Class IncrementalLocalKeyedStateHandle

    • Method Detail

      • discardState

        public void discardState()
                          throws Exception
        Description copied from interface: StateObject
        Discards the state referred to and solemnly owned by this handle, to free up resources in the persistent storage. This method is called when the state represented by this object will not be used anymore.
        Throws:
        Exception
      • getStateSize

        public long getStateSize()
        Description copied from interface: StateObject
        Returns the size of the state in bytes. If the size is not known, this method should return 0.

        The values produced by this method are only used for informational purposes and for metrics/monitoring. If this method returns wrong values, the checkpoints and recovery will still behave correctly. However, efficiency may be impacted (wrong space pre-allocation) and functionality that depends on metrics (like monitoring) will be impacted.

        Note for implementors: This method should not perform any I/O operations while obtaining the state size (hence it does not declare throwing an IOException). Instead, the state size should be stored in the state object, or should be computable from the state stored in this object. The reason is that this method is called frequently by several parts of the checkpointing and issuing I/O requests from this method accumulates a heavy I/O load on the storage system at higher scale.

        Returns:
        Size of the state in bytes.
      • collectSizeStats

        public void collectSizeStats​(StateObject.StateObjectSizeStatsCollector collector)
        Description copied from interface: StateObject
        Collects statistics about state size and location from the state object.
        Parameters:
        collector - the statistics collector.
      • registerSharedStates

        public void registerSharedStates​(SharedStateRegistry stateRegistry,
                                         long checkpointID)
        Description copied from interface: CompositeStateHandle
        Register both newly created and already referenced shared states in the given SharedStateRegistry. This method is called when the checkpoint successfully completes or is recovered from failures.

        After this is completed, newly created shared state is considered as published is no longer owned by this handle. This means that it should no longer be deleted as part of calls to StateObject.discardState(). Instead, StateObject.discardState() will trigger an unregistration from the registry.

        Parameters:
        stateRegistry - The registry where shared states are registered.
      • getCheckpointedSize

        public long getCheckpointedSize()
        Description copied from interface: CompositeStateHandle
        Returns the persisted data size during checkpoint execution in bytes. If incremental checkpoint is enabled, this value represents the incremental persisted data size, and usually smaller than StateObject.getStateSize(). If the size is unknown, this method would return same result as StateObject.getStateSize().
        Returns:
        The persisted data size during checkpoint execution in bytes.