Question

In MongoDB __________ mongos retrieves the results from each shard, performs a merge sort to order the results.

(a) 3.0

(b) 2.0

(c) 1.0

(d) None of the mentioned

This question was posed to me in a job interview.

The doubt is from Map-Reduce and Sharded Collections in portion Aggregation Concepts and Aggregation Mechanics of MongoDB

Answer 1

The correct answer is (b) 2.0

To explain: This model requires only a small amount of memory, even for large data sets.