org.apache.flink.runtime.state.changelog.inmemory

Class InMemoryChangelogStateHandle

java.lang.Object

org.apache.flink.runtime.state.changelog.inmemory.InMemoryChangelogStateHandle

All Implemented Interfaces:

Serializable, ChangelogStateHandle, CompositeStateHandle, KeyedStateHandle, StateObject

@Internal
public class InMemoryChangelogStateHandle
extends Object
implements ChangelogStateHandle

In-memory ChangelogStateHandle.

See Also:

Serialized Form

Nested Class Summary

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

StateObject.StateObjectLocation, StateObject.StateObjectSizeStatsCollector

Constructor Summary

Constructors

Constructor and Description
InMemoryChangelogStateHandle(List<StateChange> changes, SequenceNumber from, SequenceNumber to, KeyGroupRange keyGroupRange)

Method Summary

Modifier and Type	Method and Description
void	collectSizeStats(StateObject.StateObjectSizeStatsCollector collector) Collects statistics about state size and location from the state object.
void	discardState() Discards the state referred to and solemnly owned by this handle, to free up resources in the persistent storage.
List<StateChange>	getChanges()
long	getCheckpointedSize() Returns the persisted data size during checkpoint execution in bytes.
long	getFrom()
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.
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.
String	getStorageIdentifier() Get the storage identifier related to a specific StateChangelogStorage.
long	getTo()
void	registerSharedStates(SharedStateRegistry stateRegistry, long checkpointID) Register both newly created and already referenced shared states in the given SharedStateRegistry.
static InMemoryChangelogStateHandle	restore(List<StateChange> changes, SequenceNumber from, SequenceNumber to, KeyGroupRange keyGroupRange, StateHandleID stateHandleId)
String	toString()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

InMemoryChangelogStateHandle

public InMemoryChangelogStateHandle(List<StateChange> changes,
                                    SequenceNumber from,
                                    SequenceNumber to,
                                    KeyGroupRange keyGroupRange)

Method Detail

restore

public static InMemoryChangelogStateHandle restore(List<StateChange> changes,
                                                   SequenceNumber from,
                                                   SequenceNumber to,
                                                   KeyGroupRange keyGroupRange,
                                                   StateHandleID stateHandleId)

discardState

public void discardState()

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.

Specified by:

discardState in interface StateObject

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.

collectSizeStats

public void collectSizeStats(StateObject.StateObjectSizeStatsCollector collector)

Description copied from interface: StateObject

Collects statistics about state size and location from the state object.

Specified by:

collectSizeStats in interface StateObject

Parameters:

collector - the statistics collector.

getChanges

public List<StateChange> getChanges()

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

getIntersection

@Nullable
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.

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.

toString

public String toString()

Overrides:

toString in class Object

getFrom

public long getFrom()

getTo

public long getTo()

getStorageIdentifier

public String getStorageIdentifier()

Description copied from interface: ChangelogStateHandle

Get the storage identifier related to a specific StateChangelogStorage.

Specified by:

getStorageIdentifier in interface ChangelogStateHandle