org.apache.flink.contrib.streaming.state

Class RocksDBKeyedStateBackend<K>

java.lang.Object

org.apache.flink.runtime.state.AbstractKeyedStateBackend<K>

org.apache.flink.contrib.streaming.state.RocksDBKeyedStateBackend<K>

All Implemented Interfaces:

Closeable, AutoCloseable, org.apache.flink.runtime.state.CheckpointListener, org.apache.flink.runtime.state.heap.InternalKeyContext<K>, org.apache.flink.runtime.state.KeyedStateBackend<K>, org.apache.flink.runtime.state.KeyedStateFactory, org.apache.flink.runtime.state.PriorityQueueSetFactory, org.apache.flink.runtime.state.Snapshotable<org.apache.flink.runtime.state.SnapshotResult<org.apache.flink.runtime.state.KeyedStateHandle>,Collection<org.apache.flink.runtime.state.KeyedStateHandle>>, org.apache.flink.util.Disposable

public class RocksDBKeyedStateBackend<K>
extends org.apache.flink.runtime.state.AbstractKeyedStateBackend<K>

An AbstractKeyedStateBackend that stores its state in RocksDB and serializes state to streams provided by a CheckpointStreamFactory upon checkpointing. This state backend can store very large state that exceeds memory and spills to disk. Except for the snapshotting, this class should be accessed as if it is not threadsafe.

This class follows the rules for closing/releasing native RocksDB resources as described in + this document.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
protected static class	RocksDBKeyedStateBackend.MergeIterator Wraps a RocksDB iterator to cache it's current key and assigns an id for the key/value state to the iterator.

Field Summary

Fields

Modifier and Type	Field and Description
protected org.rocksdb.RocksDB	db Our RocksDB database, this is used by the actual subclasses of AbstractRocksDBState to store state.
static String	MERGE_OPERATOR_NAME The name of the merge operator in RocksDB.

Fields inherited from class org.apache.flink.runtime.state.AbstractKeyedStateBackend

cancelStreamRegistry, keyGroupCompressionDecorator, keyGroupRange, keySerializer, kvStateRegistry, numberOfKeyGroups, userCodeClassLoader

Constructor Summary

Constructors

Constructor and Description

RocksDBKeyedStateBackend(String operatorIdentifier, ClassLoader userCodeClassLoader, File instanceBasePath, org.rocksdb.DBOptions dbOptions, org.rocksdb.ColumnFamilyOptions columnFamilyOptions, org.apache.flink.runtime.query.TaskKvStateRegistry kvStateRegistry, org.apache.flink.api.common.typeutils.TypeSerializer<K> keySerializer, int numberOfKeyGroups, org.apache.flink.runtime.state.KeyGroupRange keyGroupRange, org.apache.flink.api.common.ExecutionConfig executionConfig, boolean enableIncrementalCheckpointing, org.apache.flink.runtime.state.LocalRecoveryConfig localRecoveryConfig, RocksDBStateBackend.PriorityQueueStateType priorityQueueStateType, org.apache.flink.runtime.state.ttl.TtlTimeProvider ttlTimeProvider)

Method Summary

Modifier and Type	Method and Description
<T extends org.apache.flink.runtime.state.heap.HeapPriorityQueueElement & org.apache.flink.runtime.state.PriorityComparable & org.apache.flink.runtime.state.Keyed> org.apache.flink.runtime.state.KeyGroupedInternalPriorityQueue<T>	create(String stateName, org.apache.flink.api.common.typeutils.TypeSerializer<T> byteOrderedElementSerializer)
<N,SV,SEV,S extends org.apache.flink.api.common.state.State,IS extends S> IS	createInternalState(org.apache.flink.api.common.typeutils.TypeSerializer<N> namespaceSerializer, org.apache.flink.api.common.state.StateDescriptor<S,SV> stateDesc, org.apache.flink.runtime.state.StateSnapshotTransformer.StateSnapshotTransformFactory<SEV> snapshotTransformFactory)
void	dispose() Should only be called by one thread, and only after all accesses to the DB happened.
File	getInstanceBasePath() Only visible for testing, DO NOT USE.
int	getKeyGroupPrefixBytes()
<N> java.util.stream.Stream<K>	getKeys(String state, N namespace)
static RocksIteratorWrapper	getRocksIterator(org.rocksdb.RocksDB db)
static RocksIteratorWrapper	getRocksIterator(org.rocksdb.RocksDB db, org.rocksdb.ColumnFamilyHandle columnFamilyHandle)
org.rocksdb.WriteOptions	getWriteOptions()
void	notifyCheckpointComplete(long completedCheckpointId)
int	numKeyValueStateEntries()
boolean	requiresLegacySynchronousTimerSnapshots()
void	restore(Collection<org.apache.flink.runtime.state.KeyedStateHandle> restoreState)
RunnableFuture<org.apache.flink.runtime.state.SnapshotResult<org.apache.flink.runtime.state.KeyedStateHandle>>	snapshot(long checkpointId, long timestamp, org.apache.flink.runtime.state.CheckpointStreamFactory streamFactory, org.apache.flink.runtime.checkpoint.CheckpointOptions checkpointOptions) Triggers an asynchronous snapshot of the keyed state backend from RocksDB.
boolean	supportsAsynchronousSnapshots()

Methods inherited from class org.apache.flink.runtime.state.AbstractKeyedStateBackend

applyToAllKeys, close, getCurrentKey, getCurrentKeyGroupIndex, getKeyGroupRange, getKeySerializer, getNumberOfKeyGroups, getOrCreateKeyedState, getPartitionedState, setCurrentKey

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface org.apache.flink.runtime.state.KeyedStateFactory

createInternalState

Field Detail

MERGE_OPERATOR_NAME

public static final String MERGE_OPERATOR_NAME

The name of the merge operator in RocksDB. Do not change except you know exactly what you do.

See Also:

Constant Field Values

db

protected org.rocksdb.RocksDB db

Our RocksDB database, this is used by the actual subclasses of AbstractRocksDBState to store state. The different k/v states that we have don't each have their own RocksDB instance. They all write to this instance but to their own column family.

Constructor Detail

RocksDBKeyedStateBackend

public RocksDBKeyedStateBackend(String operatorIdentifier,
                                ClassLoader userCodeClassLoader,
                                File instanceBasePath,
                                org.rocksdb.DBOptions dbOptions,
                                org.rocksdb.ColumnFamilyOptions columnFamilyOptions,
                                org.apache.flink.runtime.query.TaskKvStateRegistry kvStateRegistry,
                                org.apache.flink.api.common.typeutils.TypeSerializer<K> keySerializer,
                                int numberOfKeyGroups,
                                org.apache.flink.runtime.state.KeyGroupRange keyGroupRange,
                                org.apache.flink.api.common.ExecutionConfig executionConfig,
                                boolean enableIncrementalCheckpointing,
                                org.apache.flink.runtime.state.LocalRecoveryConfig localRecoveryConfig,
                                RocksDBStateBackend.PriorityQueueStateType priorityQueueStateType,
                                org.apache.flink.runtime.state.ttl.TtlTimeProvider ttlTimeProvider)
                         throws IOException

Throws:

IOException

Method Detail

getKeys

public <N> java.util.stream.Stream<K> getKeys(String state,
                                              N namespace)

dispose

public void dispose()

Should only be called by one thread, and only after all accesses to the DB happened.

Specified by:

dispose in interface org.apache.flink.runtime.state.KeyedStateBackend<K>

Specified by:

dispose in interface org.apache.flink.util.Disposable

Overrides:

dispose in class org.apache.flink.runtime.state.AbstractKeyedStateBackend<K>

create

@Nonnull
public <T extends org.apache.flink.runtime.state.heap.HeapPriorityQueueElement & org.apache.flink.runtime.state.PriorityComparable & org.apache.flink.runtime.state.Keyed> org.apache.flink.runtime.state.KeyGroupedInternalPriorityQueue<T> create(@Nonnull
                                                                                                                                                                                                                                                             String stateName,
                                                                                                                                                                                                                                                             @Nonnull
                                                                                                                                                                                                                                                             org.apache.flink.api.common.typeutils.TypeSerializer<T> byteOrderedElementSerializer)

getKeyGroupPrefixBytes

public int getKeyGroupPrefixBytes()

getWriteOptions

public org.rocksdb.WriteOptions getWriteOptions()

snapshot

public RunnableFuture<org.apache.flink.runtime.state.SnapshotResult<org.apache.flink.runtime.state.KeyedStateHandle>> snapshot(long checkpointId,
                                                                                                                               long timestamp,
                                                                                                                               org.apache.flink.runtime.state.CheckpointStreamFactory streamFactory,
                                                                                                                               org.apache.flink.runtime.checkpoint.CheckpointOptions checkpointOptions)
                                                                                                                        throws Exception

Triggers an asynchronous snapshot of the keyed state backend from RocksDB. This snapshot can be canceled and is also stopped when the backend is closed through dispose(). For each backend, this method must always be called by the same thread.

Parameters:

checkpointId - The Id of the checkpoint.

timestamp - The timestamp of the checkpoint.

streamFactory - The factory that we can use for writing our state to streams.

checkpointOptions - Options for how to perform this checkpoint.

Returns:

Future to the state handle of the snapshot data.

Throws:

Exception - indicating a problem in the synchronous part of the checkpoint.

restore

public void restore(Collection<org.apache.flink.runtime.state.KeyedStateHandle> restoreState)
             throws Exception

Throws:

Exception

notifyCheckpointComplete

public void notifyCheckpointComplete(long completedCheckpointId)

createInternalState

@Nonnull
public <N,SV,SEV,S extends org.apache.flink.api.common.state.State,IS extends S> IS createInternalState(@Nonnull
                                                                                                                 org.apache.flink.api.common.typeutils.TypeSerializer<N> namespaceSerializer,
                                                                                                                 @Nonnull
                                                                                                                 org.apache.flink.api.common.state.StateDescriptor<S,SV> stateDesc,
                                                                                                                 @Nonnull
                                                                                                                 org.apache.flink.runtime.state.StateSnapshotTransformer.StateSnapshotTransformFactory<SEV> snapshotTransformFactory)
                                                                                                          throws Exception

Throws:

Exception

getInstanceBasePath

public File getInstanceBasePath()

Only visible for testing, DO NOT USE.

supportsAsynchronousSnapshots

public boolean supportsAsynchronousSnapshots()

Overrides:

supportsAsynchronousSnapshots in class org.apache.flink.runtime.state.AbstractKeyedStateBackend<K>

numKeyValueStateEntries

@VisibleForTesting
public int numKeyValueStateEntries()

Specified by:

numKeyValueStateEntries in class org.apache.flink.runtime.state.AbstractKeyedStateBackend<K>

getRocksIterator

public static RocksIteratorWrapper getRocksIterator(org.rocksdb.RocksDB db)

getRocksIterator

public static RocksIteratorWrapper getRocksIterator(org.rocksdb.RocksDB db,
                                                    org.rocksdb.ColumnFamilyHandle columnFamilyHandle)

requiresLegacySynchronousTimerSnapshots

public boolean requiresLegacySynchronousTimerSnapshots()

Overrides:

requiresLegacySynchronousTimerSnapshots in class org.apache.flink.runtime.state.AbstractKeyedStateBackend<K>