/// <summary>Child checking whether it can commit.</summary>
/// <remarks>
/// Child checking whether it can commit.
/// <br />
/// Commit is a two-phased protocol. First the attempt informs the
/// ApplicationMaster that it is
/// <see cref="CommitPending(TaskAttemptID, TaskStatus)"/>
/// . Then it repeatedly polls
/// the ApplicationMaster whether it
/// <see cref="CanCommit(TaskAttemptID)"/>
/// This is
/// a legacy from the centralized commit protocol handling by the JobTracker.
/// </remarks>
/// <exception cref="System.IO.IOException"/>
public virtual bool CanCommit(TaskAttemptID taskAttemptID)
{
Log.Info("Commit go/no-go request from " + taskAttemptID.ToString());
// An attempt is asking if it can commit its output. This can be decided
// only by the task which is managing the multiple attempts. So redirect the
// request there.
TaskAttemptId attemptID = TypeConverter.ToYarn(taskAttemptID);
taskHeartbeatHandler.Progressing(attemptID);
// tell task to retry later if AM has not heard from RM within the commit
// window to help avoid double-committing in a split-brain situation
long now = context.GetClock().GetTime();
if (now - rmHeartbeatHandler.GetLastHeartbeatTime() > commitWindowMs)
{
return(false);
}
Org.Apache.Hadoop.Mapreduce.V2.App.Job.Job job = context.GetJob(attemptID.GetTaskId
().GetJobId());
Task task = job.GetTask(attemptID.GetTaskId());
return(task.CanCommit(attemptID));
}
