An application team complains that the DocumentDB cluster takes a long time to return query results. What actions can be performed to solve this issue (Select TWO)?

Answer options:

A.Set “tls” parameter to “disabled”.
B.Configure MongoDB cluster with “primaryPreferred”.
C.Configure MongoDB cluster with “secondaryPreferred”.
D.Create an index on the field being queried.
E.Set the instance class to db.r4.large.

Answer: C and D
Option A is incorrect because setting the “tls” parameter to “disabled” turns off transport layer security (TLS) for client connections. This would not speed up query results, but would decrease the security of the database.
Option B is incorrect because setting “primaryPreferred” read preference routes read operations to the primary instance. This would not increase the efficiency of query. It may decrease the performance of the cluster since all requests would be going to the primary instance.
Option C is CORRECT because setting the “secondaryPreferred” read preference option distributes requests to read replicas. This is recommended as it increases the performance efficiency of the database cluster.
Option D is CORRECT because creating an index on the field being queried speeds up the query operations.
Option E is incorrect because db.r4.large is the smallest instance class for DocumentDB instances.
Reference:
https://docs.aws.amazon.com/documentdb/latest/developerguide/user_diagnostics.html#user_diagnostics-identify_unused_indexes
https://docs.aws.amazon.com/documentdb/latest/developerguide/how-it-works.html#durability-consistency-isolation