AWS Certified Solutions Architect – Associate (SAA-C02) — Question 680

The customers of a finance company request appointments with financial advisors by sending text messages. A web application that runs on Amazon EC2 instances accepts the appointment requests. The text messages are published to an Amazon Simple Queue Service (Amazon SQS) queue through the web application. Another application that runs on EC2 instances then sends meeting invitations and meeting confirmation email messages to the customers. After successful scheduling, this application stores the meeting information in an Amazon DynamoDB database.
As the company expands, customers report that their meeting invitations are taking longer to arrive.
What should a solutions architect recommend to resolve this issue?

Answer options

• A. Add a DynamoDB Accelerator (DAX) cluster in front of the DynamoDB database.
• B. Add an Amazon API Gateway API in front of the web application that accepts the appointment requests.
• C. Add an Amazon CloudFront distribution. Set the origin as the web application that accepts the appointment requests.
• D. Add an Auto Scaling group for the application that sends meeting invitations. Configure the Auto Scaling group to scale based on the depth of the SQS queue.

Correct answer: D

Explanation

The bottleneck occurs because the EC2 instances processing the SQS queue cannot keep up with the increased volume of incoming messages. Implementing an Auto Scaling group that scales based on SQS queue depth ensures that more instances are provisioned to handle spikes in message volume, resolving the processing delay. Options A, B, and C address database reads, API management, and content delivery respectively, none of which resolve the queue processing bottleneck.