AWS Certified Solutions Architect – Associate (SAA-C03) — Question 636

A company runs a web application on Amazon EC2 instances in an Auto Scaling group. The application uses a database that runs on an Amazon RDS for PostgreSQL DB instance. The application performs slowly when traffic increases. The database experiences a heavy read load during periods of high traffic.

Which actions should a solutions architect take to resolve these performance issues? (Choose two.)

Answer options

• A. Turn on auto scaling for the DB instance.
• B. Create a read replica for the DB instance. Configure the application to send read traffic to the read replica.
• C. Convert the DB instance to a Multi-AZ DB instance deployment. Configure the application to send read traffic to the standby DB instance.
• D. Create an Amazon ElastiCache cluster. Configure the application to cache query results in the ElastiCache cluster.
• E. Configure the Auto Scaling group subnets to ensure that the EC2 instances are provisioned in the same Availability Zone as the DB instance.

Correct answer: B, D

Explanation

To mitigate heavy read loads on an Amazon RDS DB instance, creating a read replica (Option B) allows offloading read queries from the primary database. Implementing an Amazon ElastiCache cluster (Option D) further improves performance by caching frequent query results, reducing the overall database load. Multi-AZ standby instances (Option C) are for disaster recovery and cannot accept read traffic, while storage auto scaling (Option A) handles storage capacity, not read performance.