[
https://issues.apache.org/jira/browse/HADOOP-4620?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12652689#action_12652689
]
Ravi Gummadi commented on HADOOP-4620:
--------------------------------------
So there is no issue of tasks hanging forever(even if the size of the map
output is 0 bytes). I agree that the message "mapRedFinished" is displayed
before output thread and error thread have completed their work. Log messages
will be changed to be displayed appopriately.
Otherwise, please provide a testcase that reproduces the problem of Map Task
hanging. I am not able to reproduce the problem of hanging map task.
> Streaming mapper never completes if the mapper does not write to stdout
> -----------------------------------------------------------------------
>
> Key: HADOOP-4620
> URL: https://issues.apache.org/jira/browse/HADOOP-4620
> Project: Hadoop Core
> Issue Type: Bug
> Components: mapred
> Affects Versions: 0.17.2
> Reporter: Runping Qi
> Assignee: Ravi Gummadi
>
> A mapper of a streaming job has empty input data and thus it produces no
> output.
> The task never completes.
> The following are the last two lines from the task log:
> 2008-11-07 21:59:48,254 INFO org.apache.hadoop.streaming.PipeMapRed:
> PipeMapRed exec [/usr/bin/perl, xxx]
> 2008-11-07 21:59:48,330 INFO org.apache.hadoop.streaming.PipeMapRed:
> mapRedFinished
>
--
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.
