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From "Johannes Zillmann (JIRA)" <j...@apache.org>
Subject [jira] [Created] (MAPREDUCE-5369) Progress for jobs with multiple splits in local mode is wrong
Date Tue, 02 Jul 2013 08:50:28 GMT
Johannes Zillmann created MAPREDUCE-5369:
--------------------------------------------

             Summary: Progress for jobs with multiple splits in local mode is wrong
                 Key: MAPREDUCE-5369
                 URL: https://issues.apache.org/jira/browse/MAPREDUCE-5369
             Project: Hadoop Map/Reduce
          Issue Type: Bug
    Affects Versions: 0.20.2
            Reporter: Johannes Zillmann


In case a job with multiple splits is executed in local mode (LocalJobRunner) its progress
calculation is wrong.
After the first split is processed it jumps to 100%, then back to 50% and so on. 

The reason lies in the progress calculation in LocalJobRunner:
{code}
      float taskIndex = mapIds.indexOf(taskId);
      if (taskIndex >= 0) {                       // mapping
        float numTasks = mapIds.size();
        status.setMapProgress(taskIndex/numTasks + taskStatus.getProgress()/numTasks);
      } else {
        status.setReduceProgress(taskStatus.getProgress());
      }
{code}

The problem is that {{mapIds}} is filled lazily in run(). There is an loop over all splits.
In the loop, the splits task id is added to {{mapIds}}, then the split is processed. That
means {{numTasks}} is 1 while the first split is processed, it is 2 while the second task
is processed and so on...

I tried Hadoop 0.20.2, 1.0.3, 1.1.2 and cdh-4.1. All the same behaviour!

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