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From "Runping Qi (JIRA)" <j...@apache.org>
Subject [jira] Commented: (HADOOP-2429) The lowest level map-reduce APIs should be byte oriented
Date Fri, 14 Dec 2007 20:05:43 GMT

    [ https://issues.apache.org/jira/browse/HADOOP-2429?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#action_12551923
] 

Runping Qi commented on HADOOP-2429:
------------------------------------

+1

To enforce that, the API should use concrete classes (such as Buffer) instead of interface
classes such as ByteWritable.

One difficult, though, is the implementation of key based  comparison and
sorting. To perform key comparison, the framework may have to
deserialize them, unless making it mandatory for the application to 
provide a bytes based comparison function. 


> The lowest level map-reduce APIs should be byte oriented
> --------------------------------------------------------
>
>                 Key: HADOOP-2429
>                 URL: https://issues.apache.org/jira/browse/HADOOP-2429
>             Project: Hadoop
>          Issue Type: Improvement
>            Reporter: eric baldeschwieler
>
> As discussed here:
> https://issues.apache.org/jira/browse/HADOOP-1986#action_12551237
> The templates, serializers and other complexities that allow map-reduce to use arbitrary
types complicate the design and lead to lots of object creates and other overhead that a byte
oriented design would not suffer.  I believe the lowest level implementation of hadoop map-reduce
should have byte string oriented APIs (for keys and values).  This API would be more performant,
simpler and more easily cross language.
> The existing API could be maintained as a thin layer on top of the leaner API.

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