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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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