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Posted to mapreduce-issues@hadoop.apache.org by "Johannes Zillmann (JIRA)" <ji...@apache.org> on 2013/07/02 11:28:19 UTC

[jira] [Commented] (MAPREDUCE-5369) Progress for jobs with multiple splits in local mode is wrong

    [ https://issues.apache.org/jira/browse/MAPREDUCE-5369?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13697626#comment-13697626 ] 

Johannes Zillmann commented on MAPREDUCE-5369:
----------------------------------------------

Update: tested that with cdh4.3 and the problem does not exists anymore in that version. So it might be fixed somewhere along the 2.x branch.
                
> 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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