Package org.apache.flink.runtime.state

Interface AsyncKeyedStateBackend<K>

All Superinterfaces:

AsyncExecutionController.SwitchContextListener<K>, AutoCloseable, CheckpointListener, Closeable, Disposable, InternalCheckpointListener, PriorityQueueSetFactory, Snapshotable<SnapshotResult<KeyedStateHandle>>

All Known Implementing Classes:

AsyncKeyedStateBackendAdaptor, ForStKeyedStateBackend

@Internal
public interface AsyncKeyedStateBackend<K>
extends Snapshotable<SnapshotResult<KeyedStateHandle>>, InternalCheckpointListener, PriorityQueueSetFactory, Disposable, Closeable, AsyncExecutionController.SwitchContextListener<K>

An async keyed state backend provides methods supporting to access keyed state asynchronously and in batch.

Method Summary

Modifier and Type	Method	Description
<N,S extends State,SV> S	createState(N defaultNamespace, TypeSerializer<N> namespaceSerializer, StateDescriptor<SV> stateDesc)	Creates and returns a new state.
StateExecutor	createStateExecutor()	Creates a StateExecutor which supports to execute a batch of state requests asynchronously.
<N,S extends InternalKeyedState,SV> S	createStateInternal(N defaultNamespace, TypeSerializer<N> namespaceSerializer, StateDescriptor<SV> stateDesc)	Creates and returns a new state for internal usage.
void	dispose()	Disposes the object and releases all resources.
KeyGroupRange	getKeyGroupRange()	Returns the key groups which this state backend is responsible for.
default boolean	requiresLegacySynchronousTimerSnapshots(SnapshotType checkpointType)	Whether the keyed state backend requires legacy synchronous timer snapshots.
void	setup(StateRequestHandler stateRequestHandler)	Initializes with some contexts.
default void	switchContext(RecordContext<K> context)	By default, a state backend does nothing when a key is switched in async processing.

Methods inherited from interface org.apache.flink.api.common.state.CheckpointListener

notifyCheckpointAborted, notifyCheckpointComplete

Methods inherited from interface java.io.Closeable

close

Methods inherited from interface org.apache.flink.api.common.state.InternalCheckpointListener

notifyCheckpointSubsumed

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

create, create

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

snapshot

Method Detail

setup

void setup(@Nonnull
           StateRequestHandler stateRequestHandler)

Initializes with some contexts.

Parameters:

stateRequestHandler - which handles state request.

createState

@Nonnull
<N,S extends State,SV> S createState(@Nonnull
                                                 N defaultNamespace,
                                                 @Nonnull
                                                 TypeSerializer<N> namespaceSerializer,
                                                 @Nonnull
                                                 StateDescriptor<SV> stateDesc)
                                          throws Exception

Creates and returns a new state.

Type Parameters:

N - the type of namespace for partitioning.

S - The type of the public API state.

SV - The type of the stored state value.

Parameters:

defaultNamespace - the default namespace for this state.

namespaceSerializer - the serializer for namespace.

stateDesc - The StateDescriptor that contains the name of the state.

Throws:

Exception - Exceptions may occur during initialization of the state.

createStateInternal

@Nonnull
<N,S extends InternalKeyedState,SV> S createStateInternal(@Nonnull
                                                                      N defaultNamespace,
                                                                      @Nonnull
                                                                      TypeSerializer<N> namespaceSerializer,
                                                                      @Nonnull
                                                                      StateDescriptor<SV> stateDesc)
                                                               throws Exception

Creates and returns a new state for internal usage.

Type Parameters:

N - the type of namespace for partitioning.

S - The type of the public API state.

SV - The type of the stored state value.

Parameters:

defaultNamespace - the default namespace for this state.

namespaceSerializer - the serializer for namespace.

stateDesc - The StateDescriptor that contains the name of the state.

Throws:

Exception - Exceptions may occur during initialization of the state.

createStateExecutor

@Nonnull
StateExecutor createStateExecutor()

Creates a StateExecutor which supports to execute a batch of state requests asynchronously.

Notice that the AsyncKeyedStateBackend is responsible for shutting down the StateExecutors created by itself when they are no longer in use.

Returns:

a StateExecutor which supports to execute a batch of state requests asynchronously.

getKeyGroupRange

KeyGroupRange getKeyGroupRange()

Returns the key groups which this state backend is responsible for.

switchContext

default void switchContext(RecordContext<K> context)

By default, a state backend does nothing when a key is switched in async processing.

Specified by:

switchContext in interface AsyncExecutionController.SwitchContextListener<K>

requiresLegacySynchronousTimerSnapshots

default boolean requiresLegacySynchronousTimerSnapshots(SnapshotType checkpointType)

Whether the keyed state backend requires legacy synchronous timer snapshots.

Parameters:

checkpointType -

Returns:

true as default in case of AsyncKeyedStateBackend

dispose

void dispose()

Description copied from interface: Disposable

Disposes the object and releases all resources. After calling this method, calling any methods on the object may result in undefined behavior.

Specified by:

dispose in interface Disposable