-
Notifications
You must be signed in to change notification settings - Fork 1.7k
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
[Kernel] Support cleaning expired Delta logs as part of checkpointing (…
…#3212) Add support for metadata cleanup as part of the checkpointing. Metadata cleanup removes expired Delta table log files (delta + checkpoints) according to the table log retention configuration. Any removed delta log files must not cause the table state to be inconstructible. Co-authored-by: Venki Korukanti <[email protected]>
- Loading branch information
1 parent
e1dd987
commit d467f52
Showing
10 changed files
with
612 additions
and
2 deletions.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
200 changes: 200 additions & 0 deletions
200
kernel/kernel-api/src/main/java/io/delta/kernel/internal/snapshot/MetadataCleanup.java
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,200 @@ | ||
| /* | ||
| * Copyright (2024) The Delta Lake Project Authors. | ||
| * | ||
| * Licensed 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 io.delta.kernel.internal.snapshot; | ||
|
|
||
| import static io.delta.kernel.internal.DeltaErrors.wrapEngineExceptionThrowsIO; | ||
| import static io.delta.kernel.internal.checkpoints.Checkpointer.getLatestCompleteCheckpointFromList; | ||
| import static io.delta.kernel.internal.lang.ListUtils.getFirst; | ||
| import static io.delta.kernel.internal.lang.ListUtils.getLast; | ||
| import static io.delta.kernel.internal.util.Preconditions.checkArgument; | ||
| import static java.util.stream.Collectors.toList; | ||
|
|
||
| import io.delta.kernel.engine.Engine; | ||
| import io.delta.kernel.internal.checkpoints.CheckpointInstance; | ||
| import io.delta.kernel.internal.fs.Path; | ||
| import io.delta.kernel.internal.util.Clock; | ||
| import io.delta.kernel.internal.util.FileNames; | ||
| import io.delta.kernel.utils.CloseableIterator; | ||
| import io.delta.kernel.utils.FileStatus; | ||
| import java.io.IOException; | ||
| import java.util.ArrayList; | ||
| import java.util.List; | ||
| import java.util.Optional; | ||
| import org.slf4j.Logger; | ||
| import org.slf4j.LoggerFactory; | ||
|
|
||
| public class MetadataCleanup { | ||
| private static final Logger logger = LoggerFactory.getLogger(MetadataCleanup.class); | ||
|
|
||
| private MetadataCleanup() {} | ||
|
|
||
| /** | ||
| * Delete the Delta log files (delta and checkpoint files) that are expired according to the table | ||
| * metadata retention settings. While deleting the log files, it makes sure the time travel | ||
| * continues to work for all unexpired table versions. | ||
| * | ||
| * <p>Here is algorithm: | ||
| * | ||
| * <ul> | ||
| * <li>Initial the potential delete file list: `potentialFilesToDelete` as an empty list | ||
| * <li>Initialize the last seen checkpoint file list: `lastSeenCheckpointFiles`. There could be | ||
| * one or more checkpoint files for a given version. | ||
| * <li>List the delta log files starting with prefix "00000000000000000000." (%020d). For each | ||
| * file: | ||
| * <ul> | ||
| * <li>Step 1: Check if the `lastSeenCheckpointFiles` contains a complete checkpoint, then | ||
| * <ul> | ||
| * <li>Step 1.1: delete all files in `potentialFilesToDelete`. Now we know there is | ||
| * a checkpoint that contains the compacted Delta log up to the checkpoint | ||
| * version and all commit/checkpoint files before this checkpoint version are | ||
| * not needed. | ||
| * <li>Step 1.2: add `lastCheckpointFiles` to `potentialFileStoDelete` list. This | ||
| * checkpoint is potential candidate to delete later if we find another | ||
| * checkpoint | ||
| * </ul> | ||
| * <li>Step 2: If the timestamp falls within the retention period, stop | ||
| * <li>Step 3: If the file is a delta log file, add it to the `potentialFilesToDelete` | ||
| * list | ||
| * <li>Step 4: If the file is a checkpoint file, add it to the `lastSeenCheckpointFiles` | ||
| * </ul> | ||
| * </ul> | ||
| * | ||
| * @param engine {@link Engine} instance to delete the expired log files | ||
| * @param clock {@link Clock} instance to get the current time. Useful in testing to mock the | ||
| * current time. | ||
| * @param tablePath Table location | ||
| * @param retentionMillis Log file retention period in milliseconds | ||
| * @return number of log files deleted | ||
| * @throws IOException if an error occurs while deleting the log files | ||
| */ | ||
| public static long cleanupExpiredLogs( | ||
| Engine engine, Clock clock, Path tablePath, long retentionMillis) throws IOException { | ||
| checkArgument(retentionMillis >= 0, "Retention period must be non-negative"); | ||
|
|
||
| List<String> potentialLogFilesToDelete = new ArrayList<>(); | ||
| long lastSeenCheckpointVersion = -1; // -1 indicates no checkpoint seen yet | ||
| List<String> lastSeenCheckpointFiles = new ArrayList<>(); | ||
|
|
||
| long fileCutOffTime = clock.getTimeMillis() - retentionMillis; | ||
| logger.info("{}: Starting the deletion of log files older than {}", tablePath, fileCutOffTime); | ||
| long numDeleted = 0; | ||
| try (CloseableIterator<FileStatus> files = listDeltaLogs(engine, tablePath)) { | ||
| while (files.hasNext()) { | ||
| // Step 1: Check if the `lastSeenCheckpointFiles` contains a complete checkpoint | ||
| Optional<CheckpointInstance> lastCompleteCheckpoint = | ||
| getLatestCompleteCheckpointFromList( | ||
| lastSeenCheckpointFiles.stream().map(CheckpointInstance::new).collect(toList()), | ||
| CheckpointInstance.MAX_VALUE); | ||
|
|
||
| if (lastCompleteCheckpoint.isPresent()) { | ||
| // Step 1.1: delete all files in `potentialFilesToDelete`. Now we know there is a | ||
| // checkpoint that contains the compacted Delta log up to the checkpoint version and all | ||
| // commit/checkpoint files before this checkpoint version are not needed. add | ||
| // `lastCheckpointFiles` to `potentialFileStoDelete` list. This checkpoint is potential | ||
| // candidate to delete later if we find another checkpoint | ||
| if (!potentialLogFilesToDelete.isEmpty()) { | ||
| logger.info( | ||
| "{}: Deleting log files (start = {}, end = {}) because a checkpoint at " | ||
| + "version {} indicates that these log files are no longer needed.", | ||
| tablePath, | ||
| getFirst(potentialLogFilesToDelete), | ||
| getLast(potentialLogFilesToDelete), | ||
| lastSeenCheckpointVersion); | ||
|
|
||
| numDeleted += deleteLogFiles(engine, potentialLogFilesToDelete); | ||
| potentialLogFilesToDelete.clear(); | ||
| } | ||
|
|
||
| // Step 1.2: add `lastCheckpointFiles` to `potentialFileStoDelete` list. This checkpoint | ||
| // is potential candidate to delete later if we find another checkpoint | ||
| potentialLogFilesToDelete.addAll(lastSeenCheckpointFiles); | ||
| lastSeenCheckpointFiles.clear(); | ||
| lastSeenCheckpointVersion = -1; | ||
| } | ||
|
|
||
| FileStatus nextFile = files.next(); | ||
|
|
||
| // Step 2: If the timestamp is earlier than the retention period, stop | ||
| if (nextFile.getModificationTime() > fileCutOffTime) { | ||
| if (!potentialLogFilesToDelete.isEmpty()) { | ||
| logger.info( | ||
| "{}: Skipping deletion of expired log files {}, because there is no checkpoint " | ||
| + "file that indicates that the log files are no longer needed. ", | ||
| tablePath, | ||
| potentialLogFilesToDelete.size()); | ||
| } | ||
| break; | ||
| } | ||
|
|
||
| if (FileNames.isCommitFile(nextFile.getPath())) { | ||
| // Step 3: If the file is a delta log file, add it to the `potentialFilesToDelete` list | ||
| // We can't delete these files until we encounter a checkpoint later that indicates | ||
| // that the log files are no longer needed. | ||
| potentialLogFilesToDelete.add(nextFile.getPath()); | ||
| } else if (FileNames.isCheckpointFile(nextFile.getPath())) { | ||
| // Step 4: If the file is a checkpoint file, add it to the `lastSeenCheckpointFiles` | ||
| long newLastSeenCheckpointVersion = FileNames.checkpointVersion(nextFile.getPath()); | ||
| checkArgument( | ||
| lastSeenCheckpointVersion == -1 | ||
| || newLastSeenCheckpointVersion >= lastSeenCheckpointVersion); | ||
|
|
||
| if (lastSeenCheckpointVersion != -1 | ||
| && newLastSeenCheckpointVersion > lastSeenCheckpointVersion) { | ||
| // We have found checkpoint file for a new version. This means the files gathered for | ||
| // the last checkpoint version are not complete (most likely an incomplete multipart | ||
| // checkpoint). We should delete the files gathered so far and start fresh | ||
| // last seen checkpoint state | ||
| logger.info( | ||
| "{}: Incomplete checkpoint files found at version {}, ignoring the checkpoint" | ||
| + " files and adding them to potential log file delete list", | ||
| tablePath, | ||
| lastSeenCheckpointVersion); | ||
| potentialLogFilesToDelete.addAll(lastSeenCheckpointFiles); | ||
| lastSeenCheckpointFiles.clear(); | ||
| } | ||
|
|
||
| lastSeenCheckpointFiles.add(nextFile.getPath()); | ||
| lastSeenCheckpointVersion = newLastSeenCheckpointVersion; | ||
| } | ||
| // Ignore non-delta and non-checkpoint files. | ||
| } | ||
| } | ||
| logger.info("{}: Deleted {} log files older than {}", tablePath, numDeleted, fileCutOffTime); | ||
| return numDeleted; | ||
| } | ||
|
|
||
| private static CloseableIterator<FileStatus> listDeltaLogs(Engine engine, Path tablePath) | ||
| throws IOException { | ||
| Path logPath = new Path(tablePath, "_delta_log"); | ||
| // TODO: Currently we don't update the timestamps of files to be monotonically increasing. | ||
| // In future we can do something similar to Delta Spark to make the timestamps monotonically | ||
| // increasing. See `BufferingLogDeletionIterator` in Delta Spark. | ||
| return engine.getFileSystemClient().listFrom(FileNames.listingPrefix(logPath, 0)); | ||
| } | ||
|
|
||
| private static int deleteLogFiles(Engine engine, List<String> logFiles) throws IOException { | ||
| int numDeleted = 0; | ||
| for (String logFile : logFiles) { | ||
| if (wrapEngineExceptionThrowsIO( | ||
| () -> engine.getFileSystemClient().delete(logFile), | ||
| "Failed to delete the log file as part of the metadata cleanup %s", | ||
| logFile)) { | ||
| numDeleted++; | ||
| } | ||
| } | ||
| return numDeleted; | ||
| } | ||
| } |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Oops, something went wrong.