MLS-C01 Data Engineering Practice Question
A data engineer is designing a data pipeline that uses Amazon S3 events to trigger an AWS Lambda function for processing. The pipeline must handle high throughput with low latency. Which TWO configurations should be applied?
⚠ Common exam trap
Watch out — candidates often confuse 'reducing latency' with 'using a VPC' or 'adding a queue,' but for S3-triggered Lambda, direct invocation with reserved concurrency is the simplest and lowest-latency path, while VPCs and queues add overhead.
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 Lambda with reserved concurrency
Reserved concurrency ensures that the Lambda function always has a guaranteed number of concurrent executions available, preventing it from being throttled by other functions in the same AWS account. This is critical for high-throughput, low-latency pipelines because S3 event notifications can burst many invocations simultaneously, and without reserved concurrency, the function might hit the account-level concurrency limit and drop events.
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 Lambda with reserved concurrency
Why this is correct
Ensures Lambda has enough capacity to handle bursts.
- ✗
Use an SQS queue between S3 and Lambda
Why it's wrong here
Adds latency and complexity.
- ✗
Place Lambda in a VPC to reduce network latency
Why it's wrong here
VPC adds latency due to ENI creation; not beneficial here.
- ✗
Use Amazon Kinesis Data Streams as an intermediary
Why it's wrong here
Not needed for S3 event triggers.
- ✓
Enable S3 Event Notifications to invoke Lambda directly
Why this is correct
Direct invocation provides low latency.
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 |
Go deeper
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This MLS-C01 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 MLS-C01 exam.