What are the limitations of map reduce in the sense of the types of computations that they can express? Is Map Reduce "turning complete"?
I have been told that map reduce only works on things that can be expressed in the Map and Reduce framework, but my question is, why can't everything be expressed like that?
This might be the reason why Distributed Shared Memory systems like tread marks or IVY started to exist. So that we could express general programs and deal with them in a distributed computing manner.
Can someone give me an example of a task that can be done in a DMS and one that cannot be in map reduce? Or maybe, is there a formal theorem or proof showing what things can't be done in MapReduce but that a general programing language can do? What are the inherit limitations of Map Reduce and why are they the way it is?