Briefing Cloudera Knowledge

how many distinct copy operations will there be in the sort/shuffle phase?

In a large MapReduce job with m mappers and n reducers, how many distinct copy operations will
there be in the sort/shuffle phase?

A.
mXn (i.e., m multiplied by n)

B.
n

C.
m

D.
m+n (i.e., m plus n)

E.
mn (i.e., m to the power of n)

Explanation:
A MapReduce job with m mappers and r reducers involves up to m * r distinct copy
operations, since each mapper may have intermediate output going to every reducer.