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[ https://issues.apache.org/jira/browse/HADOOP-2429?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12644797#action_12644797 ]

Chris Dyer commented on HADOOP-2429:
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I think this seems like a very prudent suggestion, especially with respect to adding support for non-Java mappers and reducers that aren't forced to do everything with text. As for my understanding of what is typical at Google, serialization is handled in the mappers and reducers (often using protocol buffers, which incorporate a more efficient encoding for integers, etc.) and there are indeed many useful cases where complete deserialization is unnecessary and even where simple identity mapping/reducing is useful.

Is there any chance that this issue is going to be acted on? As someone who needs to do work in c++ (without linking in a JVM -- we have memory requirements as well), I've been hesitant to embrace Hadoop too fully since the restrictions that it imposes on non-Java code are substantial...
The lowest level map-reduce APIs should be byte oriented
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Key: HADOOP-2429
URL: https://issues.apache.org/jira/browse/HADOOP-2429
Project: Hadoop Core
Issue Type: Improvement
Components: mapred
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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  • Owen O'Malley (JIRA) at Nov 6, 2008 at 6:02 am
    [ https://issues.apache.org/jira/browse/HADOOP-2429?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12645404#action_12645404 ]

    Owen O'Malley commented on HADOOP-2429:
    ---------------------------------------

    The API in C++ is completely byte-based. It uses std::string, but treats them as raw byte containers. (The C++ interface for map/reduce does not use JNI. It uses an external process that communicates via a socket.)
    The lowest level map-reduce APIs should be byte oriented
    --------------------------------------------------------

    Key: HADOOP-2429
    URL: https://issues.apache.org/jira/browse/HADOOP-2429
    Project: Hadoop Core
    Issue Type: Improvement
    Components: mapred
    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.
    --
    This message is automatically generated by JIRA.
    -
    You can reply to this email to add a comment to the issue online.

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postedNov 3, '08 at 8:17p
activeNov 6, '08 at 6:02a
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