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From jason hadoop <jason.had...@gmail.com>
Subject Re: Is Mapper's map method thread safe?
Date Thu, 14 May 2009 06:17:25 GMT
Ultimately it depends on how you write the Mapper.map method.
The framework supports a MultithreadedMapRunner which lets you set the
number of threads running your map method simultaneously.
Chapter 5 of my book covers this.


On Wed, May 13, 2009 at 11:10 PM, Shengkai Zhu <geniusjash@gmail.com> wrote:

> Each mapper instance will be executed in separate JVM.
>
> On Thu, May 14, 2009 at 2:04 PM, imcaptor <imcaptor@gmail.com> wrote:
>
> > Dear all:
> >
> > Any one knows Is Mapper's map method thread safe?
> > Thank you!
> >
> > imcaptor
> >
>
>
>
> --
>
> 朱盛凯
>
> Jash Zhu
>
> 复旦大学软件学院
>
> Software School, Fudan University
>



-- 
Alpha Chapters of my book on Hadoop are available
http://www.apress.com/book/view/9781430219422
www.prohadoopbook.com a community for Hadoop Professionals

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