SAP-C02 Design for New Solutions Practice Question
A company is designing a serverless application using AWS Lambda functions. The application processes events from an Amazon SQS queue. The company wants to ensure that the Lambda function can scale to handle a sudden increase in messages without losing any messages. The Lambda function must process each message at least once. Which configuration should the company use?
⚠ Common exam trap
Many exam-takers assume increasing the batch size or using a dead-letter queue alone prevents message loss, but they overlook the critical need for reserved concurrency to guarantee scaling capacity during sudden spikes.
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
✓
Configure the SQS queue as a Lambda event source with a reserved concurrency of 1000 for the Lambda function.
Configuring the SQS queue as a Lambda event source with a reserved concurrency of 1000 ensures that Lambda can scale up to 1000 concurrent executions to handle a sudden burst of messages. The SQS event source uses long polling and synchronously invokes Lambda, which processes messages in batches and automatically deletes them from the queue only upon successful completion, guaranteeing at-least-once processing. Reserved concurrency prevents throttling and ensures that the function has sufficient capacity to scale without losing messages.
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 the SQS queue as a Lambda event source with a reserved concurrency of 1000 for the Lambda function.
Why this is correct
Reserved concurrency ensures the function can scale, and SQS event source mapping provides at-least-once processing.
- ✗
Configure the SQS queue to invoke the Lambda function asynchronously and set the Lambda function timeout to 5 minutes.
Why it's wrong here
Lambda cannot be invoked asynchronously by SQS; it polls the queue synchronously.
- ✗
Set the SQS queue visibility timeout to 30 seconds and the Lambda batch size to 100. Configure a dead-letter queue for failed messages.
Why it's wrong here
A batch size of 100 may cause Lambda timeouts, and this configuration does not address scaling.
- ✗
Use an SQS FIFO queue with a Lambda function that has a reserved concurrency of 1.
Why it's wrong here
FIFO queues are for exactly-once processing, but throughput is limited, and a concurrency of 1 may cause backlogs.
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 |
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This SAP-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 SAP-C02 exam.