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https://issues.apache.org/jira/browse/MAPREDUCE-469?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Greg Roelofs updated MAPREDUCE-469:
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Attachment: grr-hadoop-common.dif.20100614c
grr-hadoop-mapreduce.dif.20100614c
Almost-final gzip concatenation code (several style-related issues to deal
with, but working code, both native and non-native, with no debug statements)
and a halfway test case (need to get bzip2 half working).
Summary: I implemented an Inflater-based Decompressor with "manual" gzip
header/trailer parsing and CRC checks, and added new getRemaining() and
resetPartially() methods to the interface. I also modified DecompressorStream
to support concatenated streams (decompress() and getCompressedData() methods).
For backward compatibility, the default behavior is unchanged; one needs to
set the new io.compression.gzip.concat config option to true to turn it on.
Since bzip2 apparently changed its behavior without such a setting, perhaps
this is overkill...
Anyway, this is against trunk (as of a week or two ago). I still need to check
it against Yahoo's tree, deal with the FIXMEs, update my source tree(s), run
test-patch, etc. Also, I haven't included the (binary) test files here; I'll
do so in one of the next versions of the patch.
> Support concatenated gzip and bzip2 files
> -----------------------------------------
>
> Key: MAPREDUCE-469
> URL: https://issues.apache.org/jira/browse/MAPREDUCE-469
> Project: Hadoop Map/Reduce
> Issue Type: Improvement
> Reporter: Tom White
> Assignee: Greg Roelofs
> Attachments: grr-hadoop-common.dif.20100614c,
> grr-hadoop-mapreduce.dif.20100614c
>
>
> When running MapReduce with concatenated gzip files as input only the first
> part is read, which is confusing, to say the least. Concatenated gzip is
> described in http://www.gnu.org/software/gzip/manual/gzip.html#Advanced-usage
> and in http://www.ietf.org/rfc/rfc1952.txt. (See original report at
> http://www.nabble.com/Problem-with-Hadoop-and-concatenated-gzip-files-to21383097.html)
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