org.apache.flink.runtime.state

Interface CompositeStateHandle

All Superinterfaces:

Serializable, StateObject

All Known Subinterfaces:

KeyedStateHandle

All Known Implementing Classes:

DirectoryKeyedStateHandle, IncrementalKeyedStateHandle, IncrementalLocalKeyedStateHandle, KeyGroupsStateHandle, OperatorState, OperatorSubtaskState, SubtaskState, TaskState, TaskStateSnapshot

public interface CompositeStateHandle
extends StateObject

Base of all snapshots that are taken by 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.

The SharedStateRegistry is responsible for the discarding of registered shared states. Before their first registration through registerSharedStates(SharedStateRegistry), newly 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.

Method Summary

Modifier and Type	Method and Description
void	registerSharedStates(SharedStateRegistry stateRegistry) Register both newly created and already referenced shared states in the given SharedStateRegistry.

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

discardState, getStateSize

Method Detail

registerSharedStates

void registerSharedStates(SharedStateRegistry stateRegistry)

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.