org.apache.flink.changelog.fs

Interface TaskChangelogRegistry

@Internal
public interface TaskChangelogRegistry

TM-side registry of StateObjects, each representing one or more changelog segments. Changelog segments are uploaded by StateChangelogWriters of a StateChangelogStorage.

Initially, when starting the tracking, the ownership of a changelog segments is not clear, and it is assumed that JM might be the owner. Once the backends are not using the segments, JM can not become an owner anymore. the state is discarded.

However, if at any point it becomes known that JM is the owner, tracking is stopped and the state will not be discarded.

It is the client responsibility to make sure that JM can not become an owner when calling notUsed(StreamStateHandle, UUID).

Field Summary

Fields

Modifier and Type	Field and Description
static TaskChangelogRegistry	NO_OP

Method Summary

Modifier and Type	Method and Description
static TaskChangelogRegistry	defaultChangelogRegistry(Executor executor)
static TaskChangelogRegistry	defaultChangelogRegistry(int numAsyncDiscardThreads)
void	notUsed(StreamStateHandle handle, UUID backendId) Mark the state as unused by the given backend, e.g.
void	startTracking(StreamStateHandle handle, Set<UUID> backendIDs) Start tracking the state uploaded for the given backends.
void	stopTracking(StreamStateHandle handle) Stop tracking the state, so that it's not tracked (some other component is doing that).

Field Detail

NO_OP

static final TaskChangelogRegistry NO_OP

Method Detail

startTracking

void startTracking(StreamStateHandle handle,
                   Set<UUID> backendIDs)

Start tracking the state uploaded for the given backends.

stopTracking

void stopTracking(StreamStateHandle handle)

Stop tracking the state, so that it's not tracked (some other component is doing that).

notUsed

void notUsed(StreamStateHandle handle,
             UUID backendId)

Mark the state as unused by the given backend, e.g. if it was pre-emptively uploaded and materialized. Once no backend is using the state, it is discarded (unless it was unregistered earlier).

defaultChangelogRegistry

static TaskChangelogRegistry defaultChangelogRegistry(int numAsyncDiscardThreads)

defaultChangelogRegistry

@VisibleForTesting
static TaskChangelogRegistry defaultChangelogRegistry(Executor executor)