[Haskell-cafe] Why monoids will abide...

[Tim Newsham]

On Thu, 22 Jan 2009, Eugene Kirpichov wrote:
> To my mind, in the map-reduce case you generally need a commutative
> monoid. Or, you need an extra infrastructure that mappend's only
> results from adjacent machines, or something like that.

The paper
    http://www.cs.vu.nl/~ralf/MapReduce/

analyzes the model of Google's MapReduce and Sawzall.  quick haskell 
summaries at:
    http://www.thenewsh.com/~newsham/x/machine/MapReduce.hs
    http://www.thenewsh.com/~newsham/x/machine/Sawzall.hs

The MapReduce model isn't based directly on a monoid, but the Sawzall 
model is.

Tim Newsham
http://www.thenewsh.com/~newsham/