Your company has developed a Serverless web and mobile application that allows users to upload and monetize video courses. The application uses the API Gateway and Lambda as the front-end stack and uses MongoDB as the database. All the video contents are stored in the S3 and served via the CloudFront. The MongoDB is hosted outside of the AWS environment as a 3rd party database service. After the initial launch, the company started receiving performance-related issues for some of its popular courses.

Answer options:

A.Use the DynamoDB instead of MongoDB as it provides better scalability and performance.
B.Migrate the MongoDB from outside of the AWS to inside the AWS. This will reduce the additional latency required to connect with the database from the AWS environment.
C.Integrate the AWS X-Ray and create a segment around the MongoDB connections to measure actual latency per request.
D.Use ElastiCache to cache the popular or frequently used courses data to reduce the interaction with the database.
E.Use the AWS SQS in front of the database connection to decouple the application with direct database connectivity.

Correct Answers: B, C, and D
Option A is INCORRECT because while DynamoDB does provide better scalability and performance, it would need significant changes into the current application and would not be the right fit.
Option B is CORRECT because this will surely reduce the additional latency overhead by using the MongoDB over the public interface to migrate to inside the AWS and use the high-speed private channels.
Option C is CORRECT because the X-Ray can start logging the requests being made from one component to another and reporting the application`s overall performance. With the use of segments and annotations, the requests can be further refined.
Option D is CORRECT because this will speed up the overall response. Instead of fetching the course data from the database every time, the frequent access records can be cached and served from the caching server.
Option E is INCORRECT because putting the SQS in-front of the database will not have any performance impact nor fulfill any application purpose. The SQS in-front of the database is generally used to reduce the request overhead onto the database and update the database consistently.