org.apache.flink.runtime.state

Class IncrementalRemoteKeyedStateHandle

java.lang.Object

org.apache.flink.runtime.state.IncrementalRemoteKeyedStateHandle

All Implemented Interfaces:

Serializable, CheckpointBoundKeyedStateHandle, CompositeStateHandle, IncrementalKeyedStateHandle, KeyedStateHandle, StateObject

public class IncrementalRemoteKeyedStateHandle
extends Object
implements IncrementalKeyedStateHandle

The handle to states of an incremental snapshot.

The states contained in an incremental snapshot include:

• Created shared state which includes shared files produced since the last completed checkpoint. These files can be referenced by succeeding checkpoints if the checkpoint succeeds to complete.
• Referenced shared state which includes the shared files materialized in previous checkpoints. Until we this is registered to a SharedStateRegistry, all referenced shared state handles are only placeholders, so that we do not send state handles twice from which we know that they already exist on the checkpoint coordinator.
• Private state which includes all other files, typically mutable, that cannot be shared by other checkpoints.
• Backend meta state which includes the information of existing states.

When this should become a completed checkpoint on the checkpoint coordinator, it must first be registered with a SharedStateRegistry, so that all placeholder state handles to previously existing state are replaced with the originals.

IMPORTANT: This class currently overrides equals and hash code only for testing purposes. They should not be called from production code. This means this class is also not suited to serve as a key, e.g. in hash maps.

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from interface org.apache.flink.runtime.state.IncrementalKeyedStateHandle

IncrementalKeyedStateHandle.HandleAndLocalPath

Field Summary

Fields

Modifier and Type	Field and Description
static long	UNKNOWN_CHECKPOINTED_SIZE

Constructor Summary

Constructors

Modifier	Constructor and Description
	IncrementalRemoteKeyedStateHandle(UUID backendIdentifier, KeyGroupRange keyGroupRange, long checkpointId, List<IncrementalKeyedStateHandle.HandleAndLocalPath> sharedState, List<IncrementalKeyedStateHandle.HandleAndLocalPath> privateState, StreamStateHandle metaStateHandle)
	IncrementalRemoteKeyedStateHandle(UUID backendIdentifier, KeyGroupRange keyGroupRange, long checkpointId, List<IncrementalKeyedStateHandle.HandleAndLocalPath> sharedState, List<IncrementalKeyedStateHandle.HandleAndLocalPath> privateState, StreamStateHandle metaStateHandle, long persistedSizeOfThisCheckpoint)
protected	IncrementalRemoteKeyedStateHandle(UUID backendIdentifier, KeyGroupRange keyGroupRange, long checkpointId, List<IncrementalKeyedStateHandle.HandleAndLocalPath> sharedState, List<IncrementalKeyedStateHandle.HandleAndLocalPath> privateState, StreamStateHandle metaStateHandle, long persistedSizeOfThisCheckpoint, StateHandleID stateHandleId)

Method Summary

Modifier and Type	Method and Description
SharedStateRegistryKey	createSharedStateRegistryKey(StreamStateHandle handle) Create a unique key based on physical id to register one of our shared state handles.
void	discardState() Discards the state referred to and solemnly owned by this handle, to free up resources in the persistent storage.
boolean	equals(Object o) This method is should only be called in tests! This should never serve as key in a hash map.
UUID	getBackendIdentifier() Returns the identifier of the state backend from which this handle was created.
long	getCheckpointedSize() Returns the persisted data size during checkpoint execution in bytes.
long	getCheckpointId() Returns the ID of the checkpoint for which the handle was created or used.
KeyedStateHandle	getIntersection(KeyGroupRange keyGroupRange) Returns a state over a range that is the intersection between this handle's key-group range and the provided key-group range.
KeyGroupRange	getKeyGroupRange() Returns the range of the key groups contained in the state.
StreamStateHandle	getMetaStateHandle()
List<IncrementalKeyedStateHandle.HandleAndLocalPath>	getPrivateState()
List<IncrementalKeyedStateHandle.HandleAndLocalPath>	getSharedState()
List<IncrementalKeyedStateHandle.HandleAndLocalPath>	getSharedStateHandles() Returns a list of all shared states and the corresponding localPath in the backend at the time this was created.
SharedStateRegistry	getSharedStateRegistry()
StateHandleID	getStateHandleId() Returns a unique state handle id to distinguish with other keyed state handles.
long	getStateSize() Returns the size of the state in bytes.
int	hashCode() This method should only be called in tests! This should never serve as key in a hash map.
CheckpointBoundKeyedStateHandle	rebound(long checkpointId) Returns a new CheckpointBoundKeyedStateHandle Rebounding checkpoint id to a specific checkpoint id.
void	registerSharedStates(SharedStateRegistry stateRegistry, long checkpointID) Register both newly created and already referenced shared states in the given SharedStateRegistry.
static IncrementalRemoteKeyedStateHandle	restore(UUID backendIdentifier, KeyGroupRange keyGroupRange, long checkpointId, List<IncrementalKeyedStateHandle.HandleAndLocalPath> sharedState, List<IncrementalKeyedStateHandle.HandleAndLocalPath> privateState, StreamStateHandle metaStateHandle, long persistedSizeOfThisCheckpoint, StateHandleID stateHandleId)
String	toString()

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

UNKNOWN_CHECKPOINTED_SIZE

public static final long UNKNOWN_CHECKPOINTED_SIZE

See Also:

Constant Field Values

Constructor Detail

IncrementalRemoteKeyedStateHandle

@VisibleForTesting
public IncrementalRemoteKeyedStateHandle(UUID backendIdentifier,
                                                            KeyGroupRange keyGroupRange,
                                                            long checkpointId,
                                                            List<IncrementalKeyedStateHandle.HandleAndLocalPath> sharedState,
                                                            List<IncrementalKeyedStateHandle.HandleAndLocalPath> privateState,
                                                            StreamStateHandle metaStateHandle)

IncrementalRemoteKeyedStateHandle

public IncrementalRemoteKeyedStateHandle(UUID backendIdentifier,
                                         KeyGroupRange keyGroupRange,
                                         long checkpointId,
                                         List<IncrementalKeyedStateHandle.HandleAndLocalPath> sharedState,
                                         List<IncrementalKeyedStateHandle.HandleAndLocalPath> privateState,
                                         StreamStateHandle metaStateHandle,
                                         long persistedSizeOfThisCheckpoint)

IncrementalRemoteKeyedStateHandle

protected IncrementalRemoteKeyedStateHandle(UUID backendIdentifier,
                                            KeyGroupRange keyGroupRange,
                                            long checkpointId,
                                            List<IncrementalKeyedStateHandle.HandleAndLocalPath> sharedState,
                                            List<IncrementalKeyedStateHandle.HandleAndLocalPath> privateState,
                                            StreamStateHandle metaStateHandle,
                                            long persistedSizeOfThisCheckpoint,
                                            StateHandleID stateHandleId)

Method Detail

restore

public static IncrementalRemoteKeyedStateHandle restore(UUID backendIdentifier,
                                                        KeyGroupRange keyGroupRange,
                                                        long checkpointId,
                                                        List<IncrementalKeyedStateHandle.HandleAndLocalPath> sharedState,
                                                        List<IncrementalKeyedStateHandle.HandleAndLocalPath> privateState,
                                                        StreamStateHandle metaStateHandle,
                                                        long persistedSizeOfThisCheckpoint,
                                                        StateHandleID stateHandleId)

getKeyGroupRange

public KeyGroupRange getKeyGroupRange()

Description copied from interface: KeyedStateHandle

Returns the range of the key groups contained in the state.

Specified by:

getKeyGroupRange in interface KeyedStateHandle

getCheckpointId

public long getCheckpointId()

Description copied from interface: CheckpointBoundKeyedStateHandle

Returns the ID of the checkpoint for which the handle was created or used.

Specified by:

getCheckpointId in interface CheckpointBoundKeyedStateHandle

rebound

public CheckpointBoundKeyedStateHandle rebound(long checkpointId)

Description copied from interface: CheckpointBoundKeyedStateHandle

Returns a new CheckpointBoundKeyedStateHandle Rebounding checkpoint id to a specific checkpoint id.

Specified by:

rebound in interface CheckpointBoundKeyedStateHandle

Parameters:

checkpointId - rebounded checkpoint id.

getSharedState

public List<IncrementalKeyedStateHandle.HandleAndLocalPath> getSharedState()

getPrivateState

public List<IncrementalKeyedStateHandle.HandleAndLocalPath> getPrivateState()

getMetaStateHandle

public StreamStateHandle getMetaStateHandle()

getBackendIdentifier

@Nonnull
public UUID getBackendIdentifier()

Description copied from interface: IncrementalKeyedStateHandle

Returns the identifier of the state backend from which this handle was created.

Specified by:

getBackendIdentifier in interface IncrementalKeyedStateHandle

getSharedStateHandles

@Nonnull
public List<IncrementalKeyedStateHandle.HandleAndLocalPath> getSharedStateHandles()

Description copied from interface: IncrementalKeyedStateHandle

Returns a list of all shared states and the corresponding localPath in the backend at the time this was created.

Specified by:

getSharedStateHandles in interface IncrementalKeyedStateHandle

getSharedStateRegistry

public SharedStateRegistry getSharedStateRegistry()

getIntersection

public KeyedStateHandle getIntersection(KeyGroupRange keyGroupRange)

Description copied from interface: KeyedStateHandle

Returns a state over a range that is the intersection between this handle's key-group range and the provided key-group range.

Specified by:

getIntersection in interface KeyedStateHandle

Parameters:

keyGroupRange - The key group range to intersect with, will return null if the intersection of this handle's key-group and the provided key-group is empty.

getStateHandleId

public StateHandleID getStateHandleId()

Description copied from interface: KeyedStateHandle

Returns a unique state handle id to distinguish with other keyed state handles.

If this state handle would be used as materialized part of ChangelogStateBackendHandle, it should persist this state handle id when serializing of checkpoint and deserialize it back to ensure the state handle id is constant.

Specified by:

getStateHandleId in interface KeyedStateHandle

Returns:

A unique state handle id.

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 any more.

Specified by:

discardState in interface StateObject

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.

Specified by:

getStateSize in interface StateObject

Returns:

Size of the state in bytes.

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().

Specified by:

getCheckpointedSize in interface CompositeStateHandle

Returns:

The persisted data size during checkpoint execution in bytes.

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.

Specified by:

registerSharedStates in interface CompositeStateHandle

Parameters:

stateRegistry - The registry where shared states are registered.

createSharedStateRegistryKey

@VisibleForTesting
public SharedStateRegistryKey createSharedStateRegistryKey(StreamStateHandle handle)

Create a unique key based on physical id to register one of our shared state handles.

equals

@VisibleForTesting
public boolean equals(Object o)

This method is should only be called in tests! This should never serve as key in a hash map.

Overrides:

equals in class Object

hashCode

@VisibleForTesting
public int hashCode()

This method should only be called in tests! This should never serve as key in a hash map.

Overrides:

hashCode in class Object

toString

public String toString()

Overrides:

toString in class Object