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Subject: Re: [boost] RFC - Updated MapReduce library
From: joel (joel.falcou_at_[hidden])
Date: 2009-08-09 12:31:31

Craig Henderson wrote:
> I think we're misunderstanding each other. My point is that if it is an
> instance of a functor, then the developer may be tempted to presume a state
> of the object and store instance data. This is invalid as the map task
> object is created, used and then destroyed. Any attempt to share data
> between map objects breaks the MapReduce design and scalability properties
> (which need to be preserved for loyalty to the MapReduce paradigm and for
> future multi-machine scalability).
Well that's a problem with any kind of functor anyway. There is the same
problem with Boost.Thread where you should be aware of the internal copy
of the functor object etc...

Just document what happens with the functor I guess.

Joel Falcou - Assistant Professor
PARALL Team - LRI - Universite Paris Sud XI
Tel : (+33)1 69 15 66 35

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