AWS Certified Database – Specialty — Question 306

A database specialist is designing an enterprise application for a large company. The application uses Amazon DynamoDB with DynamoDB Accelerator (DAX).
The database specialist observes that most of the queries are not found in the DAX cache and that they still require DynamoDB table reads.
What should the database specialist review first to improve the utility of DAX?

Answer options

• A. The DynamoDB ConsumedReadCapacityUnits metric
• B. The trust relationship to perform the DynamoDB API calls
• C. The DAX cluster's TTL setting
• D. The validity of customer-specified AWS Key Management Service (AWS KMS) keys for DAX encryption at rest

Correct answer: C

Explanation

If the DAX cluster's Time to Live (TTL) setting is configured too low, cached items will expire rapidly, resulting in frequent cache misses and forcing the application to read directly from the DynamoDB table. Reviewing the ConsumedReadCapacityUnits metric only monitors read activity but does not resolve the cache efficiency issue. IAM trust relationships and AWS KMS key validity are security and permission settings; misconfigurations here would result in access denied errors rather than successful but uncached queries.