In a large MapReduce job with m mappers and r reducers, how many distinct copy operations will
there be in the sort/shuffle phase?
A.
m
B.
r
C.
m+r (i.e., m plus r)
D.
mxr (i.e., m multiplied by r)
E.
mr (i.e., m to the power of r)
Explanation:
A MapReduce job withm mappers and r reducers involves up to m*r distinct copy
operations, since eachmapper may have intermediate output going to every reducer.