com.twitter.elephantbird.util

Class TaskHeartbeatThread

java.lang.Object

com.twitter.elephantbird.util.TaskHeartbeatThread

public class TaskHeartbeatThread
extends Object

Keeps a task alive during any slow operations

Author:

Alex Levenson

Constructor Summary

Constructors

Constructor and Description
TaskHeartbeatThread(org.apache.hadoop.util.Progressable context, long periodMillis) Creates a new thread to keep a task alive Does not start the thread until you call start()
TaskHeartbeatThread(org.apache.hadoop.mapreduce.TaskAttemptContext context) Same as #TaskHeartbeatThread(TaskAttemptContext, long) but with a default period of 1 minute

Method Summary

Methods

Modifier and Type	Method and Description
protected void	progress() This will be called once every periodMillis.
void	start() Keep the task alive until stop() is called
void	stop() Stop keeping the task alive, make sure to call this when your slow operation is finished.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

TaskHeartbeatThread

public TaskHeartbeatThread(org.apache.hadoop.util.Progressable context,
                   long periodMillis)

Creates a new thread to keep a task alive Does not start the thread until you call start()

Parameters:

context - the task attempt context, used to send progress signals to the task

periodMillis - how often to wake up and send a progress signal in milliseconds

TaskHeartbeatThread

public TaskHeartbeatThread(org.apache.hadoop.mapreduce.TaskAttemptContext context)

Same as #TaskHeartbeatThread(TaskAttemptContext, long) but with a default period of 1 minute

Method Detail

start

public void start()

Keep the task alive until stop() is called

stop

public void stop()

Stop keeping the task alive, make sure to call this when your slow operation is finished. It's a good idea to wrap your slow code with a try { ... } finally {heartBeat.stop()}} to ensure that the heartBeat is stopped. If the heartBeat remains alive failed jobs can remain 'running' indefinitely.

progress

protected void progress()

This will be called once every periodMillis. Override to report progress of the slow close() method