I would probably say complex/fewer MR phases but I guess it would depend on the compute complexity of your functions (in order to take advantage of parallelism/more compute cores). My reasoning is that every time you Map you are reading the full value from disk. More Maps = more disk i/o. Not to mention the erlang to js overhead if you are running js functions.
Please report your findings! Best, -Alexander Sicular @siculars On Mar 14, 2012, at 6:16 PM, Jonathan Langevin wrote: > What is better for performance in Riak? > More phases with simpler logic, or less phases with more complex logic? > > For instance, if I want to check 10 different fields of the result objects, > using 10 different functions, should I combine that all down into 1-2 m/r > phases, or run as 10 different m/r phases? > > I would think more phases would suggest that the workload could be > distributed across various nodes more easily, but few phases would mean that > the values wouldn't have to be processed as many times... > > > Jonathan Langevin > Manager, Information Technology > Loom Inc. > Wilmington, NC: (910) 241-0433 - [email protected] - > www.loomlearning.com - Skype: intel352 > > _______________________________________________ > riak-users mailing list > [email protected] > http://lists.basho.com/mailman/listinfo/riak-users_lists.basho.com
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