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https://issues.apache.org/jira/browse/HADOOP-153?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12593052#action_12593052
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Joydeep Sen Sarma commented on HADOOP-153:
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i am missing something .. whatever the framework can do using the 
recordreader's new interfaces - the recordreader can do itself. If the 
recordreader can define record boundaries and skip to the next record - then it 
can catch any and all exceptions that it might throw and ignore the bad record 
and move to the next one without involving the framework.

sorry if i am being totally obtuse here - just not getting it ..

> skip records that throw exceptions
> ----------------------------------
>
>                 Key: HADOOP-153
>                 URL: https://issues.apache.org/jira/browse/HADOOP-153
>             Project: Hadoop Core
>          Issue Type: New Feature
>          Components: mapred
>    Affects Versions: 0.2.0
>            Reporter: Doug Cutting
>            Assignee: Devaraj Das
>
> MapReduce should skip records that throw exceptions.
> If the exception is thrown under RecordReader.next() then RecordReader 
> implementations should automatically skip to the start of a subsequent record.
> Exceptions in map and reduce implementations can simply be logged, unless 
> they happen under RecordWriter.write().  Cancelling partial output could be 
> hard.  So such output errors will still result in task failure.
> This behaviour should be optional, but enabled by default.  A count of errors 
> per task and job should be maintained and displayed in the web ui.  Perhaps 
> if some percentage of records (>50%?) result in exceptions then the task 
> should fail.  This would stop jobs early that are misconfigured or have buggy 
> code.
> Thoughts?

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