AWS Certified Developer – Associate (DVA-C02) — Question 175

A company is building an application for stock trading. The application needs sub-millisecond latency for processing trade requests. The company uses Amazon DynamoDB to store all the trading data that is used to process each trading request.

A development team performs load testing on the application and finds that the data retrieval time is higher than expected. The development team needs a solution that reduces the data retrieval time with the least possible effort.

Which solution meets these requirements?

Answer options

• A. Add local secondary indexes (LSIs) for the trading data.
• B. Store the trading data in Amazon S3, and use S3 Transfer Acceleration.
• C. Add retries with exponential backoff for DynamoDB queries.
• D. Use DynamoDB Accelerator (DAX) to cache the trading data.

Correct answer: D

Explanation

The correct answer is D because DynamoDB Accelerator (DAX) provides in-memory caching, significantly speeding up data retrieval and achieving the sub-millisecond latency required. Options A, B, and C do not address the need for reduced latency as effectively as DAX does; LSIs require additional write operations, S3 is not suited for low-latency access, and retries with exponential backoff may still result in increased latency.