com.uber.hoodie.io.HoodieCleanHelper Maven / Gradle / Ivy
/*
* Copyright (c) 2016 Uber Technologies, Inc. ([email protected])
*
* 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 com.uber.hoodie.io;
import com.uber.hoodie.common.model.FileSlice;
import com.uber.hoodie.common.model.HoodieCleaningPolicy;
import com.uber.hoodie.common.model.HoodieDataFile;
import com.uber.hoodie.common.model.HoodieFileGroup;
import com.uber.hoodie.common.model.HoodieRecordPayload;
import com.uber.hoodie.common.model.HoodieTableType;
import com.uber.hoodie.common.table.HoodieTimeline;
import com.uber.hoodie.common.table.TableFileSystemView;
import com.uber.hoodie.common.table.timeline.HoodieInstant;
import com.uber.hoodie.config.HoodieWriteConfig;
import com.uber.hoodie.table.HoodieTable;
import org.apache.hadoop.fs.FileSystem;
import org.apache.log4j.LogManager;
import org.apache.log4j.Logger;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Optional;
import java.util.stream.Collectors;
/**
* Cleaner is responsible for garbage collecting older files in a given partition path, such that
*
* 1) It provides sufficient time for existing queries running on older versions, to finish
*
* 2) It bounds the growth of the files in the file system
*
* TODO: Should all cleaning be done based on {@link com.uber.hoodie.common.model.HoodieCommitMetadata}
*/
public class HoodieCleanHelper> {
private static Logger logger = LogManager.getLogger(HoodieCleanHelper.class);
private final TableFileSystemView fileSystemView;
private final HoodieTimeline commitTimeline;
private HoodieTable hoodieTable;
private HoodieWriteConfig config;
private FileSystem fs;
public HoodieCleanHelper(HoodieTable hoodieTable, HoodieWriteConfig config) {
this.hoodieTable = hoodieTable;
this.fileSystemView = hoodieTable.getCompletedFileSystemView();
this.commitTimeline = hoodieTable.getCompletedCommitTimeline();
this.config = config;
this.fs = hoodieTable.getFs();
}
/**
* Selects the older versions of files for cleaning, such that it bounds the number of versions of each file.
* This policy is useful, if you are simply interested in querying the table, and you don't want too many
* versions for a single file (i.e run it with versionsRetained = 1)
*
* @param partitionPath
* @return
* @throws IOException
*/
private List getFilesToCleanKeepingLatestVersions(String partitionPath)
throws IOException {
logger.info("Cleaning " + partitionPath + ", retaining latest " + config
.getCleanerFileVersionsRetained() + " file versions. ");
List fileGroups =
fileSystemView.getAllFileGroups(partitionPath)
.collect(Collectors.toList());
List deletePaths = new ArrayList<>();
// Collect all the datafiles savepointed by all the savepoints
List savepointedFiles = hoodieTable.getSavepoints().stream()
.flatMap(s -> hoodieTable.getSavepointedDataFiles(s)).collect(Collectors.toList());
for (HoodieFileGroup fileGroup : fileGroups) {
int keepVersions = config.getCleanerFileVersionsRetained();
Iterator fileSliceIterator = fileGroup.getAllFileSlices().iterator();
while (fileSliceIterator.hasNext() && keepVersions > 0) {
// Skip this most recent version
FileSlice nextSlice = fileSliceIterator.next();
HoodieDataFile dataFile = nextSlice.getDataFile().get();
if(savepointedFiles.contains(dataFile.getFileName())) {
// do not clean up a savepoint data file
continue;
}
keepVersions--;
}
// Delete the remaining files
while (fileSliceIterator.hasNext()) {
FileSlice nextSlice = fileSliceIterator.next();
HoodieDataFile dataFile = nextSlice.getDataFile().get();
deletePaths.add(dataFile.getFileStatus().getPath().toString());
if (hoodieTable.getMetaClient().getTableType()
== HoodieTableType.MERGE_ON_READ) {
// If merge on read, then clean the log files for the commits as well
deletePaths.addAll(nextSlice.getLogFiles()
.map(file -> file.getPath().toString())
.collect(Collectors.toList()));
}
}
}
return deletePaths;
}
/**
* Selects the versions for file for cleaning, such that it
*
* - Leaves the latest version of the file untouched
* - For older versions,
* - It leaves all the commits untouched which has occured in last config.getCleanerCommitsRetained() commits
* - It leaves ONE commit before this window. We assume that the max(query execution time) == commit_batch_time * config.getCleanerCommitsRetained(). This is 12 hours by default.
* This is essential to leave the file used by the query thats running for the max time.
*
* This provides the effect of having lookback into all changes that happened in the last X
* commits. (eg: if you retain 24 commits, and commit batch time is 30 mins, then you have 12 hrs of lookback)
*
* This policy is the default.
*
* @param partitionPath
* @return
* @throws IOException
*/
private List getFilesToCleanKeepingLatestCommits(String partitionPath)
throws IOException {
int commitsRetained = config.getCleanerCommitsRetained();
logger.info(
"Cleaning " + partitionPath + ", retaining latest " + commitsRetained + " commits. ");
List deletePaths = new ArrayList<>();
// Collect all the datafiles savepointed by all the savepoints
List savepointedFiles = hoodieTable.getSavepoints().stream()
.flatMap(s -> hoodieTable.getSavepointedDataFiles(s)).collect(Collectors.toList());
// determine if we have enough commits, to start cleaning.
if (commitTimeline.countInstants() > commitsRetained) {
HoodieInstant earliestCommitToRetain = getEarliestCommitToRetain().get();
List fileGroups =
fileSystemView.getAllFileGroups(partitionPath)
.collect(Collectors.toList());
for (HoodieFileGroup fileGroup : fileGroups) {
List fileSliceList = fileGroup.getAllFileSlices().collect(Collectors.toList());
HoodieDataFile dataFile = fileSliceList.get(0).getDataFile().get();
String lastVersion = dataFile.getCommitTime();
String lastVersionBeforeEarliestCommitToRetain =
getLatestVersionBeforeCommit(fileSliceList, earliestCommitToRetain);
// Ensure there are more than 1 version of the file (we only clean old files from updates)
// i.e always spare the last commit.
for (FileSlice aSlice : fileSliceList) {
HoodieDataFile aFile = aSlice.getDataFile().get();
String fileCommitTime = aFile.getCommitTime();
if(savepointedFiles.contains(aFile.getFileName())) {
// do not clean up a savepoint data file
continue;
}
// Dont delete the latest commit and also the last commit before the earliest commit we are retaining
// The window of commit retain == max query run time. So a query could be running which still
// uses this file.
if (fileCommitTime.equals(lastVersion) || (
lastVersionBeforeEarliestCommitToRetain != null && fileCommitTime
.equals(lastVersionBeforeEarliestCommitToRetain))) {
// move on to the next file
continue;
}
// Always keep the last commit
if (HoodieTimeline.compareTimestamps(
earliestCommitToRetain.getTimestamp(),
fileCommitTime,
HoodieTimeline.GREATER)) {
// this is a commit, that should be cleaned.
deletePaths.add(aFile.getFileStatus().getPath().toString());
if (hoodieTable.getMetaClient().getTableType()
== HoodieTableType.MERGE_ON_READ) {
// If merge on read, then clean the log files for the commits as well
deletePaths.addAll(aSlice.getLogFiles()
.map(file -> file.getPath().toString())
.collect(Collectors.toList()));
}
}
}
}
}
return deletePaths;
}
/**
* Gets the latest version < commitTime. This version file could still be used by queries.
*/
private String getLatestVersionBeforeCommit(List fileSliceList,
HoodieInstant commitTime) {
for (FileSlice file : fileSliceList) {
String fileCommitTime = file.getDataFile().get().getCommitTime();
if (HoodieTimeline.compareTimestamps(commitTime.getTimestamp(), fileCommitTime,
HoodieTimeline.GREATER)) {
// fileList is sorted on the reverse, so the first commit we find <= commitTime is the one we want
return fileCommitTime;
}
}
// There is no version of this file which is <= commitTime
return null;
}
/**
* Returns files to be cleaned for the given partitionPath based on cleaning policy.
*/
public List getDeletePaths(String partitionPath) throws IOException {
HoodieCleaningPolicy policy = config.getCleanerPolicy();
List deletePaths;
if (policy == HoodieCleaningPolicy.KEEP_LATEST_COMMITS) {
deletePaths = getFilesToCleanKeepingLatestCommits(partitionPath);
} else if (policy == HoodieCleaningPolicy.KEEP_LATEST_FILE_VERSIONS) {
deletePaths = getFilesToCleanKeepingLatestVersions(partitionPath);
} else {
throw new IllegalArgumentException("Unknown cleaning policy : " + policy.name());
}
logger.info(
deletePaths.size() + " patterns used to delete in partition path:" + partitionPath);
return deletePaths;
}
/**
* Returns earliest commit to retain based on cleaning policy.
*/
public Optional getEarliestCommitToRetain() {
Optional earliestCommitToRetain = Optional.empty();
int commitsRetained = config.getCleanerCommitsRetained();
if (config.getCleanerPolicy() == HoodieCleaningPolicy.KEEP_LATEST_COMMITS
&& commitTimeline.countInstants() > commitsRetained) {
earliestCommitToRetain =
commitTimeline.nthInstant(commitTimeline.countInstants() - commitsRetained);
}
return earliestCommitToRetain;
}
}