AWS Certified Developer – Associate (DVA-C02) — Question 322

A company is releasing a new feature. Users can request early access to the new feature by using an application form. The company expects a surge of requests when the application form becomes available. Each request will be stored as an item in an Amazon DynamoDB table.

Each item will contain the user's username, the submission date, and a validation status of UNVALIDATED. VALID, or NOT VALID. Each item also will contain the user's rating of the process on a scale of 1 to 5.

Each user can submit one request. For the DynamoDB table, the developer must choose a partition key that will give the workload well-distributed records across partitions.

Which DynamoDB attribute will meet these requirements?

Answer options

• A. Username
• B. Submission date
• C. Validation status
• D. Rating of the process on a scale of 1 to 5

Correct answer: A

Explanation

A partition key in Amazon DynamoDB should have high cardinality to ensure well-distributed write and read requests across multiple partitions. The username is unique for each request and has high cardinality, making it the ideal partition key. Other attributes like validation status, submission date, or rating have a limited number of distinct values, which would concentrate traffic and cause a 'hot partition' issue.