How to modify the Map-Reduce execution order?

[Anh Pham <ph...@gmail.com>]

(Please correct me if I am wrong) So the original chain is:
InputSplits-->Mapper--> [Sorting/Shuffling, etc]-->Reducer-->...

Now I don't want the input splits to get to the Mappers first, but to go to
some other new stage instead (we can call it Pre-Mapper for example, this
class will be created by myself).

So the new order will be: InputSplits -> Pre-Mapper->Mapper ->...

I'm currently reading the source code. However, I still cannot find any
clue (what classes I should touch). Any suggestion is welcome. Thank you
very much :)

Re: How to modify the Map-Reduce execution order?

[Arun C Murthy <ac...@hortonworks.com>]

You might be interested in Apache Tez which provides native support for these sort of scenarios by being a super-set of MapReduce:

http://tez.incubator.apache.org/

Arun

On Oct 16, 2013, at 1:16 AM, Anh Pham <ph...@gmail.com> wrote:

> (Please correct me if I am wrong) So the original chain is:
> InputSplits-->Mapper--> [Sorting/Shuffling, etc]-->Reducer-->...
> 
> Now I don't want the input splits to get to the Mappers first, but to go to
> some other new stage instead (we can call it Pre-Mapper for example, this
> class will be created by myself).
> 
> So the new order will be: InputSplits -> Pre-Mapper->Mapper ->...
> 
> I'm currently reading the source code. However, I still cannot find any
> clue (what classes I should touch). Any suggestion is welcome. Thank you
> very much :)

--
Arun C. Murthy
Hortonworks Inc.
http://hortonworks.com/



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Re: How to modify the Map-Reduce execution order?

[Tsuyoshi OZAWA <oz...@gmail.com>]

Hi Anh,

How about using ChainMapper? Is the helpful for you?
http://hadoop.apache.org/docs/current/api/org/apache/hadoop/mapred/lib/ChainMapper.html

Thanks, Tsuyoshi

On Wed, Oct 16, 2013 at 1:16 AM, Anh Pham <ph...@gmail.com> wrote:
> (Please correct me if I am wrong) So the original chain is:
> InputSplits-->Mapper--> [Sorting/Shuffling, etc]-->Reducer-->...
>
> Now I don't want the input splits to get to the Mappers first, but to go to
> some other new stage instead (we can call it Pre-Mapper for example, this
> class will be created by myself).
>
> So the new order will be: InputSplits -> Pre-Mapper->Mapper ->...
>
> I'm currently reading the source code. However, I still cannot find any
> clue (what classes I should touch). Any suggestion is welcome. Thank you
> very much :)



-- 
- Tsuyoshi