It sounds like there is a typo, I would assume that it should be "the input of later evaluations will include the output of earlier evaluations". It's not really a reduction otherwise.
On Mon, Jul 25, 2011 at 3:03 PM, Brian Rowe <[email protected]> wrote: > Hello, > > I see the following on the Basho wiki for Riak [1]: > > The important thing to understand is that the function defining the > reduce phase may be evaluated multiple times, and the input of later > evaluations will include the input of earlier evaluations. > For example, a reduce phase may implement the set-union function. In > that case, the first set of inputs might be [1,2,2,3], and the output > would be [1,2,3]. When the phase receives more inputs, say [3,4,5], > the function will be called with the concatentation of the two lists: > [1,2,3,4,5]. > > This description isn't clear to me as the behavior I'm seeing is that > the _output_ of earlier evaluations is included as input to later > evaluations. Unfortunately, the example yields the same results > irrespective of whether it is the input or the output of the first > evaluation, so it doesn't clear anything up. > > Thanks, > Brian > > > [1] http://wiki.basho.com/MapReduce.html > > _______________________________________________ > riak-users mailing list > [email protected] > http://lists.basho.com/mailman/listinfo/riak-users_lists.basho.com > _______________________________________________ riak-users mailing list [email protected] http://lists.basho.com/mailman/listinfo/riak-users_lists.basho.com
