Why MapReduce is important
Tuesday, February 23, 2010
6:03 PM
Why MapReduce is important
The mapping phase is "embarrassingly parallel"; parallel time = (total serial time)/(# of processors). 
Parallelism is ideal; we can't do any better than that!
Time for the reduce phase is proportional to the log of the number of processors utilized. Not quite perfect runtime, but as good as it gets. 