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_r256834258
########## File path: flink-state-backends/flink-statebackend-rocksdb/src/main/java/org/apache/flink/contrib/streaming/state/RocksDBKeyedStateBackendBuilder.java ########## @@ -0,0 +1,502 @@ +/* + * 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; + +import org.apache.flink.annotation.VisibleForTesting; +import org.apache.flink.api.common.ExecutionConfig; +import org.apache.flink.api.common.typeutils.TypeSerializer; +import org.apache.flink.api.common.typeutils.TypeSerializerSchemaCompatibility; +import org.apache.flink.contrib.streaming.state.restore.RocksDBIncrementalRestoreOperation; +import org.apache.flink.contrib.streaming.state.restore.RocksDBIncrementalRestorePrepareResult; +import org.apache.flink.contrib.streaming.state.snapshot.RocksDBSnapshotStrategyBase; +import org.apache.flink.contrib.streaming.state.snapshot.RocksFullSnapshotStrategy; +import org.apache.flink.contrib.streaming.state.snapshot.RocksIncrementalSnapshotStrategy; +import org.apache.flink.core.fs.CloseableRegistry; +import org.apache.flink.core.fs.FileSystem; +import org.apache.flink.core.fs.Path; +import org.apache.flink.metrics.MetricGroup; +import org.apache.flink.runtime.query.TaskKvStateRegistry; +import org.apache.flink.runtime.state.AbstractKeyedStateBackendBuilder; +import org.apache.flink.runtime.state.BackendBuildingException; +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.KeyedStateHandle; +import org.apache.flink.runtime.state.LocalRecoveryConfig; +import org.apache.flink.runtime.state.PriorityQueueSetFactory; +import org.apache.flink.runtime.state.StateHandleID; +import org.apache.flink.runtime.state.heap.HeapPriorityQueueSetFactory; +import org.apache.flink.runtime.state.metainfo.StateMetaInfoSnapshot; +import org.apache.flink.runtime.state.ttl.TtlTimeProvider; +import org.apache.flink.util.FileUtils; +import org.apache.flink.util.IOUtils; +import org.apache.flink.util.Preconditions; +import org.apache.flink.util.ResourceGuard; +import org.apache.flink.util.StateMigrationException; + +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.rocksdb.WriteOptions; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import java.io.File; +import java.io.IOException; +import java.util.ArrayList; +import java.util.Collection; +import java.util.Collections; +import java.util.LinkedHashMap; +import java.util.List; +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.RocksDBKeyedStateBackend.MERGE_OPERATOR_NAME; + +/** + * Builder class for {@link RocksDBKeyedStateBackend} which handles all necessary initializations and clean ups. + * + * @param <K> The data type that the key serializer serializes. + */ +public class RocksDBKeyedStateBackendBuilder<K> extends AbstractKeyedStateBackendBuilder<K> { + + private static final Logger LOG = LoggerFactory.getLogger(RocksDBKeyedStateBackendBuilder.class); + public static final String DB_INSTANCE_DIR_STRING = "db"; + + /** String that identifies the operator that owns this backend. */ + private final String operatorIdentifier; + private final RocksDBStateBackend.PriorityQueueStateType priorityQueueStateType; + /** The configuration of local recovery. */ + private final LocalRecoveryConfig localRecoveryConfig; + + /** The column family options from the options factory. */ + private final ColumnFamilyOptions columnFamilyOptions; + + /** The DB options from the options factory. */ + private final DBOptions dbOptions; + + /** Path where this configured instance stores its data directory. */ + private final File instanceBasePath; + + /** Path where this configured instance stores its RocksDB database. */ + private final File instanceRocksDBPath; + + private final MetricGroup metricGroup; + + /** True if incremental checkpointing is enabled. */ + private boolean enableIncrementalCheckpointing = false; + private RocksDBNativeMetricOptions nativeMetricOptions = new RocksDBNativeMetricOptions(); + private int numberOfTransferingThreads = RocksDBOptions.CHECKPOINT_TRANSFER_THREAD_NUM.defaultValue(); + + // The DB instance to initiate and parameters for initialization + private RocksDB db; + private boolean dbInitRequired = true; + private List<ColumnFamilyHandle> columnFamilyHandles = new ArrayList<>(1); + private List<ColumnFamilyDescriptor> columnFamilyDescriptors = Collections.emptyList(); + private final String dbPath; + private RocksDBSnapshotStrategyBase<K> checkpointSnapshotStrategy; + private RocksDBSnapshotStrategyBase<K> savepointSnapshotStrategy; + + // Variables for snapshot strategy when incremental checkpoint is enabled + private UUID backendUID = UUID.randomUUID(); + private SortedMap<Long, Set<StateHandleID>> materializedSstFiles = new TreeMap<>(); + private long lastCompletedCheckpointId = -1L; + + public RocksDBKeyedStateBackendBuilder( + String operatorIdentifier, + ClassLoader userCodeClassLoader, + File instanceBasePath, + DBOptions dbOptions, + ColumnFamilyOptions columnFamilyOptions, + TaskKvStateRegistry kvStateRegistry, + TypeSerializer<K> keySerializer, + int numberOfKeyGroups, + KeyGroupRange keyGroupRange, + ExecutionConfig executionConfig, + LocalRecoveryConfig localRecoveryConfig, + RocksDBStateBackend.PriorityQueueStateType priorityQueueStateType, + TtlTimeProvider ttlTimeProvider, + MetricGroup metricGroup, + Collection<KeyedStateHandle> stateHandles) { + + super(kvStateRegistry, keySerializer, userCodeClassLoader, + numberOfKeyGroups, keyGroupRange, executionConfig, ttlTimeProvider, stateHandles); + + this.operatorIdentifier = operatorIdentifier; + this.priorityQueueStateType = priorityQueueStateType; + this.localRecoveryConfig = localRecoveryConfig; + // ensure that we use the right merge operator, because other code relies on this + this.columnFamilyOptions = Preconditions.checkNotNull(columnFamilyOptions) + .setMergeOperatorName(MERGE_OPERATOR_NAME); + this.dbOptions = dbOptions; + this.instanceBasePath = instanceBasePath; + this.instanceRocksDBPath = new File(instanceBasePath, DB_INSTANCE_DIR_STRING); + this.dbPath = instanceRocksDBPath.getAbsolutePath(); + this.metricGroup = metricGroup; + } + + @VisibleForTesting + RocksDBKeyedStateBackendBuilder( + String operatorIdentifier, + ClassLoader userCodeClassLoader, + File instanceBasePath, + DBOptions dbOptions, + ColumnFamilyOptions columnFamilyOptions, + TaskKvStateRegistry kvStateRegistry, + TypeSerializer<K> keySerializer, + int numberOfKeyGroups, + KeyGroupRange keyGroupRange, + ExecutionConfig executionConfig, + LocalRecoveryConfig localRecoveryConfig, + RocksDBStateBackend.PriorityQueueStateType priorityQueueStateType, + TtlTimeProvider ttlTimeProvider, + MetricGroup metricGroup, + Collection<KeyedStateHandle> stateHandles, + RocksDB db) { + this(operatorIdentifier, userCodeClassLoader, instanceBasePath, dbOptions, + columnFamilyOptions, kvStateRegistry, keySerializer, numberOfKeyGroups, keyGroupRange, + executionConfig, localRecoveryConfig, priorityQueueStateType, ttlTimeProvider, metricGroup, stateHandles); + this.db = db; + this.dbInitRequired = false; + } + + public RocksDBKeyedStateBackendBuilder<K> setEnableIncrementalCheckpointing(boolean enableIncrementalCheckpointing) { + this.enableIncrementalCheckpointing = enableIncrementalCheckpointing; + return this; + } + + public RocksDBKeyedStateBackendBuilder<K> setNativeMetricOptions(RocksDBNativeMetricOptions nativeMetricOptions) { + this.nativeMetricOptions = nativeMetricOptions; + return this; + } + + public RocksDBKeyedStateBackendBuilder<K> setNumberOfTransferingThreads(int numberOfTransferingThreads) { + this.numberOfTransferingThreads = numberOfTransferingThreads; + return this; + } + + private static void checkAndCreateDirectory(File directory) throws IOException { + if (directory.exists()) { + if (!directory.isDirectory()) { + throw new IOException("Not a directory: " + directory); + } + } else if (!directory.mkdirs()) { + throw new IOException(String.format("Could not create RocksDB data directory at %s.", directory)); + } + } + + public RocksDBKeyedStateBackend<K> build() throws BackendBuildingException { + RocksDBKeyedStateBackend<K> backend = null; + RocksDBWriteBatchWrapper writeBatchWrapper = null; + ColumnFamilyHandle defaultColumnFamilyHandle = null; + RocksDBNativeMetricMonitor nativeMetricMonitor = null; + CloseableRegistry cancelStreamRegistry = new CloseableRegistry(); + //The write options to use in the states. We disable write ahead logging. + WriteOptions writeOptions = new WriteOptions().setDisableWAL(true); + LinkedHashMap<String, StateColumnFamilyHandle> kvStateInformation = new LinkedHashMap<>(); + ResourceGuard rocksDBResourceGuard = new ResourceGuard(); + // Number of bytes required to prefix the key groups. + int keyGroupPrefixBytes = RocksDBKeySerializationUtils.computeRequiredBytesInKeyGroupPrefix(numberOfKeyGroups); + try { + prepareDirectories(); + + RocksDBIncrementalRestorePrepareResult restorePrepareResult = checkAndPrepareRestore(cancelStreamRegistry); + + if (dbInitRequired) { + db = RocksDBOperationUtils.openDB(dbPath, columnFamilyDescriptors, + columnFamilyHandles, columnFamilyOptions, dbOptions); + // remove the default column family which is located at the first index + defaultColumnFamilyHandle = columnFamilyHandles.remove(0); + } + writeBatchWrapper = new RocksDBWriteBatchWrapper(db, writeOptions); + // init snapshot strategy after db is assured to be initialized + initializeSnapshotStrategy(cancelStreamRegistry, rocksDBResourceGuard, + kvStateInformation, keyGroupPrefixBytes); + if (nativeMetricOptions.isEnabled()) { + nativeMetricMonitor = new RocksDBNativeMetricMonitor(db, nativeMetricOptions, metricGroup); + } + + backend = new RocksDBKeyedStateBackend<>( + this.operatorIdentifier, + this.userCodeClassLoader, + this.instanceBasePath, + this.dbOptions, + this.columnFamilyOptions, + this.kvStateRegistry, + this.keySerializer, + this.numberOfKeyGroups, + this.keyGroupRange, + this.executionConfig, + this.numberOfTransferingThreads, + this.ttlTimeProvider, + this.db, + kvStateInformation, + keyGroupPrefixBytes, + cancelStreamRegistry, + this.keyGroupCompressionDecorator, + rocksDBResourceGuard, + this.checkpointSnapshotStrategy, + this.savepointSnapshotStrategy, + writeBatchWrapper, + defaultColumnFamilyHandle, + nativeMetricMonitor); + PriorityQueueSetFactory priorityQueueFactory = initPriorityQueueFactory(backend); + backend.setPriorityQueueFactory(priorityQueueFactory); Review comment: This looks like a small code smell: we first need to create a backend, so that we can create the factory, so that we can set the factor in the backend. This also prevents that the factory can be assigned to a final field in the backend. I would suggest to refactor in the follwoing way: the `RocksDBPriorityQueueSetFactory` does actually not require the full backend object for construction, looks like this was more done for lazyness so that we don't need to pass all individual collaborators in the constructor. However, if we change the constructor of `RocksDBPriorityQueueSetFactory` to not require the full backend, but only the information and collaborators that it actually requires, we can create the factory befor creating the backend and also passing it into the backend constructor and can eliminate the setter. ---------------------------------------------------------------- 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. 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