public interface CompositeStateHandle extends StateObject
StateBackends and some other components in tasks.
Each snapshot is composed of a collection of
StateObjects some of which may be
referenced by other checkpoints. The shared states will be registered at the given
SharedStateRegistry when the handle is received by the
CheckpointCoordinator and will be discarded when the
checkpoint is discarded.
SharedStateRegistry is responsible for the discarding of registered shared states.
Before their first registration through
created shared state is still owned by this handle and considered as private state until it is
registered for the first time. Registration transfers ownership to the
SharedStateRegistry. The composite state handle should only delete all private states in the
StateObject.discardState() method, the
SharedStateRegistry is responsible for
deleting shared states after they were registered.
|Modifier and Type||Method and Description|
Register both newly created and already referenced shared states in the given
void registerSharedStates(SharedStateRegistry stateRegistry)
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
StateObject.discardState() will trigger an unregistration
from the registry.
stateRegistry- The registry where shared states are registered.
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