Q42 — AWS SAA-C03 Ch.2

Question 42 of 65 | ← Chapter 2

Q107. A company runs an application on a large fleet of Amazon EC2 instances. The application reads and write entries into an Amazon DynamoDB table. The size of the DynamoDB table continuously grows, but the application needs only data from the last 30 days. The company needs a solution that minimizes cost and development effort.Which solution meets these requirements?

• A. Use an AWS CloudFormation template to deploy the complete solution. Redeploy the CloudFormation stack every 30 days, and delete the original stack.
• B. Use an EC2 instance that runs a monitoring application from AWS Marketplace. Configure the monitoring application to use Amazon DynamoDB Streams to store the timestamp when a new item is created in the table. Use a script that runs on the EC2 instance to delete items that have a timestamp that is older than 30 days
• C. Configure Amazon DynamoDB Streams to invoke an AWS Lambda function when a new item is created in the table.Configure the Lambda function to delete items in the table that are older than 30 days
• D. Extend the application to add an attribute that has a value of the current timestamp plus 30 days to each new item that is created in the table. Configure DynamoDB to use the attribute as the TTL attribute. ✓

Correct Answer: D. Extend the application to add an attribute that has a value of the current timestamp plus 30 days to each new item that is created in the table. Configure DynamoDB to use the attribute as the TTL attribute.

Explanation

D is correct. Amazon DynamoDB Time to Live (TTL) allows you to define a per-item timestamp to determine when an item is no longer needed. Shortly after the date and time of the specified timestamp, DynamoDB deletes the item from your table without consuming any write throughput. TTL is provided at no extra cost as a means to reduce stored data volumes by retaining only the items that remain current for your workload's needs.TTL is useful if you store items that lose relevance after a specific time. The following are example TTL use cases:Remove user or sensor data after one year of inactivity in an application. Archive expired items to an Amazon S3 data lake via Amazon DynamoDB Streams and AWS Lambda. Retain sensitive data for a certain amount of time according to contractual or regulatory obligations. https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/TTL.html