Package org.apache.flink.runtime.state

Interface AsyncKeyedStateBackend<K>

    • Method Summary

      All Methods Instance Methods Abstract Methods Default Methods 
      Modifier and Type Method Description
      StateExecutor createStateExecutor()
      Creates a StateExecutor which supports to execute a batch of state requests asynchronously.
      <N,​S extends InternalKeyedState,​SV>
      S      		 createStateInternal​(N defaultNamespace, org.apache.flink.api.common.typeutils.TypeSerializer<N> namespaceSerializer, org.apache.flink.api.common.state.v2.StateDescriptor<SV> stateDesc)
      Creates and returns a new state for internal usage.
      void dispose()  
      KeyGroupRange getKeyGroupRange()
      Returns the key groups which this state backend is responsible for.
      <N,​S extends org.apache.flink.api.common.state.v2.State,​SV>
      S      		 getOrCreateKeyedState​(N defaultNamespace, org.apache.flink.api.common.typeutils.TypeSerializer<N> namespaceSerializer, org.apache.flink.api.common.state.v2.StateDescriptor<SV> stateDesc)
      Creates or retrieves a keyed state backed by this state backend.
      default boolean isSafeToReuseKVState()
      Whether it's safe to reuse key-values from the state-backend, e.g for the purpose of optimization.
      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 org.apache.flink.api.common.state.InternalCheckpointListener

        notifyCheckpointSubsumed

    • Method Detail

      • setup

        void setup​(@Nonnull
           StateRequestHandler stateRequestHandler)
        Initializes with some contexts.
        Parameters:
        stateRequestHandler - which handles state request.

      • getOrCreateKeyedState

        <N,​S extends org.apache.flink.api.common.state.v2.State,​SV> S getOrCreateKeyedState​(N defaultNamespace,
                                                                                                org.apache.flink.api.common.typeutils.TypeSerializer<N> namespaceSerializer,
                                                                                                org.apache.flink.api.common.state.v2.StateDescriptor<SV> stateDesc)
                                                                                         throws Exception
        Creates or retrieves a keyed state backed by this state backend.
        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.
        Returns:
        A new key/value state backed by this backend.
        Throws:
        Exception - Exceptions may occur during initialization of the state and should be forwarded.

      • createStateInternal

        @Nonnull
<N,​S extends InternalKeyedState,​SV> S createStateInternal​(@Nonnull
                                                                      N defaultNamespace,
                                                                      @Nonnull
                                                                      org.apache.flink.api.common.typeutils.TypeSerializer<N> namespaceSerializer,
                                                                      @Nonnull
                                                                      org.apache.flink.api.common.state.v2.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.

      • 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

      • isSafeToReuseKVState

        default boolean isSafeToReuseKVState()
        Whether it's safe to reuse key-values from the state-backend, e.g for the purpose of optimization.

        NOTE: this method should not be used to check for InternalPriorityQueue, as the priority queue could be stored on different locations, e.g ForSt state-backend could store that on JVM heap if configuring HEAP as the time-service factory.

        Returns:
        returns ture if safe to reuse the key-values from the state-backend.

      • dispose

        void dispose()
        Specified by:
        dispose in interface org.apache.flink.util.Disposable