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https://issues.apache.org/jira/browse/HADOOP-3646?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12612247#action_12612247
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Chris Douglas commented on HADOOP-3646:
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A few nits:
* Please remove the {{//...............}} and {{//*****//}} comments completely
or replace them with meaningful javadoc
* FeatureNotImplemented Exception can be replaced with
UnsupportedOperationException
* WrongBZip2Header can be replaced by an IOException with a meaningful
description
* Several close() methods contain commented-out code
* Instead of returning null for methods like create(De|C)ompressor, throwing
UnsupportedOperationException is preferred.
* createInputStream and createOutputStream in Bzip2Codec should not simply
ignore the Decompressor/Compressor, but throw an exception. This isn't really a
problem- since one can't obtain these from the codec- but it's worth fixing.
* createInputStream should not swallow the exception; changing WrongBZip2Header
to an IOException should remove the need for this, anyway
* The change to CompressionCodecFactory should be reverted; it's sufficient to
add Bzip2Codec to the config
I tried running wordcount on some sample bzip text and this worked perfectly.
> 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
> Fix For: 0.19.0
>
> Attachments: 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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