Question

Point out the wrong statement.

(a) The query scans the index and the collection

(b) An index supports a query when the index contains all the fields scanned by the query

(c) Creating indexes that support queries results in greatly increased query performance

(d) None of the mentioned

This question was addressed to me during a job interview.

This intriguing question comes from Indexing Strategies topic in section Index/Indexing Concepts of MongoDB

Answer 1

Right answer is (a) The query scans the index and the collection

Best explanation: The query scans the index and not the collection.