The correct answer is to configure a dead-letter queue (DLQ) on the SQS queue and set the Lambda function’s reserved concurrency to 1. This combination directly addresses both requirements: the DLQ captures any messages that exhaust their retry attempts due to transient downstream failures, preserving them for later analysis or reprocessing, while setting reserved concurrency to 1 throttles the Lambda function to a single concurrent execution, which naturally paces the rate of downstream calls and prevents overwhelming the service. On the AWS Certified DevOps Engineer Professional DOP-C02 exam, this scenario tests your understanding of how SQS redrive policies interact with Lambda concurrency limits to build resilient, self-throttling architectures. A common trap is assuming you need to increase concurrency for faster processing, but the goal here is to reduce downstream load, not speed it up. Memory tip: think “One Lane, One Lifeboat”—reserved concurrency of 1 creates a single processing lane, and the DLQ is the lifeboat that saves failed messages for later.
DOP-C02 Resilient Cloud Solutions Practice Question
This DOP-C02 practice question tests your understanding of resilient cloud solutions. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A company uses AWS Lambda functions to process events from an Amazon SQS queue. The Lambda function occasionally fails due to a transient downstream service error. The DevOps team wants to ensure that failed messages are not lost and can be retried later. The team also wants to reduce the number of invocations on the downstream service. Which configuration should the team use?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Configure a dead-letter queue (DLQ) on the SQS queue and set the Lambda function's reserved concurrency to 1.
Option A is correct because configuring a dead-letter queue (DLQ) on the SQS queue ensures that messages that exhaust their retries (due to Lambda failures) are preserved for later reprocessing, preventing data loss. Setting the Lambda function's reserved concurrency to 1 throttles the function to a single concurrent invocation, which naturally reduces the rate of downstream service calls and allows the SQS queue's visibility timeout and redrive policy to manage retry timing, thereby reducing pressure on the downstream service.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✓
Configure a dead-letter queue (DLQ) on the SQS queue and set the Lambda function's reserved concurrency to 1.
Read the scenario before looking for a memorised answer.
✗
Configure an Amazon SNS topic as a Lambda destination for failure events and subscribe the SQS queue to it.
Why it's wrong here
Lambda destinations are for async invocations; not for SQS-triggered.
✗
Configure a dead-letter queue (DLQ) on the Lambda function and set the function's maximum retry attempts to 2.
Why it's wrong here
Lambda DLQ is for async invocations; SQS event source uses its own DLQ.
✗
Configure the Lambda function to write failed messages to an Amazon DynamoDB table and set up a scheduled Lambda to retry.
Why it's wrong here
Overly complex; DLQ is simpler.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often confuse a Lambda function's DLQ (which captures invocation records) with an SQS queue's DLQ (which captures the original messages), and they overlook that reserved concurrency is a direct way to throttle invocation rate, not just a capacity planning tool.
Detailed technical explanation
How to think about this question
When an SQS queue triggers a Lambda function with reserved concurrency set to 1, Lambda will only process one message at a time; additional messages remain in the queue and become visible again after the visibility timeout, effectively acting as a built-in backoff. The SQS DLQ captures messages after the maxReceiveCount is exceeded (e.g., 3 retries), ensuring no message is lost while the downstream service is protected from a flood of retries. This pattern is often used in event-driven architectures where the downstream service has strict rate limits or is prone to transient failures.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
TExam Day Tips
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A startup's cloud architect reviews their monthly bill and notices costs are higher than expected for a long-running batch job. Switching from on-demand instances to Reserved Instances — or using Spot/Preemptible VMs — can reduce compute costs by up to 72 %. Questions like this test whether you understand the tradeoffs between commitment, flexibility, and cost across cloud pricing models.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Resilient Cloud Solutions — This question tests Resilient Cloud Solutions — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Configure a dead-letter queue (DLQ) on the SQS queue and set the Lambda function's reserved concurrency to 1. — Option A is correct because configuring a dead-letter queue (DLQ) on the SQS queue ensures that messages that exhaust their retries (due to Lambda failures) are preserved for later reprocessing, preventing data loss. Setting the Lambda function's reserved concurrency to 1 throttles the function to a single concurrent invocation, which naturally reduces the rate of downstream service calls and allows the SQS queue's visibility timeout and redrive policy to manage retry timing, thereby reducing pressure on the downstream service.
What should I do if I get this DOP-C02 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. A company uses AWS Lambda functions to process events from Amazon SQS. The Lambda function sometimes fails due to timeouts. The team wants to preserve the event for reprocessing. How should they configure the integration?
hard
✓ A.Set up a DLQ on the SQS queue that receives the events
B.Use Lambda reserved concurrency
C.Enable Lambda function DLQ with SNS topic
D.Increase Lambda timeout to maximum
Why A: By configuring a dead-letter queue (DLQ) on the SQS queue, failed messages are preserved for later reprocessing.
Variation 2. A company uses AWS Lambda to process messages from an Amazon SQS queue. The Lambda function occasionally times out after 15 seconds. To improve resilience, the team wants to ensure messages are not lost and are retried. Which configuration is MOST appropriate?
medium
A.Reduce the Lambda timeout to 5 seconds to fail fast and retry quickly.
B.Set the SQS queue visibility timeout to less than the Lambda timeout.
C.Increase the batch size and remove the DLQ to speed up processing.
✓ D.Increase the Lambda timeout to 30 seconds and configure a dead-letter queue (DLQ) for the SQS queue.
Why D: Option B is correct because increasing the visibility timeout to allow Lambda to process and leveraging dead-letter queue for failed messages ensures no messages are lost. Option A is wrong because reducing timeout worsens the issue. Option C is wrong because removing the DLQ loses failed messages. Option D is wrong because batching does not help with timeout.
Last reviewed: Jun 24, 2026
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
This DOP-C02 practice question is part of Courseiva's free Amazon Web Services certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the DOP-C02 exam.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.