StefanRRichter commented on a change in pull request #7674: [FLINK-10043] [State Backends] Refactor RocksDBKeyedStateBackend object construction/initialization/restore code URL: https://github.com/apache/flink/pull/7674#discussion_r258385521
########## File path: flink-state-backends/flink-statebackend-rocksdb/src/main/java/org/apache/flink/contrib/streaming/state/restore/RocksDBIncrementalRestoreOperation.java ########## @@ -0,0 +1,507 @@ +/* + * 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.flink.contrib.streaming.state.restore; + +import org.apache.flink.configuration.ConfigConstants; +import org.apache.flink.contrib.streaming.state.RocksDBIncrementalCheckpointUtils; +import org.apache.flink.contrib.streaming.state.RocksDBKeySerializationUtils; +import org.apache.flink.contrib.streaming.state.RocksDBNativeMetricOptions; +import org.apache.flink.contrib.streaming.state.RocksDBOperationUtils; +import org.apache.flink.contrib.streaming.state.RocksDBStateDownloader; +import org.apache.flink.contrib.streaming.state.RocksDBWriteBatchWrapper; +import org.apache.flink.contrib.streaming.state.RocksIteratorWrapper; +import org.apache.flink.contrib.streaming.state.StateColumnFamilyHandle; +import org.apache.flink.core.fs.CloseableRegistry; +import org.apache.flink.core.fs.FSDataInputStream; +import org.apache.flink.core.fs.FileStatus; +import org.apache.flink.core.fs.FileSystem; +import org.apache.flink.core.fs.Path; +import org.apache.flink.core.memory.DataInputView; +import org.apache.flink.core.memory.DataInputViewStreamWrapper; +import org.apache.flink.metrics.MetricGroup; +import org.apache.flink.runtime.state.BackendBuildingException; +import org.apache.flink.runtime.state.DirectoryStateHandle; +import org.apache.flink.runtime.state.IncrementalKeyedStateHandle; +import org.apache.flink.runtime.state.IncrementalLocalKeyedStateHandle; +import org.apache.flink.runtime.state.KeyGroupRange; +import org.apache.flink.runtime.state.KeyedBackendSerializationProxy; +import org.apache.flink.runtime.state.KeyedStateHandle; +import org.apache.flink.runtime.state.StateHandleID; +import org.apache.flink.runtime.state.StateSerializerProvider; +import org.apache.flink.runtime.state.StreamStateHandle; +import org.apache.flink.runtime.state.metainfo.StateMetaInfoSnapshot; +import org.apache.flink.util.IOUtils; + +import org.rocksdb.ColumnFamilyDescriptor; +import org.rocksdb.ColumnFamilyHandle; +import org.rocksdb.ColumnFamilyOptions; +import org.rocksdb.DBOptions; +import org.rocksdb.RocksDB; +import org.rocksdb.RocksDBException; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import javax.annotation.Nonnull; + +import java.io.File; +import java.io.IOException; +import java.nio.file.Files; +import java.nio.file.StandardCopyOption; +import java.util.ArrayList; +import java.util.Collection; +import java.util.List; +import java.util.Map; +import java.util.Objects; +import java.util.Set; +import java.util.SortedMap; +import java.util.TreeMap; +import java.util.UUID; + +import static org.apache.flink.contrib.streaming.state.snapshot.RocksSnapshotUtil.SST_FILE_SUFFIX; + +/** + * Encapsulates the process of restoring a RocksDB instance from an incremental snapshot. + */ +public class RocksDBIncrementalRestoreOperation<K> extends AbstractRocksDBRestoreOperation<K> { + private static final Logger LOG = LoggerFactory.getLogger(RocksDBIncrementalRestoreOperation.class); + + private final String operatorIdentifier; + protected final SortedMap<Long, Set<StateHandleID>> restoredSstFiles; + protected long lastCompletedCheckpointId; + protected UUID backendUID; + private boolean isKeySerializerCompatibilityChecked; + + public RocksDBIncrementalRestoreOperation( + String operatorIdentifier, + KeyGroupRange keyGroupRange, + int keyGroupPrefixBytes, + int numberOfTransferringThreads, + CloseableRegistry cancelStreamRegistry, + ClassLoader userCodeClassLoader, + Map<String, StateColumnFamilyHandle> kvStateInformation, + StateSerializerProvider<K> keySerializerProvider, + File instanceBasePath, + File instanceRocksDBPath, + DBOptions dbOptions, + ColumnFamilyOptions columnOptions, + RocksDBNativeMetricOptions nativeMetricOptions, + MetricGroup metricGroup, + @Nonnull Collection<KeyedStateHandle> restoreStateHandles) { + super(keyGroupRange, + keyGroupPrefixBytes, + numberOfTransferringThreads, + cancelStreamRegistry, + userCodeClassLoader, + kvStateInformation, + keySerializerProvider, + instanceBasePath, + instanceRocksDBPath, + dbOptions, + columnOptions, + nativeMetricOptions, + metricGroup, + restoreStateHandles); + this.operatorIdentifier = operatorIdentifier; + this.restoredSstFiles = new TreeMap<>(); + this.lastCompletedCheckpointId = -1L; + this.backendUID = UUID.randomUUID(); + } + + /** + * Root method that branches for different implementations of {@link KeyedStateHandle}. + */ + @Override + public RocksDBRestoreResult restore() throws Exception { + + if (restoreStateHandles == null || restoreStateHandles.isEmpty()) { + return null; + } + + final KeyedStateHandle theFirstStateHandle = restoreStateHandles.iterator().next(); + + boolean isRescaling = (restoreStateHandles.size() > 1 || + !Objects.equals(theFirstStateHandle.getKeyGroupRange(), keyGroupRange)); + + if (isRescaling) { + restoreWithRescaling(restoreStateHandles); + } else { + restoreWithoutRescaling(theFirstStateHandle); + } + return new RocksDBRestoreResult(this.db, defaultColumnFamilyHandle, + nativeMetricMonitor, lastCompletedCheckpointId, backendUID, restoredSstFiles); + } + + /** + * Recovery from a single remote incremental state without rescaling. + */ + void restoreWithoutRescaling(KeyedStateHandle rawStateHandle) throws Exception { + // 1. Prepare for restore without rescaling + Path temporaryRestoreInstancePath = new Path( + instanceBasePath.getAbsolutePath(), + UUID.randomUUID().toString()); // used as restore source for IncrementalKeyedStateHandle + RocksDBIncrementalRestorePrepareResult prepareResult = prepareFiles(rawStateHandle, temporaryRestoreInstancePath); + Path restoreSourcePath = prepareResult.getLocalKeyedStateHandle().getDirectoryStateHandle().getDirectory(); + if (rawStateHandle instanceof IncrementalKeyedStateHandle) { + backendUID = ((IncrementalKeyedStateHandle) rawStateHandle).getBackendIdentifier(); + } else { + backendUID = ((IncrementalLocalKeyedStateHandle) rawStateHandle).getBackendIdentifier(); + } + LOG.debug("Restoring keyed backend uid in operator {} from incremental snapshot to {}.", + this.operatorIdentifier, this.backendUID); + if (!instanceRocksDBPath.mkdirs()) { + String errMsg = "Could not create RocksDB data directory: " + instanceBasePath.getAbsolutePath(); + LOG.error(errMsg); + throw new IOException(errMsg); + } + try { + restoreInstanceDirectoryFromPath(restoreSourcePath, dbPath); + } finally { + FileSystem restoreFileSystem = restoreSourcePath.getFileSystem(); + if (restoreFileSystem.exists(restoreSourcePath)) { + restoreFileSystem.delete(restoreSourcePath, true); + } + } + // 2. Open db instance + openDB(); + // 3. Use the restore sst files as the base for succeeding checkpoints + IncrementalLocalKeyedStateHandle restoreStateHandle = prepareResult.getLocalKeyedStateHandle(); + restoredSstFiles.put( + restoreStateHandle.getCheckpointId(), + restoreStateHandle.getSharedStateHandleIDs()); + lastCompletedCheckpointId = restoreStateHandle.getCheckpointId(); + // 4. Register column family handles + registerCFHandles(prepareResult.getStateMetaInfoSnapshots()); + } + + private void registerCFHandles(List<StateMetaInfoSnapshot> metaInfoSnapshots) + throws BackendBuildingException { + // Register CF handlers + for (int i = 0; i < metaInfoSnapshots.size(); ++i) { + try { + getOrRegisterStateColumnFamilyHandle( + columnFamilyDescriptors.get(i), + columnFamilyHandles.get(i), + metaInfoSnapshots.get(i)); + } catch (RocksDBException e) { + String errMsg = "Failed to register CF handle."; + LOG.error(errMsg, e); + throw new BackendBuildingException(errMsg, e); + } + } + } + + public RocksDBIncrementalRestorePrepareResult prepareFiles( + KeyedStateHandle rawStateHandle, + Path restoreInstancePath) throws IOException { + IncrementalLocalKeyedStateHandle localKeyedStateHandle; + List<StateMetaInfoSnapshot> stateMetaInfoSnapshots; + try { + KeyedBackendSerializationProxy<K> serializationProxy; + if (rawStateHandle instanceof IncrementalKeyedStateHandle) { + IncrementalKeyedStateHandle restoreStateHandle = (IncrementalKeyedStateHandle) rawStateHandle; + + // read state data. + try (RocksDBStateDownloader rocksDBStateDownloader = + new RocksDBStateDownloader(numberOfTransferringThreads)) { + rocksDBStateDownloader.transferAllStateDataToDirectory( + restoreStateHandle, + restoreInstancePath, + cancelStreamRegistry); + } + + serializationProxy = readMetaData(restoreStateHandle.getMetaStateHandle()); + stateMetaInfoSnapshots = serializationProxy.getStateMetaInfoSnapshots(); + columnFamilyDescriptors = createAndRegisterColumnFamilyDescriptors(stateMetaInfoSnapshots, columnOptions); + + // since we transferred all remote state to a local directory, we can use the same code as for + // local recovery. + localKeyedStateHandle = new IncrementalLocalKeyedStateHandle( + restoreStateHandle.getBackendIdentifier(), + restoreStateHandle.getCheckpointId(), + new DirectoryStateHandle(restoreInstancePath), + restoreStateHandle.getKeyGroupRange(), + restoreStateHandle.getMetaStateHandle(), + restoreStateHandle.getSharedState().keySet()); + } else if (rawStateHandle instanceof IncrementalLocalKeyedStateHandle) { + // Recovery from local incremental state. + localKeyedStateHandle = (IncrementalLocalKeyedStateHandle) rawStateHandle; + serializationProxy = readMetaData(localKeyedStateHandle.getMetaDataState()); + stateMetaInfoSnapshots = serializationProxy.getStateMetaInfoSnapshots(); + columnFamilyDescriptors = createAndRegisterColumnFamilyDescriptors(stateMetaInfoSnapshots, columnOptions); + } else { + throw new IllegalStateException("Unexpected state handle type, " + + "expected " + IncrementalKeyedStateHandle.class + " or " + IncrementalLocalKeyedStateHandle.class + + ", but found " + rawStateHandle.getClass()); + } + } catch (Exception e) { + // clean up + FileSystem restoreFileSystem = restoreInstancePath.getFileSystem(); + if (restoreFileSystem.exists(restoreInstancePath)) { + restoreFileSystem.delete(restoreInstancePath, true); Review comment: Very good addition! I would suggest to consider error handling for all the exception that can happen when dealing with filesystem and delete here, because they can hide the original exception, and the log statement would not be reached as well. I think you can see better when changing this method from `throws IOException` to `throws BackendBuildingException` ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org With regards, Apache Git Services
