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From "Owen O'Malley (JIRA)" <j...@apache.org>
Subject [jira] Commented: (PIG-42) Pig should be able to split Gzip files like it can split Bzip files
Date Fri, 07 Dec 2007 08:39:42 GMT

    [ https://issues.apache.org/jira/browse/PIG-42?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#action_12549337
] 

Owen O'Malley commented on PIG-42:
----------------------------------

It seems a lot more friendly to define the format like:

{code}
% touch empty
% gzip -nc part0 empty part1 empty part2 empty part3 > big.sgz
{code}

That would let the user do:
{code}
% gzcat big.sgz
{code}

to get their file back. I'd also use filenames rather than a header to reflect whether a file
is in this format, but that is mostly just a personal preference.

> Pig should be able to split Gzip files like it can split Bzip files
> -------------------------------------------------------------------
>
>                 Key: PIG-42
>                 URL: https://issues.apache.org/jira/browse/PIG-42
>             Project: Pig
>          Issue Type: Improvement
>          Components: impl
>            Reporter: Benjamin Reed
>         Attachments: gzip.patch
>
>
> It would be nice to be able to split gzip files like we can split bzip files. Unfortunately,
we don't have a sync point for the split in the gzip format.
> Gzip file format supports the notion of concatenate gzipped files. When gzipped files
are concatenated together they are treated as a single file. So to make a gzipped file splittable
we can used an empty compressed file with some salt in the headers as a sync signature. Then
we can make the gzip file splittable by using this sync signature between compressed segments
of the file.

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