Pass4sure CCD-410 Question Answer

How are keys and values presented and passed to the reducers during a standard sort and shuffle phase of MapReduce?

A. Keys are presented to reducer in sorted order; values for a given key are not sorted.
B. Keys are presented to reducer in sorted order; values for a given key are sorted in ascending order.
C. Keys are presented to a reducer in random order; values for a given key are not sorted.
D. Keys are presented to a reducer in random order; values for a given key are sorted in ascending order.

Answer: A                                                  

Assuming default settings, which best describes the order of data provided to a reducer’s reduce method:

A. The keys given to a reducer aren’t in a predictable order, but the values associated with those keys always are.
B. Both the keys and values passed to a reducer always appear in sorted order.
C. Neither keys nor values are in any predictable order.
D. The keys given to a reducer are in sorted order but the values associated with each key are in no predictable order

Answer: D