[jira] Resolved: (HADOOP-156) Reducer threw IOEOFException

["Owen O'Malley (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/HADOOP-156?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Owen O'Malley resolved HADOOP-156.
----------------------------------

    Resolution: Cannot Reproduce

I suspect this was one of the race conditions and that part of the code has changed completely since this was filed.

> Reducer  threw IOEOFException
> -----------------------------
>
>                 Key: HADOOP-156
>                 URL: https://issues.apache.org/jira/browse/HADOOP-156
>             Project: Hadoop Core
>          Issue Type: Bug
>          Components: mapred
>    Affects Versions: 0.3.0
>            Reporter: Runping Qi
>            Assignee: Owen O'Malley
>
> A job was running with all the map tasks completed.
> The reducers were appending the intermediate files into the large intermediate file.
> java.io.EOFException was thrown when the record reader tried to read the version number
> during initialization. Here is the stack trace:
> java.io.EOFException 
>     at java.io.DataInputStream.readFully(DataInputStream.java:178) 
>     at java.io.DataInputStream.readFully(DataInputStream.java:152) 
>     at org.apache.hadoop.io.SequenceFile$Reader.init(SequenceFile.java:251) 
>     at org.apache.hadoop.io.SequenceFile$Reader.(SequenceFile.java:236) 
>     at org.apache.hadoop.io.SequenceFile$Reader.(SequenceFile.java:226) 
>     at org.apache.hadoop.mapred.ReduceTask.run(ReduceTask.java:205) 
>     at org.apache.hadoop.mapred.TaskTracker$Child.main(TaskTracker.java:709) 
> Appearantly, the intermediate file was empty. I suspect that one map task
> generated empty intermidiate files for all the reducers, since all the reducers
> failed at the same place, and failed at the same place during retries.
> Unfortunately, we cannot know which map task generated the empty files,
> since the exception does not offer any clue.
> One simple enhancement is that the record reader should catch IOException and re-throw it with additional 
> information, such as the file name.

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