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https://issues.apache.org/jira/browse/HADOOP-153?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12593060#action_12593060
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Yiping Han commented on HADOOP-153:
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In our user case, when re-execute, we do not want to skip those killer records. 
Instead, in our user-supplied mapper we want to be able to identify them such 
that we can take a different code path to specialize them. So, we would like to 
see during re-executing, the records are marked by a flag indicating they are 
killer records in the previous runs. Or any alternatives that could give us the 
same information would help.

> 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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