AWS Certified Database – Specialty — Question 142

An online advertising company is implementing an application that displays advertisements to its users. The application uses an Amazon DynamoDB table as a data store. The application also uses a DynamoDB Accelerator (DAX) cluster to cache its reads. Most of the reads are from the GetItem query and the
BatchGetItem query. Consistency of reads is not a requirement for this application.
Upon deployment, the application cache is not performing as expected. Specific strongly consistent queries that run against the DAX cluster are taking many milliseconds to respond instead of microseconds.
How can the company improve the cache behavior to increase application performance?

Answer options

• A. Increase the size of the DAX cluster.
• B. Configure DAX to be an item cache with no query cache
• C. Use eventually consistent reads instead of strongly consistent reads.
• D. Create a new DAX cluster with a higher TTL for the item cache.

Correct answer: C

Explanation

The correct answer is C because switching to eventually consistent reads will allow the application to leverage the cache more effectively, improving response times. The other options either do not address the issue of read consistency requirements or may not enhance cache performance adequately, such as increasing cluster size or modifying TTL without changing the read consistency model.