deleted in an ancestor of the current table state to avoid + // physically deleting files that were logically deleted in a commit that was rolled back. + Set<Long> ancestorIds = + Sets.newHashSet(SnapshotUtil.ancestorIds(latest, beforeExpiration::snapshot)); + + Set<Long> pickedAncestorSnapshotIds = Sets.newHashSet(); + for (long snapshotId : ancestorIds) { + String sourceSnapshotId = + beforeExpiration + .snapshot(snapshotId) + .summary() + .get(SnapshotSummary.SOURCE_SNAPSHOT_ID_PROP); + if (sourceSnapshotId != null) { + // protect any snapshot that was cherry-picked into the current table state + pickedAncestorSnapshotIds.add(Long.parseLong(sourceSnapshotId)); + } + } + + // find manifests to clean up that are still referenced by a valid snapshot, but written by an + // expired snapshot + Set<String> validManifests = Sets.newHashSet(); + Set<ManifestFile> manifestsToScan = Sets.newHashSet(); + + // Reads and deletes are done using Tasks.foreach(...).suppressFailureWhenFinished to complete + // as much of the delete work as possible and avoid orphaned data or manifest files. + Tasks.foreach(snapshots) + .retry(3) + .suppressFailureWhenFinished() + .onFailure( + (snapshot, exc) -> + LOG.warn( + "Failed on snapshot {} while reading manifest list: {}", + snapshot.snapshotId(), + snapshot.manifestListLocation(), + exc)) + .run( + snapshot -> { + try (CloseableIterable<ManifestFile> manifests = readManifestFiles(snapshot)) { + for (ManifestFile manifest : manifests) { + validManifests.add(manifest.path()); + + long snapshotId = manifest.snapshotId(); + // whether the manifest was created by a valid snapshot (true) or an expired + // snapshot (false) + boolean fromValidSnapshots = validIds.contains(snapshotId); + // whether the snapshot that created the manifest was an ancestor of the table + // state + boolean isFromAncestor = ancestorIds.contains(snapshotId); + // whether the changes in this snapshot have been picked into the current table + // state + boolean isPicked = pickedAncestorSnapshotIds.contains(snapshotId); + // if the snapshot that wrote this manifest is no longer valid (has expired), + // then delete its deleted files. note that this is only for expired snapshots + // that are in the + // current table state + if (!fromValidSnapshots + && (isFromAncestor || isPicked) + && manifest.hasDeletedFiles()) { + manifestsToScan.add(manifest.copy()); + } + } + + } catch (IOException e) { + throw new RuntimeIOException( + e, "Failed to close manifest list: %s", snapshot.manifestListLocation()); + } + }); + + // find manifests to clean up that were only referenced by snapshots that have expired + Set<String> manifestListsToDelete = Sets.newHashSet(); + Set<String> manifestsToDelete = Sets.newHashSet(); + Set<ManifestFile> manifestsToRevert = Sets.newHashSet(); + Tasks.foreach(beforeExpiration.snapshots()) + .retry(3) + .suppressFailureWhenFinished() + .onFailure( + (snapshot, exc) -> + LOG.warn( + "Failed on snapshot {} while reading manifest list: {}", + snapshot.snapshotId(), + snapshot.manifestListLocation(), + exc)) + .run( + snapshot -> { + long snapshotId = snapshot.snapshotId(); + if (!validIds.contains(snapshotId)) { + // determine whether the changes in this snapshot are in the current table state + if (pickedAncestorSnapshotIds.contains(snapshotId)) { + // this snapshot was cherry-picked into the current table state, so skip cleaning + // it up. + // its changes will expire when the picked snapshot expires. + // A -- C -- D (source=B) + // `- B <-- this commit + return; + } + + long sourceSnapshotId = + PropertyUtil.propertyAsLong( + snapshot.summary(), SnapshotSummary.SOURCE_SNAPSHOT_ID_PROP, -1); + if (ancestorIds.contains(sourceSnapshotId)) { + // this commit was cherry-picked from a commit that is in the current table state. + // do not clean up its changes because it would revert data file additions that + // are in the current + // table. + // A -- B -- C + // `- D (source=B) <-- this commit + return; + } + + if (pickedAncestorSnapshotIds.contains(sourceSnapshotId)) { + // this commit was cherry-picked from a commit that is in the current table state. + // do not clean up its changes because it would revert data file additions that + // are in the current + // table. + // A -- C -- E (source=B) + // `- B `- D (source=B) <-- this commit + return; + } + + // find any manifests that are no longer needed + try (CloseableIterable<ManifestFile> manifests = readManifestFiles(snapshot)) { + for (ManifestFile manifest : manifests) { + if (!validManifests.contains(manifest.path())) { + manifestsToDelete.add(manifest.path()); + + boolean isFromAncestor = ancestorIds.contains(manifest.snapshotId()); + boolean isFromExpiringSnapshot = expiredIds.contains(manifest.snapshotId()); + + if (isFromAncestor && manifest.hasDeletedFiles()) { + // Only delete data files that were deleted in by an expired snapshot if + // that napshot is an ancestor of the current table state. Otherwise, a + // snapshot + // that deleted files and was rolled back will delete files that could be in + // the current + // table state. + manifestsToScan.add(manifest.copy()); + } + + if (!isFromAncestor && isFromExpiringSnapshot && manifest.hasAddedFiles()) { + // Because the manifest was written by a snapshot that is not an ancestor of + // the current table state, the files added in this manifest can be removed. + // The + // extra check whether the manifest was written by a known snapshot that was + // expired in this commit ensures that the full ancestor list between when + // the snapshot + // was written and this expiration is known and there is no missing history. + // If + // history were missing, then the snapshot could be an ancestor of the table + // state + // but the ancestor ID set would not contain it and this would be unsafe. + manifestsToRevert.add(manifest.copy()); + } + } + } + } catch (IOException e) { + throw new RuntimeIOException( + e, "Failed to close manifest list: %s", snapshot.manifestListLocation()); + } + + // add the manifest list to the delete set, if present + if (snapshot.manifestListLocation() != null) { + manifestListsToDelete.add(snapshot.manifestListLocation()); + } + } + }); + + deleteDataFiles(manifestsToScan, manifestsToRevert, validIds, afterExpiration); + LOG.warn("Manifests to delete: {}", Joiner.on(", ").join(manifestsToDelete)); + LOG.warn("Manifests Lists to delete: {}", Joiner.on(", ").join(manifestListsToDelete)); + deleteFiles(manifestsToDelete, "manifest"); + deleteFiles(manifestListsToDelete, "manifest list"); + } + + private void deleteDataFiles( Review Comment: Does this still need to be a separate function? -- This is an automated message from the Apache Git Service. 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