AWS Certified Solutions Architect – Associate (SAA-C02) — Question 772

A solutions architect is designing a multi-tier application for a company. The application's users upload images from a mobile device. The application generates a thumbnail of each image and returns a message to the user to confirm that the image was uploaded successfully.
The thumbnail generation can take up to 60 seconds, but the company wants to provide a faster response time to its users to notify them that the original image was received. The solutions architect must design the application to asynchronously dispatch requests to the different application tiers.
What should the solutions architect do to meet these requirements?

Answer options

• A. Write a custom AWS Lambda function to generate the thumbnail and alert the user. Use the image upload process as an event source to invoke the Lambda function.
• B. Create an AWS Step Functions workflow. Configure Step Functions to handle the orchestration between the application tiers and alert the user when thumbnail generation is complete.
• C. Create an Amazon Simple Queue Service (Amazon SQS) message queue. As images are uploaded, place a message on the SQS queue for thumbnail generation. Alert the through an application message that the image was received.
• D. Create Amazon Simple Notification Service (Amazon SNS) notification topics and subscriptions. Use one subscription with the application to generate the thumbnail after the image upload is complete. Use a second subscription to message the user's mobile app by way of a push notification after thumbnail generation is complete.

Correct answer: C

Explanation

Using Amazon SQS decouples the image upload tier from the processing tier, allowing the application to immediately acknowledge receipt of the upload to the user while the thumbnail is generated asynchronously. Options A, B, and D fail to separate the immediate acknowledgment from the 60-second thumbnail generation process, resulting in slower response times for the initial upload confirmation.