CODEWITHSUNDEEP
javaspringdistributed-computinghazelcasthazelcast-imap
slippery
slippery

Reputation: 365

Hazelcast ScheduledExecutorService

Using ScheduledExecutorService from hazelcast 3.8 i've got an out of memory exception. The thing is i'm making a service which should remind to user about some event during a day. Execution of task should be fault-tolerant. A user sets new reminder which is a task for ScheduledExecutorService, thus amount of tasks can be several thousands per day. Each task adds to scheduler as one-shot action using schedule(Runnable command, long delay, TimeUnit unit). A delay can't be longer then 24 hours. When i've started to make tests and add tasks in loop, i've got an oom exception. I thought a task after execution will be removed from memory, but probably i was wrong.

Can you answer for several question:

  1. Should a task be removed from memory after execution?
  2. Is there any setting to do that?
  3. Can i use ScheduledExecutorService for a lot of one-shot action tasks?
  4. Is there another way to solve my task with hazelcast bit don't using a ScheduledExecutorService

Upvotes: 2

Views: 2905

Answers (2)

Hiten
Hiten

Reputation: 53

We are using schedule executor service to run a Runnable Task after certain delay but looks like task was not removed from memory after execution. We are validating by iterating through executorService.getAllScheduledFutures() and check the size.

Upvotes: 0

Terry Walters
Terry Walters

Reputation: 261

  1. Yes
  2. future.dispose();
  3. Yes
  4. Yes you could have the scheduled executor service run at a certain frequency and it could check that users preferences if the service execution is the same for all the iterations.

        HazelcastInstance instance = Hazelcast.newHazelcastInstance();

        IScheduledExecutorService scheduler = instance.getScheduledExecutorService("scheduler");
        IScheduledFuture future = scheduler.schedule(named("MyTask",
                new EchoTask("foobar")), 1, TimeUnit.SECONDS);

        Object result = future.get();
        System.out.println(future.getHandler().getTaskName() + " result: " + result);

        future.dispose();

        System.out.println("Press any key to exit");
        System.in.read();
        Hazelcast.shutdownAll();

Upvotes: 2

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