Question

Point out the wrong statement.

(a) Map-reduce cannot have a finalize stage to make final modifications to the result

(b) Map-reduce is less efficient and more complex than the aggregation pipeline

(c) Specifically, a user with the userAdmin role can grant itself any privilege in the database

(d) All of the mentioned

The question was asked in class test.

My doubt stems from Aggregation topic in division Aggregation Concepts and Aggregation Mechanics of MongoDB

Answer 1

Right answer is (a) Map-reduce cannot have a finalize stage to make final modifications to the result

Easy explanation: In general, map-reduce operations have two phases: a map stage that processes each document and emits one or more objects for each input document, and reduce phase that combines the output of the map operation.