In the last post we saw how to run a MapReduce job on Hadoop. Now we're going to analyze how a MapReduce program works. And, if you don't know what MapReduce is, the short answer is "MapReduce is a programming model for processing large data sets wit…
In the last post we saw how to write a MapReduce program for finding the top-n items of a dataset. The code in the mapper emits a pair key-value for every word found, passing the word as the key and 1 as the value. Since the book has roughly 38,000 w…
