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From "Devaraj Das (JIRA)" <j...@apache.org>
Subject [jira] Commented: (HADOOP-1722) Make streaming to handle non-utf8 byte array
Date Wed, 04 Feb 2009 06:41:59 GMT

    [ https://issues.apache.org/jira/browse/HADOOP-1722?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12670258#action_12670258
] 

Devaraj Das commented on HADOOP-1722:
-------------------------------------

Looks good overall! The one thing that should be considered here is moving the typedBytes
package from core to streaming. Is there currently a usecase where typedBytes might be used
elsewhere? The same argument holds for DumpTypedBytes & AutoInputFormat as well. Could
we have the DumpTypedBytes integrated with StreamJob (as in, if someone wants to test out
things, he uses the streaming.jar and passes an option to invoke DumpTypedBytes tool).
The other thing is about special handling for the basic types, as opposed to using raw bytes
for everything. How typical is the use case where we have Key/Value types as the basic types.
I understand that it makes the on-disk/wire representation compact in the cases where the
native types are used, but it would simplify the framework if we dealt with only raw bytes
instead (and probably use compression).
It would help if you include an example of a streaming app where binary data is consumed/produced.


> Make streaming to handle non-utf8 byte array
> --------------------------------------------
>
>                 Key: HADOOP-1722
>                 URL: https://issues.apache.org/jira/browse/HADOOP-1722
>             Project: Hadoop Core
>          Issue Type: Improvement
>          Components: contrib/streaming
>            Reporter: Runping Qi
>            Assignee: Klaas Bosteels
>         Attachments: HADOOP-1722-v2.patch, HADOOP-1722-v3.patch, HADOOP-1722-v4.patch,
HADOOP-1722.patch
>
>
> Right now, the streaming framework expects the output sof the steam process (mapper or
reducer) are line 
> oriented UTF-8 text. This limit makes it impossible to use those programs whose outputs
may be non-UTF-8
>  (international encoding, or maybe even binary data). Streaming can overcome this limit
by introducing a simple
> encoding protocol. For example, it can allow the mapper/reducer to hexencode its keys/values,

> the framework decodes them in the Java side.
> This way, as long as the mapper/reducer executables follow this encoding protocol, 
> they can output arabitary bytearray and the streaming framework can handle them.

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