smengcl commented on code in PR #9133: URL: https://github.com/apache/ozone/pull/9133#discussion_r2427601910
########## hadoop-ozone/ozone-manager/src/main/java/org/apache/hadoop/ozone/om/SnapshotDefragService.java: ########## @@ -0,0 +1,365 @@ +/* + * 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.ozone.om; + +import static org.apache.hadoop.ozone.om.OMConfigKeys.SNAPSHOT_DEFRAG_LIMIT_PER_TASK; +import static org.apache.hadoop.ozone.om.OMConfigKeys.SNAPSHOT_DEFRAG_LIMIT_PER_TASK_DEFAULT; +import static org.apache.hadoop.ozone.om.lock.OzoneManagerLock.FlatResource.SNAPSHOT_GC_LOCK; + +import com.google.common.annotations.VisibleForTesting; +import java.io.File; +import java.io.IOException; +import java.util.Collections; +import java.util.Iterator; +import java.util.Optional; +import java.util.UUID; +import java.util.concurrent.TimeUnit; +import java.util.concurrent.atomic.AtomicBoolean; +import java.util.concurrent.atomic.AtomicLong; +import org.apache.hadoop.hdds.conf.OzoneConfiguration; +import org.apache.hadoop.hdds.utils.BackgroundService; +import org.apache.hadoop.hdds.utils.BackgroundTask; +import org.apache.hadoop.hdds.utils.BackgroundTaskQueue; +import org.apache.hadoop.hdds.utils.BackgroundTaskResult; +import org.apache.hadoop.hdds.utils.BackgroundTaskResult.EmptyTaskResult; +import org.apache.hadoop.hdds.utils.db.Table; +import org.apache.hadoop.hdds.utils.db.managed.ManagedRawSSTFileReader; +import org.apache.hadoop.ozone.lock.BootstrapStateHandler; +import org.apache.hadoop.ozone.om.exceptions.OMException; +import org.apache.hadoop.ozone.om.helpers.SnapshotInfo; +import org.apache.hadoop.ozone.om.lock.IOzoneManagerLock; +import org.apache.hadoop.ozone.om.snapshot.MultiSnapshotLocks; +import org.apache.ratis.util.function.UncheckedAutoCloseableSupplier; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +/** + * Background service for defragmenting snapshots in the active snapshot chain. + * When snapshots are taken, they capture the entire OM RocksDB state but may contain + * fragmented data. This service defragments snapshots by creating new compacted + * RocksDB instances with only the necessary data for tracked column families. + * <p> + * The service processes snapshots in the active chain sequentially, starting with + * the first non-defragmented snapshot. For the first snapshot in the chain, it + * performs a full defragmentation by copying all keys. For subsequent snapshots, + * it uses incremental defragmentation based on diffs from the previous defragmented + * snapshot. + */ +public class SnapshotDefragService extends BackgroundService + implements BootstrapStateHandler { + + private static final Logger LOG = + LoggerFactory.getLogger(SnapshotDefragService.class); + + // Use only a single thread for snapshot defragmentation to avoid conflicts + private static final int DEFRAG_CORE_POOL_SIZE = 1; + + private final OzoneManager ozoneManager; + private SnapshotChainManager snapshotChainManager; + private final AtomicLong runCount = new AtomicLong(0); + + // Number of snapshots to be processed in a single iteration + private final long snapshotLimitPerTask; + + private final AtomicLong snapshotsDefraggedCount; + private final AtomicBoolean running; + + private final MultiSnapshotLocks snapshotIdLocks; + + private final BootstrapStateHandler.Lock lock = new BootstrapStateHandler.Lock(); + + public SnapshotDefragService(long interval, TimeUnit unit, long serviceTimeout, + OzoneManager ozoneManager, OzoneConfiguration configuration) { + super("SnapshotDefragService", interval, unit, DEFRAG_CORE_POOL_SIZE, + serviceTimeout, ozoneManager.getThreadNamePrefix()); + this.ozoneManager = ozoneManager; + this.snapshotLimitPerTask = configuration + .getLong(SNAPSHOT_DEFRAG_LIMIT_PER_TASK, + SNAPSHOT_DEFRAG_LIMIT_PER_TASK_DEFAULT); + snapshotsDefraggedCount = new AtomicLong(0); + running = new AtomicBoolean(false); + IOzoneManagerLock omLock = ozoneManager.getMetadataManager().getLock(); + this.snapshotIdLocks = new MultiSnapshotLocks(omLock, SNAPSHOT_GC_LOCK, true); + } + + @Override + public void start() { + running.set(true); + super.start(); + } + + @VisibleForTesting + public void pause() { + running.set(false); + } + + @VisibleForTesting + public void resume() { + running.set(true); + } + + /** + * Checks if rocks-tools native library is available. + */ + private boolean isRocksToolsNativeLibAvailable() { + try { + return ManagedRawSSTFileReader.tryLoadLibrary(); + } catch (Exception e) { + LOG.warn("Failed to check native code availability", e); + return false; + } + } + + /** + * Checks if a snapshot needs defragmentation by examining its YAML metadata. + */ + private boolean needsDefragmentation(SnapshotInfo snapshotInfo) { + String snapshotPath = OmSnapshotManager.getSnapshotPath( + ozoneManager.getConfiguration(), snapshotInfo); + + try { + // Read YAML metadata using the correct API + File yamlFile = new File(snapshotPath + ".yaml"); + OmSnapshotLocalDataYaml yamlData = + OmSnapshotLocalDataYaml.getFromYamlFile(ozoneManager.getOmSnapshotManager(), yamlFile); + + // Check if snapshot needs compaction (defragmentation) + boolean needsDefrag = yamlData.getNeedsDefrag(); + LOG.debug("Snapshot {} needsDefragmentation field value: {}", + snapshotInfo.getName(), needsDefrag); + + return needsDefrag; + } catch (IOException e) { + LOG.warn("Failed to read YAML metadata for snapshot {}, assuming defrag needed", + snapshotInfo.getName(), e); + return true; + } + } + + /** + * Performs full defragmentation for the first snapshot in the chain. + * This is a simplified implementation that demonstrates the concept. + */ + private void performFullDefragmentation(SnapshotInfo snapshotInfo, + OmSnapshot omSnapshot) throws IOException { + + // TODO: Implement full defragmentation + } + + /** + * Performs incremental defragmentation using diff from previous defragmented snapshot. + */ + private void performIncrementalDefragmentation(SnapshotInfo currentSnapshot, + SnapshotInfo previousDefraggedSnapshot, OmSnapshot currentOmSnapshot) + throws IOException { + + // TODO: Implement incremental defragmentation + } + + private final class SnapshotDefragTask implements BackgroundTask { + + @Override + public BackgroundTaskResult call() throws Exception { + // Check OM leader and readiness + if (shouldRun()) { + final long count = runCount.incrementAndGet(); + if (LOG.isDebugEnabled()) { + LOG.debug("Initiating Snapshot Defragmentation Task: run # {}", count); + } + triggerSnapshotDefragOnce(); + } + + return EmptyTaskResult.newResult(); + } + } + + public synchronized boolean triggerSnapshotDefragOnce() throws IOException { + // Check if rocks-tools native lib is available + if (!isRocksToolsNativeLibAvailable()) { + LOG.warn("Rocks-tools native library is not available. " + + "Stopping SnapshotDefragService."); + return false; + } + + Optional<OmSnapshotManager> snapshotManager = Optional.ofNullable(ozoneManager) + .map(OzoneManager::getOmSnapshotManager); + if (!snapshotManager.isPresent()) { + LOG.debug("OmSnapshotManager not available, skipping defragmentation task"); + return false; + } + + // Get the SnapshotChainManager to iterate through the global snapshot chain + // Set this each time the task runs just in case OmMetadataManager is restarted + snapshotChainManager = ((OmMetadataManagerImpl) ozoneManager.getMetadataManager()).getSnapshotChainManager(); + + final Table<String, SnapshotInfo> snapshotInfoTable = + ozoneManager.getMetadataManager().getSnapshotInfoTable(); + + // Use iterator(false) to iterate forward through the snapshot chain + Iterator<UUID> snapshotIterator = snapshotChainManager.iterator(false); + + long snapshotLimit = snapshotLimitPerTask; + + while (snapshotLimit > 0 && running.get() && snapshotIterator.hasNext()) { + // Get SnapshotInfo for the current snapshot in the chain + UUID snapshotId = snapshotIterator.next(); + String snapshotTableKey = snapshotChainManager.getTableKey(snapshotId); + SnapshotInfo snapshotToDefrag = snapshotInfoTable.get(snapshotTableKey); + if (snapshotToDefrag == null) { + LOG.warn("Snapshot with ID '{}' not found in snapshot info table", snapshotId); + continue; + } + + // Skip deleted snapshots + if (snapshotToDefrag.getSnapshotStatus() == SnapshotInfo.SnapshotStatus.SNAPSHOT_DELETED) { + LOG.debug("Skipping deleted snapshot: {} (ID: {})", + snapshotToDefrag.getName(), snapshotToDefrag.getSnapshotId()); + continue; + } + + // Check if this snapshot needs defragmentation + if (!needsDefragmentation(snapshotToDefrag)) { + LOG.debug("Skipping already defragged snapshot: {} (ID: {})", + snapshotToDefrag.getName(), snapshotToDefrag.getSnapshotId()); + continue; + } + + LOG.info("Will defrag snapshot: {} (ID: {})", + snapshotToDefrag.getName(), snapshotToDefrag.getSnapshotId()); + + // Acquire MultiSnapshotLocks + if (!snapshotIdLocks.acquireLock(Collections.singletonList(snapshotToDefrag.getSnapshotId())) + .isLockAcquired()) { + LOG.error("Abort. Failed to acquire lock on snapshot: {} (ID: {})", + snapshotToDefrag.getName(), snapshotToDefrag.getSnapshotId()); + break; + } + + try { + LOG.info("Processing snapshot defragmentation for: {} (ID: {})", + snapshotToDefrag.getName(), snapshotToDefrag.getSnapshotId()); + + // Get snapshot through SnapshotCache for proper locking + try (UncheckedAutoCloseableSupplier<OmSnapshot> snapshotSupplier = + snapshotManager.get().getSnapshot(snapshotTableKey, false)) { Review Comment: Using `getSnapshot(UUID)` instead. thx! -- 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]
