AWS Certified Solutions Architect – Associate (SAA-C02) — Question 321

A company is using Amazon DynamoDB with provisioned throughput for the database tier of its ecommerce website. During flash sales, customers experience periods of time when the database cannot handle the high number of transactions taking place. This causes the company to lose transactions. During normal periods, the database performs appropriately.
Which solution solves the performance problem the company faces?

Answer options

• A. Switch DynamoDB to on-demand mode during flash sales.
• B. Implement DynamoDB Accelerator for fast in memory performance.
• C. Use Amazon Kinesis to queue transactions for processing to DynamoDB.
• D. Use Amazon Simple Queue Service (Amazon SQS) to queue transactions to DynamoDB.

Correct answer: A

Explanation

Switching Amazon DynamoDB to on-demand capacity mode allows the database to instantly scale up to accommodate unpredictable spikes in traffic, such as during flash sales, without needing to manually pre-provision throughput. While Amazon SQS or Amazon Kinesis could queue transactions, they introduce write-latency and architectural complexity rather than scaling the database itself to handle the direct load. DynamoDB Accelerator (DAX) is an in-memory cache designed to improve read performance, which does not resolve write throttling issues during transactional spikes.