What is Shuffling in MapReduce?
Posted in Hadoop, Hadoop Interview Questions, Interview Questions by Sujith Reddy Pelleti On April 29, 2015. No comments
Shuffling in MapReduce
As the Reducer receives the Mapper output which is also called as Intermediate Data as its input, it has to make sure that the Reducer receives the data sorted on its Key. For this purpose all the Unique keys are pulled together and sorted and sent to the Reducer. This phase is called Shuffling in MapReduce.
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