What is shuffling in MapReduce?

Shuffling is the process of transferring the data from mapper machine to the reducer machine.

 

What is the order of mapper, partition, shuffling, sorting and reducer phases?

Mapper -> Partitioner -> Shuffle -> Sort -> Reducer

 

Is shuffling process occur on MapOnly Job?

Shuffling do not occur when the number of reducers are set to 0.

 

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