DVA-C02 Question #310: Real Exam Question with Answer & Explanation

Question

A developer created an AWS Lambda function that performs a series of operations that involve multiple AWS services. The function's duration time is higher than normal. To determine the cause of the issue, the developer must investigate traffic between the services without changing the function code. Which solution will meet these requirements?

Options

• AEnable AWS X-Ray active tracing in the Lambda function. Review the logs in X-Ray.
• BConfigure AWS CloudTrail. View the trail logs that are associated with the Lambda function.
• CReview the AWS Config logs in Amazon CloudWatch.
• DReview the Amazon CloudWatch logs that are associated with the Lambda function.

Explanation

Option A is correct because AWS X-Ray active tracing provides distributed tracing that automatically instruments Lambda and all downstream AWS service calls, giving you a visual service map and detailed timing breakdown of each operation - all without modifying your function code.

Why the others are wrong:

• B (CloudTrail) records API management calls (who did what to your AWS resources), not the performance or traffic flow between services during function execution.
• C (AWS Config logs) tracks configuration changes to AWS resources over time - it's a compliance/auditing tool, not a performance debugging tool.
• D (CloudWatch logs) shows standard Lambda logs (console.log output), but only reveals what the developer explicitly logged; it won't show inter-service traffic timing without code changes.

Memory tip: Think of X-Ray as an "X-ray machine" - it sees through your distributed application to show exactly how traffic flows between services and where time is being spent, with zero code changes required when active tracing is enabled.

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