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From "eric baldeschwieler (JIRA)" <j...@apache.org>
Subject [jira] Commented: (HADOOP-2429) The lowest level map-reduce APIs should be byte oriented
Date Fri, 14 Mar 2008 05:41:24 GMT

    [ https://issues.apache.org/jira/browse/HADOOP-2429?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12578622#action_12578622
] 

eric baldeschwieler commented on HADOOP-2429:
---------------------------------------------

owen, runping, I disagree completely with the assumptions from which you reach your conclusions.

I think you are not looking at the total system costs.  This design ends up spewing java types
everywhere.  The fact of the matter is our average user is not using java to code.  Even in
Java we end up doing gymnastics to support standard types and it is making multi-language
interoperability difficult and non-standard.  Types end up polluting all of our containers
too.  This makes them non-interoperable.

And after paying all this cost, we still end up compromising the integrity of the type based
design, because one can not efficiently merge/sort if one must instantiate objects to do it,
so we require the writing of byte based comparators.  Yuck!

I'm interested in suggestions for a compromise design that raises other languages to first
order citizens in Hadoop and keeps us from having to do gymnastics to use even native java
types.

> 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.

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