sadanand48 commented on code in PR #9132: URL: https://github.com/apache/ozone/pull/9132#discussion_r2594510912
########## hadoop-hdds/framework/src/main/java/org/apache/hadoop/hdds/utils/db/InodeMetadataRocksDBCheckpoint.java: ########## @@ -0,0 +1,151 @@ +/* + * 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.hadoop.hdds.utils.db; + +import java.io.File; +import java.io.IOException; +import java.nio.file.Files; +import java.nio.file.Path; +import java.nio.file.Paths; +import java.util.ArrayList; +import java.util.List; +import java.util.stream.Collectors; +import java.util.stream.Stream; +import org.apache.commons.io.FileUtils; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +/** + * RocksDB checkpoint implementation that uses hardlinks to optimize disk space + * for inode-based metadata checkpoints. + * + * <p>During construction, reads a hardlink mapping file and creates hardlinks + * from checkpoint files to the checkpoint_data directory. Original files are + * then deleted since they're accessible via hardlinks, saving disk space while + * maintaining checkpoint functionality. + * </p> + */ +public class InodeMetadataRocksDBCheckpoint implements DBCheckpoint { + + private final Path checkpointLocation; + private final long checkpointTimestamp = System.currentTimeMillis(); + private final long latestSequenceNumber = -1; + private final long checkpointCreationTimeTaken = 0L; + + private static final Logger LOG = + LoggerFactory.getLogger(InodeMetadataRocksDBCheckpoint.class); + + public static final String OM_HARDLINK_FILE = "hardLinkFile"; + + public InodeMetadataRocksDBCheckpoint(Path checkpointLocation) throws IOException { + this.checkpointLocation = checkpointLocation; + installHardLinks(); + } + + @Override + public Path getCheckpointLocation() { + return this.checkpointLocation; + } + + @Override + public long getCheckpointTimestamp() { + return this.checkpointTimestamp; + } + + @Override + public long getLatestSequenceNumber() { + return this.latestSequenceNumber; + } + + @Override + public long checkpointCreationTimeTaken() { + return this.checkpointCreationTimeTaken; + } + + @Override + public void cleanupCheckpoint() throws IOException { + LOG.info("Cleaning up RocksDB checkpoint at {}", + checkpointLocation.toString()); + FileUtils.deleteDirectory(checkpointLocation.toFile()); + } + + private void installHardLinks() throws IOException { + File hardLinkFile = new File(checkpointLocation.toFile(), + OM_HARDLINK_FILE); + + if (!hardLinkFile.exists()) { + LOG.error("Hardlink file : {} does not exist.", hardLinkFile); + return; + } + + // Track source files that need to be deleted after hardlink creation + List<Path> sourceFilesToDelete = new ArrayList<>(); + + // Read file and create hardlinks directly in checkpointLocation + try (Stream<String> s = Files.lines(hardLinkFile.toPath())) { + List<String> lines = s.collect(Collectors.toList()); + + // Create hardlinks directly in checkpointLocation + for (String l : lines) { + String[] parts = l.split("\t"); + if (parts.length != 2) { + LOG.warn("Skipping malformed line in hardlink file: {}", l); + continue; + } + String to = parts[0]; // Destination path (relative) + String from = parts[1]; // Source path (relative to checkpointLocation) + + Path sourcePath = Paths.get(checkpointLocation.toString(), from); + Path targetPath = Paths.get(checkpointLocation.toString(), to); + + // Track source file for later deletion + if (Files.exists(sourcePath)) { + sourceFilesToDelete.add(sourcePath); + } + + // Make parent directory if it doesn't exist + Path parent = targetPath.getParent(); + if (parent != null && !Files.exists(parent)) { Review Comment: this gives me a findbugs warning if not -- 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]
