In order to optimize the cost and performance of a DynamoDB table, a database specialist would like to identify frequently accessed keys. What service can the specialist use to achieve this in the most optimal way?

Answer options:

A.Performance Insights
B.CloudWatch Contributor Insights
C.CloudTrail Events
D.AWS X-Ray

Answer: B
Option A is incorrect because Performance Insights is a service specific to Amazon RDS.
Option B is CORRECT because CloudWatch Contributor Insights is a service for analyzing log data and identifying top contributors influencing system performance. It can be used to determine frequently accessed attribute keys of DynamoDB tables.
Option C is incorrect because CloudTrail is a log of AWS services API activity. It cannot be used for monitoring and analyzing the performance of DynamoDB tables.
Option D is incorrect because AWS X-Ray is used for debugging and tracing requests in microservices applications. Although it does provide some performance data of the request traces (e.g., request latency), its capability for easy statistical analysis of DynamoDB database performance is limited as it is not purpose-built for that use case. Further, the use of X-Ray requires application code change. Therefore, this is not an ideal solution.
Reference:
https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/contributorinsights_HowItWorks.html