AWS Certified Solutions Architect – Associate (SAA-C03) — Question 378

An ecommerce company is running a multi-tier application on AWS. The front-end and backend tiers both run on Amazon EC2, and the database runs on Amazon RDS for MySQL. The backend tier communicates with the RDS instance. There are frequent calls to return identical datasets from the database that are causing performance slowdowns.

Which action should be taken to improve the performance of the backend?

Answer options

• A. Implement Amazon SNS to store the database calls.
• B. Implement Amazon ElastiCache to cache the large datasets.
• C. Implement an RDS for MySQL read replica to cache database calls.
• D. Implement Amazon Kinesis Data Firehose to stream the calls to the database.

Correct answer: B

Explanation

Implementing Amazon ElastiCache allows the application to store frequently accessed query results in memory, drastically reducing the latency of identical database calls and offloading traffic from Amazon RDS. Amazon SNS is a pub/sub messaging service and cannot cache data, while Amazon Kinesis Data Firehose is used for streaming data delivery and does not address database query caching. While RDS read replicas can help scale read traffic, they do not cache query results in memory like ElastiCache does to deliver sub-millisecond response times.