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From "Jason Lowe (JIRA)" <j...@apache.org>
Subject [jira] [Updated] (HADOOP-9867) org.apache.hadoop.mapred.LineRecordReader does not handle multibyte record delimiters well
Date Tue, 19 Nov 2013 19:15:21 GMT

     [ https://issues.apache.org/jira/browse/HADOOP-9867?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel

Jason Lowe updated HADOOP-9867:

             Priority: Critical  (was: Major)
     Target Version/s: 2.3.0
    Affects Version/s: 0.23.9

Raising severity since this involves loss of data.  Also I confirmed this is an issue on recent
Hadoop versions as well.

> org.apache.hadoop.mapred.LineRecordReader does not handle multibyte record delimiters
> ------------------------------------------------------------------------------------------
>                 Key: HADOOP-9867
>                 URL: https://issues.apache.org/jira/browse/HADOOP-9867
>             Project: Hadoop Common
>          Issue Type: Bug
>          Components: io
>    Affects Versions: 0.20.2, 0.23.9, 2.2.0
>         Environment: CDH3U2 Redhat linux 5.7
>            Reporter: Kris Geusebroek
>            Priority: Critical
> Having defined a recorddelimiter of multiple bytes in a new InputFileFormat sometimes
has the effect of skipping records from the input.
> This happens when the input splits are split off just after a recordseparator. Starting
point for the next split would be non zero and skipFirstLine would be true. A seek into the
file is done to start - 1 and the text until the first recorddelimiter is ignored (due to
the presumption that this record is already handled by the previous maptask). Since the re
ord delimiter is multibyte the seek only got the last byte of the delimiter into scope and
its not recognized as a full delimiter. So the text is skipped until the next delimiter (ignoring
a full record!!)

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