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From "Eli Collins (JIRA)" <j...@apache.org>
Subject [jira] [Resolved] (HADOOP-4022) mapper output truncated on pseudo-distributed cluster
Date Thu, 11 Aug 2011 18:28:27 GMT

     [ https://issues.apache.org/jira/browse/HADOOP-4022?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel

Eli Collins resolved HADOOP-4022.

    Resolution: Won't Fix

Out of date

> mapper output truncated on pseudo-distributed cluster
> -----------------------------------------------------
>                 Key: HADOOP-4022
>                 URL: https://issues.apache.org/jira/browse/HADOOP-4022
>             Project: Hadoop Common
>          Issue Type: Bug
>    Affects Versions: 0.17.0, 0.18.0
>            Reporter: Karl Anderson
> On a pseudo-distributed test run, I'm seeing truncated mapper output.  I don't see this
when running the same job on a real cluster managed with hadoop-ec2.
> With a no-reducers streaming job, I'm getting several output files, each truncated to
325.24 KB, and several zero-length output files.  With "cat" as my reducer, I get one output
file, again truncated to 325.24 KB.  This only happens in a pseudo-distributed Hadoop run
- when I run the mapper on the command line (cat input_file | ./mapper.py | sort), I get the
full output.  Input splitting isn't a factor, my input file is small enough to fit in one
input split (and truncated input would just break the mapper, not truncate its output).
> My mapper is outputting the default key-value lines for streaming, with a tab separating
the key and the value, and no newlines or tabs in the value.
> Truncation happens in the middle of a line.  My lines are very long, the lines themselves
are over 325.24 KB.  This isn't the most efficient use of Hadoop, I know, I'm just putting
a job in my pipeline while I work on a better implementation.

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