An application team complains that the DocumentDB cluster takes a long time to return query results. What can a database specialist use to investigate the query execution plan and analyze the query performance?

Answer options:

A.CloudWatch Logs
B.CloudTrail Events
C.AWS X-Ray
D.MongoDB explain() method

Answer: D
Option A is incorrect because CloudWatch logs do not contain details of DocumentDB query execution plans.
Option B is incorrect because CloudTrail is a log of AWS services API activity. It cannot be used for monitoring and analyzing the performance of DocumentDB databases.
Option C is incorrect because AWS X-Ray is used for debugging and tracing requests in microservices applications.
Option D is CORRECT because db.runCommand can be used with explain() method to provide a detailed execution plan of a query and provide insight into the query performance.
Reference:
https://docs.aws.amazon.com/documentdb/latest/developerguide/user_diagnostics.html#user_diagnostics-query_plan