AWS Certified Developer – Associate — Question 308

A developer has built an AWS Lambda function to update a legacy system. The developer has set the Lambda function’s trigger type to Amazon EventBridge.

The legacy system was overwhelmed after the initial deployment of the Lambda function. The root cause was too many requests to the legacy system at the same time. The developer needs to limit the number of requests to the legacy system and must maintain high throughput.

Which solution will meet these requirements without requiring architecture changes?

Answer options

• A. Configure provisioned concurrency for the Lambda function. Set the provisioned concurrency to the desired number of maximum simultaneous function calls.
• B. Create an Amazon Simple Queue Service (Amazon SQS) FIFO queue. Configure the SQS queue to invoke the Lambda function. Update the EventBridge rule to target the SQS queue.
• C. Configure reserved concurrency for the Lambda function. Increase the number of asynchronous invocation retry attempts and the maximum event age for the Lambda function.
• D. Create an Amazon Simple Queue Service (Amazon SQS) standard queue. Configure the SQS queue to invoke the Lambda function. Update the EventBridge rule to target the SQS queue. Configure reserved concurrency for the Lambda function.

Correct answer: C

Explanation

Configuring reserved concurrency restricts the maximum number of concurrent executions of the Lambda function, successfully throttling requests to the legacy system without requiring architectural modifications like SQS. Since EventBridge triggers Lambda asynchronously, adjusting the retry attempts and maximum event age ensures that throttled events are eventually processed rather than lost, preserving high throughput. Options B and D are incorrect because they introduce SQS queues, which represent architectural changes.