akka.persistence.journal

Interface AsyncRecovery

All Known Subinterfaces:

AsyncWriteJournal, AsyncWriteProxy, LeveldbRecovery, LeveldbStore

All Known Implementing Classes:

AsyncRecovery, AsyncWriteJournal, InmemJournal, LeveldbJournal, SharedLeveldbJournal, SharedLeveldbStore

public interface AsyncRecovery

Asynchronous message replay and sequence number recovery interface.

Method Summary

Modifier and Type	Method and Description
scala.concurrent.Future<java.lang.Object>	asyncReadHighestSequenceNr(java.lang.String persistenceId, long fromSequenceNr) Plugin API: asynchronously reads the highest stored sequence number for the given persistenceId.
scala.concurrent.Future<scala.runtime.BoxedUnit>	asyncReplayMessages(java.lang.String persistenceId, long fromSequenceNr, long toSequenceNr, long max, scala.Function1<PersistentRepr,scala.runtime.BoxedUnit> recoveryCallback) Plugin API: asynchronously replays persistent messages.

Method Detail

asyncReplayMessages

scala.concurrent.Future<scala.runtime.BoxedUnit> asyncReplayMessages(java.lang.String persistenceId,
                                                                     long fromSequenceNr,
                                                                     long toSequenceNr,
                                                                     long max,
                                                                     scala.Function1<PersistentRepr,scala.runtime.BoxedUnit> recoveryCallback)

Plugin API: asynchronously replays persistent messages. Implementations replay a message by calling replayCallback. The returned future must be completed when all messages (matching the sequence number bounds) have been replayed. The future must be completed with a failure if any of the persistent messages could not be replayed.

The replayCallback must also be called with messages that have been marked as deleted. In this case a replayed message's deleted method must return true.

The toSequenceNr is the lowest of what was returned by asyncReadHighestSequenceNr(java.lang.String, long) and what the user specified as recovery Recovery parameter. This does imply that this call is always preceded by reading the highest sequence number for the given persistenceId.

This call is NOT protected with a circuit-breaker because it may take long time to replay all events. The plugin implementation itself must protect against an unresponsive backend store and make sure that the returned Future is completed with success or failure within reasonable time. It is not allowed to ignore completing the future.

Parameters:

persistenceId - persistent actor id.

fromSequenceNr - sequence number where replay should start (inclusive).

toSequenceNr - sequence number where replay should end (inclusive).

max - maximum number of messages to be replayed.

recoveryCallback - called to replay a single message. Can be called from any thread.

Returns:

(undocumented)

See Also:

AsyncWriteJournal

asyncReadHighestSequenceNr

scala.concurrent.Future<java.lang.Object> asyncReadHighestSequenceNr(java.lang.String persistenceId,
                                                                     long fromSequenceNr)

Plugin API: asynchronously reads the highest stored sequence number for the given persistenceId. The persistent actor will use the highest sequence number after recovery as the starting point when persisting new events. This sequence number is also used as toSequenceNr in subsequent call to asyncReplayMessages(java.lang.String, long, long, long, scala.Function1<akka.persistence.PersistentRepr, scala.runtime.BoxedUnit>) unless the user has specified a lower toSequenceNr. Journal must maintain the highest sequence number and never decrease it.

This call is protected with a circuit-breaker.

Please also note that requests for the highest sequence number may be made concurrently to writes executing for the same persistenceId, in particular it is possible that a restarting actor tries to recover before its outstanding writes have completed.

Parameters:

persistenceId - persistent actor id.

fromSequenceNr - hint where to start searching for the highest sequence number. When a persistent actor is recovering this fromSequenceNr will be the sequence number of the used snapshot or 0L if no snapshot is used.

Returns:

(undocumented)