Hi Not sure if this is still a problem for you. Faced with a similar type of problem I create persistent actors per "job" and have a master which keeps the state of all. This means that on recover, I quickly can see which of my jobs were completed and which not. So my "master" would have a structure something like
case clas Job(jobId, status) var jobs = Set[Job] Events on master would be job started, job completed, job deleted. When recovering jobs you then restart the actors for the jobs that were not completed. The persistent job actor would just maintain the individual job state and there would be another actor to actually run the job. When you want to get rid of it you can delete the entire journal for that job and have the master know that it's been deleted. So master is technically unbounded but it's also small, so you probably wouldn't need to do much to keep size under control. You might also find it's worth keeping permanently if your status included information about the success or failure of jobs (rather depends on what the jobs are). However it's also easy to control its load time snapshot etc. On Friday, November 27, 2015 at 11:42:14 PM UTC, Harit Himanshu wrote: > > Hello there, > > I am working on akka-persistence and my use case looks like following > > > - Jobs are submitted to PersistentActor, which are then journaled to > leveldb. I also maintain a state variable (as shown in the akka docs > <http://doc.akka.io/docs/akka/snapshot/scala/persistence.html>) > - There are worker actors who work on these jobs. > - Once worker completes the job successfully, I would like to remove > the job from leveldb and update the state variable. > > > I looked at the message deletion > <http://doc.akka.io/docs/akka/snapshot/scala/persistence.html#Message_deletion> > > section, which has deleteMessages(toSequenceNr) API, but my confusion is > that I do not know the toSequenceNr. Infact, there may be many workers > working on different jobs at any time, and I want to remove a specific job > which is completed successfully. > > Once the message is deleted, I am ideally making this journal bounded > (otherwise it will increases forever). In this case, snapshots will be > smaller as well. > > How can I achieve this use case? Or am I not doing things right? > > My current code looks like > > import akka.actor.{Props, ActorSystem, ActorLogging} > import akka.event.LoggingReceive > import akka.persistence.{SaveSnapshotFailure, SaveSnapshotSuccess, > SnapshotOffer, PersistentActor} > > case class Command(data: String) > > case class Event(data: String) > > case object InternalState > > case object TakeSnapshot > > case object ShutDown > case object Fail > > case class State(queue: List[String] = Nil) { > def updated(event: Event): State = copy(event.data :: queue) > > def size: Int = queue.length > > override def toString: String = queue.reverse.toString > } > > class PersistentSnapshotActor extends PersistentActor with ActorLogging { > override def persistenceId = "snapshot-persistence-id" > > var state = State() > > def updateState(event: Event) = state = state.updated(event) > > def numberOfEvents = state.size > > def receiveRecover = LoggingReceive { > case event: Event => updateState(event) > case SnapshotOffer(_, snapshot: State) => > log.debug(s"offered state: $snapshot") > state = snapshot > } > > def receiveCommand = LoggingReceive { > case Command(data) => persist(Event(data))(updateState) > case Fail => throw new Exception("killing persistent actor.") > case ShutDown => context.stop(self) > case InternalState => println(state) > case TakeSnapshot => saveSnapshot(state) > delete > case SaveSnapshotSuccess => log.debug("snapshot saved successfully.") > case SaveSnapshotFailure(_, reason) => log.error(s"failed to save > snapshot: $reason") > } > } > > object PersistentSnapshotActorApp extends App { > val system = ActorSystem("snapshotSystem") > val persistentActor = system.actorOf(Props[PersistentSnapshotActor], > "persistentSnapshotActor") > > persistentActor ! Command("1") > persistentActor ! Command("2") > persistentActor ! Command("3") > persistentActor ! Command("4") > persistentActor ! TakeSnapshot > persistentActor ! InternalState > persistentActor ! Command("5") > persistentActor ! TakeSnapshot > persistentActor ! Fail > persistentActor ! InternalState > } > > Thanks a lot > -- >>>>>>>>>> Read the docs: http://akka.io/docs/ >>>>>>>>>> Check the FAQ: >>>>>>>>>> http://doc.akka.io/docs/akka/current/additional/faq.html >>>>>>>>>> Search the archives: https://groups.google.com/group/akka-user --- You received this message because you are subscribed to the Google Groups "Akka User List" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/akka-user. For more options, visit https://groups.google.com/d/optout.
