SAP-C02 Continuous Improvement for Existing Solutions Practice Question
A company has a critical application running on AWS Lambda that processes messages from an Amazon SQS queue. The queue occasionally receives a large backlog of messages, causing Lambda to scale up significantly and incur high costs. The company wants to optimize costs while ensuring that all messages are processed in a timely manner. Which solution should a solutions architect recommend?
⚠ Common exam trap
The trap here is thinking that limiting concurrency or increasing memory is the primary way to reduce Lambda costs, when actually batching is a more effective cost optimization for queue processing.
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 an event source for Lambda with a larger batch size and a longer maximum batching window.
By increasing the batch size and maximum batching window, Lambda can retrieve more messages per invocation and wait to accumulate a full batch, reducing the number of invocations and associated costs. This is especially effective during backlogs because Lambda can process messages in larger chunks. It maintains timely processing because the batching window is limited. Other options either do not reduce invocations or may throttle processing.
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 an event source for Lambda with a batch size of 10 and a maximum batching window of 0 seconds.
Why it's wrong here
Using a batch size of 10 with no batching window means Lambda will process messages as soon as they are available, which can lead to many concurrent invocations and higher costs. While it may reduce the number of invocations compared to batch size 1, it does not optimize for cost during backlog situations. It may still scale aggressively and incur high costs.
- ✓
Configure the SQS queue as an event source for Lambda with a larger batch size and a longer maximum batching window.
Why this is correct
Increasing the batch size and batching window allows Lambda to process more messages per invocation and wait longer to accumulate messages, reducing the number of invocations and thus cost. During a backlog, Lambda can process larger batches, improving efficiency. This optimizes cost while still processing all messages in a timely manner, as the window is bounded.
- ✗
Set the Lambda function's reserved concurrency to a low value to limit scaling.
Why it's wrong here
Limiting concurrency can reduce costs by capping the number of concurrent executions, but it may cause messages to be processed slower, potentially leading to backlog growth and delayed processing. It does not optimize the efficiency of processing; it simply throttles. This could violate the requirement to process messages in a timely manner.
- ✗
Increase the Lambda function's memory allocation to reduce execution time.
Why it's wrong here
Increasing memory can reduce execution time for compute-intensive functions, but it also increases the cost per invocation. If the function is not CPU-bound, this may not significantly reduce overall cost. It does not address the scaling behavior or the backlog processing efficiency. In fact, it could increase costs if the function is already efficient.
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 |
Go deeper
Related to this question
About these practice questions
One of 984 original SAP-C02 practice questions on Courseiva, each with a full explanation and wrong-answer analysis — not exam dumps or protected exam content. Learn why practice questions differ from exam dumps →
JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official Amazon Web Services exam blueprint
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.