Question

Which of the following is true with respect to strongly consistent read requests from an application to a DynamoDB with a DAX cluster?

A. All requests are forwarded to DynamoDB & results are cached.

B. All requests are forwarded to DynamoDB & results are stored in Item Cache before passing to application.

C. All requests are forwarded to DynamoDB & results are stored in Query Cache before passing to application.

D. All requests are forwarded to DynamoDB & results are not cached.

Answer 1

DynamoDB Accelerator (DAX) is a fully managed, highly available, in-memory cache for DynamoDB that supports strongly consistent read requests. When an application sends a strongly consistent read request to a DAX cluster, DAX will forward the request to DynamoDB and cache the response. The cached data is then used to serve subsequent read requests, which can improve the application's read performance and reduce the workload on DynamoDB.

Answer: A is correct. All strongly consistent read requests are forwarded to DynamoDB and the results are cached in the DAX cluster. The cache is maintained until the item is updated or deleted, or until the cache is evicted due to memory constraints.

Answer B is incorrect because the results are not stored in the Item Cache. The Item Cache is a separate cache that is used to cache individual items, rather than query results.

Answer C is incorrect because the results are not stored in the Query Cache. The Query Cache is a separate cache that is used to cache the results of specific queries, rather than all strongly consistent read requests.

Answer D is incorrect because the results are cached in the DAX cluster. DAX is specifically designed to cache the results of strongly consistent read requests, so that subsequent read requests can be served from the cache without querying DynamoDB again.