AWS Certified Developer – Associate (DVA-C02) — Question 423

A developer is creating a database of products. Queries for frequently accessed products must have retrieval times of microseconds. To ensure data consistency, the application cache must be updated whenever products are added, changed, or deleted.

Which solution will meet these requirements?

Answer options

• A. Set up an Amazon DynamoDB database and a DynamoDB Accelerator (DAX) cluster.
• B. Set up an Amazon RDS database and an Amazon ElastiCache for Redis cluster. Implement a lazy loading caching strategy with ElastiCache.
• C. Setup an Amazon DynamoDB database that has an in-memory cache. Implement a lazy loading caching strategy in the application.
• D. Set up an Amazon RDS database and an Amazon DynamoDB Accelerator (DAX) cluster. Specify a TTL setting for the DAX cluster.

Correct answer: A

Explanation

Amazon DynamoDB Accelerator (DAX) delivers microsecond response times and automatically updates its cache during write operations, ensuring immediate data consistency. Lazy loading strategies can lead to stale data because the cache is only updated after a cache miss, which does not meet the requirement of updating the cache whenever products are modified. Additionally, DAX is a specialized cache designed exclusively for DynamoDB and cannot be paired with Amazon RDS.