Class WorkerService

java.lang.Object
org.apache.zookeeper.server.WorkerService

public class WorkerService extends Object
WorkerService is a worker thread pool for running tasks and is implemented using one or more ExecutorServices. A WorkerService can support assignable threads, which it does by creating N separate single thread ExecutorServices, or non-assignable threads, which it does by creating a single N-thread ExecutorService. - NIOServerCnxnFactory uses a non-assignable WorkerService because the socket IO requests are order independent and allowing the ExecutorService to handle thread assignment gives optimal performance. - CommitProcessor uses an assignable WorkerService because requests for a given session must be processed in order. ExecutorService provides queue management and thread restarting, so it's useful even with a single thread.
  • Constructor Details

    • WorkerService

      public WorkerService(String name, int numThreads, boolean useAssignableThreads)
      Parameters:
      name - worker threads are named <name>Thread-##
      numThreads - number of worker threads (0 - N) If 0, scheduled work is run immediately by the calling thread.
      useAssignableThreads - whether the worker threads should be individually assignable or not
  • Method Details

    • schedule

      public void schedule(WorkerService.WorkRequest workRequest)
      Schedule work to be done. If a worker thread pool is not being used, work is done directly by this thread. This schedule API is for use with non-assignable WorkerServices. For assignable WorkerServices, will always run on the first thread.
    • schedule

      public void schedule(WorkerService.WorkRequest workRequest, long id)
      Schedule work to be done by the thread assigned to this id. Thread assignment is a single mod operation on the number of threads. If a worker thread pool is not being used, work is done directly by this thread.
    • start

      public void start()
    • stop

      public void stop()
    • join

      public void join(long shutdownTimeoutMS)