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Date: Mon, 14 Jul 2008 12:04:31 -0700 (PDT)
From: "Chris Douglas (JIRA)" <jira@apache.org>
To: core-dev@hadoop.apache.org
Subject: [jira] Updated: (HADOOP-3646) Providing bzip2 as codec
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     [ https://issues.apache.org/jira/browse/HADOOP-3646?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Chris Douglas updated HADOOP-3646:
----------------------------------

    Assignee: Abdul Qadeer
      Status: Patch Available  (was: Reopened)

> Providing bzip2 as codec
> ------------------------
>
>                 Key: HADOOP-3646
>                 URL: https://issues.apache.org/jira/browse/HADOOP-3646
>             Project: Hadoop Core
>          Issue Type: Improvement
>          Components: conf, io
>    Affects Versions: 0.19.0
>            Reporter: Abdul Qadeer
>            Assignee: Abdul Qadeer
>             Fix For: 0.19.0
>
>         Attachments: HADOOP-3646.patch, HADOOP-3646.patch
>
>   Original Estimate: 1008h
>  Remaining Estimate: 1008h
>
> Hadoop recognizes gzip compressed input and automatically decompresses the data before providing it to the mapper. But Hadoop can not split a gzip stream due to the very nature of the gzip compression. Consequently one gzip stream (e.g a whole file) can go to only one mapper.  On the contrary Bzip2 compressed stream can be split across its block delimiters.
> We are interested in extending Hadoop to support splittable bzip2 with a codec.  (https://issues.apache.org/jira/browse/HADOOP-1823  uses input reader to split the bzip2 files, which must be provided by the user and can handle FileInputFormat.  If a user wants to use some other input format or wants to do custom record handling, he must write a new input reader!)
> We have a patch now that provides a basic bzip2 codec equivalent to the current gzip codec.  We are in the process of extending that to support splitting.

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