- A
The Lambda function will be throttled due to reserved concurrency.
Why wrong: Throttling is a separate issue.
- B
The Lambda function will process messages successfully with no issues.
Why wrong: The visibility timeout is shorter than processing time.
- C
Messages will be processed multiple times because they become visible again before the function completes.
Visibility timeout expires, making messages visible again.
- D
The Lambda function will automatically increase its processing speed.
Why wrong: Lambda does not change processing speed.
Question 100 of 1,616
SQS Visibility Timeout vs Lambda Execution Time: Preventing Duplicate Messages
This DVA-C02 practice question tests your understanding of development with aws services. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. 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.
An organization has a Lambda function that processes messages from an Amazon SQS queue. The function is configured with a reserved concurrency of 5. The SQS queue has a visibility timeout of 30 seconds. The Lambda function takes an average of 45 seconds to process each message. What is the likely behavior of this setup?
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Messages will be processed multiple times because they become visible again before the function completes.
The Lambda function takes 45 seconds to process a message, but the SQS queue's visibility timeout is only 30 seconds. This means the message becomes visible again in the queue after 30 seconds, before the function has finished processing it. As a result, the message can be picked up by another consumer (or the same function in a new invocation), leading to duplicate processing. Option C correctly identifies this behavior.
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.
- ✗
The Lambda function will be throttled due to reserved concurrency.
Why it's wrong here
Throttling is a separate issue.
- ✗
The Lambda function will process messages successfully with no issues.
Why it's wrong here
The visibility timeout is shorter than processing time.
- ✓
Messages will be processed multiple times because they become visible again before the function completes.
Why this is correct
Visibility timeout expires, making messages visible again.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
The Lambda function will automatically increase its processing speed.
Why it's wrong here
Lambda does not change processing speed.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates assume Lambda automatically extends the SQS visibility timeout, but it only does so if the function completes within the original timeout; otherwise, the message becomes visible again, causing duplicate processing.
Detailed technical explanation
How to think about this question
When an SQS message is processed by Lambda, the service automatically extends the visibility timeout if the function is still running, but only if the function's execution duration is less than the visibility timeout. Here, since the function takes 45 seconds and the visibility timeout is 30 seconds, the message becomes visible again before Lambda can extend it, causing a potential duplicate. In practice, you should set the visibility timeout to at least 6 times the function's timeout (per AWS docs) or use a dead-letter queue to handle duplicates.
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.
Quick reference
Cloud Service Model Comparison
| Model | You Manage | Provider Manages | Examples |
|---|---|---|---|
| IaaS | OS, runtime, apps, data | Hardware, hypervisor, networking | EC2, Azure VMs, GCP Compute Engine |
| PaaS | Apps and data | OS, runtime, middleware, hardware | Elastic Beanstalk, Azure App Service |
| SaaS | Data and settings only | Everything else | Microsoft 365, Salesforce, Workday |
| FaaS / Serverless | Function code only | Infra, scaling, runtime | Lambda, Azure Functions, Cloud Run |
| CaaS | Containers and apps | Kubernetes, OS, hardware | EKS, AKS, GKE |
What to study next
Got this wrong? Here's your next step.
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FAQ
Questions learners often ask
What does this DVA-C02 question test?
Development with AWS Services — This question tests Development with AWS Services — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Messages will be processed multiple times because they become visible again before the function completes. — The Lambda function takes 45 seconds to process a message, but the SQS queue's visibility timeout is only 30 seconds. This means the message becomes visible again in the queue after 30 seconds, before the function has finished processing it. As a result, the message can be picked up by another consumer (or the same function in a new invocation), leading to duplicate processing. Option C correctly identifies this behavior.
What should I do if I get this DVA-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.
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Last reviewed: Jul 4, 2026
This DVA-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 DVA-C02 exam.
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