One of your clients has a web application hosted on-prem and has recently migrated its database service to DynamoDB. The application receives more than 1000 read requests per second compared to 200 write requests every second. The client has asked you to implement a caching mechanism to speed up the read requests and save costs on RCUs. What changes are needed to make it work?

Answer options:

A.Create an ElastiCache redis cluster and configure your application to write the most frequently accessed data to redis for faster read queries.
B.Place DynamoDB accelerator in front of the database to cache frequently accessed data.
C.Place an ElastiCache Memcached cluster in front of DynamoDB to cache the requests.
D.None of the above.

Correct Answer: B
DAX (DynamoDB Accelerator is a dedicated service designed to cache DynamoDB requests. It will automatically add the data in DAX if there’s a cache miss or update the data if it is updated in the table).
A is incorrect: You can implement the ElastiCache redis cluster. But that will require additional overhead compared to DAX. You will have to manually write data to redis cluster in case of a cache miss and update the data in the cluster in case of data update in DynamoDB. DAX is a better option compared to ElastiCache hence this is an invalid choice.
C is incorrect: The same applies with Memcached cluster as well. Additional overhead like redis cluster.
D is incorrect: Because option B is the correct answer, this is an invalid choice.
Reference: https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/DAX.html