SOA-C02 Cost and Performance Optimization Practice Question
A SysOps administrator notices that a Lambda function is timing out after 30 seconds. The function processes large files from S3. How can the administrator improve performance while minimizing cost?
⚠ Common exam trap
Many exam-takers assume increasing the timeout is the only way to fix a timeout error, overlooking that Lambda's memory setting controls CPU allocation and can actually speed up execution to stay within the original timeout.
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
✓
Increase the memory allocation of the Lambda function.
Increasing the memory allocation of the Lambda function also proportionally increases the allocated CPU power, which directly reduces the execution time for CPU-bound tasks like processing large files. This often resolves timeout issues without incurring additional cost per invocation, as the cost is a product of memory and duration, and a faster execution can offset the higher memory price.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Increase the timeout value to 5 minutes.
Why it's wrong here
Raising the timeout to 5 minutes merely lets the function run longer before failing; it does not reduce the actual execution time or improve the underlying performance problem. If the function is taking too long because of insufficient CPU or memory, it will likely time out again even with a larger timeout. Additionally, Lambda billing is duration-based, so allowing a slow function to run longer increases cost without fixing the root cause.
- ✗
Enable Provisioned Concurrency.
Why it's wrong here
Provisioned Concurrency pre-warms execution environments to eliminate cold-start latency, but it does nothing to speed up the code once the function is actually invoked. If the function is already warm and still exceeding its current timeout, the bottleneck is execution performance, not initialization overhead. Adding Provisioned Concurrency would increase costs and complexity without addressing the CPU or memory insufficiency causing the slowness.
- ✓
Increase the memory allocation of the Lambda function.
Why this is correct
Lambda allocates CPU power in direct proportion to the memory configuration, so increasing memory gives the function more compute capacity to execute faster. For CPU-bound or memory-intensive workloads, this can dramatically reduce execution time and prevent timeouts. Since Lambda billing is based on compute time, a shorter duration may actually lower overall cost, making memory tuning the primary lever for performance optimization.
- ✗
Deploy the function on an EC2 instance.
Why it's wrong here
Migrating the function to EC2 abandons the serverless model and introduces significant operational burden: you must manage patching, scaling, and high availability. It does not directly fix the inefficient execution or resource starvation that is causing the timeout. For most workloads, EC2 would be more expensive and slower to iterate on, whereas simply increasing Lambda memory would resolve the performance issue with minimal effort.
Visual reference
Quick reference
AWS S3 Storage Class Comparison
| Storage Class | Min Duration | Retrieval | Use Case |
|---|---|---|---|
| S3 Standard | None | Immediate | Frequently accessed data |
| S3 Standard-IA | 30 days | Immediate | Infrequent access, rapid retrieval |
| S3 One Zone-IA | 30 days | Immediate | Non-critical infrequent data |
| S3 Intelligent-Tiering | None | Immediate–hours | Unknown or changing access patterns |
| S3 Glacier Instant | 90 days | Milliseconds | Archive with instant retrieval |
| S3 Glacier Flexible | 90 days | Minutes–hours | Archive, flexible retrieval |
| S3 Glacier Deep Archive | 180 days | Hours | Long-term compliance archive |
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This SOA-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 SOA-C02 exam.