DEA-C01 Data Ingestion and Transformation Practice Question
A company uses Amazon S3 Event Notifications to trigger a Lambda function that processes incoming files. Recently, the Lambda function has been timing out for large files (>100 MB). The data engineer wants to improve the pipeline to handle large files reliably. Which solution is the MOST scalable and cost-effective?
⚠ Common exam trap
It's easy for candidates to assume increasing Lambda timeout is the simplest fix, but the DEA-C01 exam tests understanding of decoupling patterns (SQS) to handle variable workloads and avoid synchronous invocation bottlenecks.
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
✓
Use S3 Event Notification to send to an SQS queue, then have Lambda poll the queue
Decoupling S3 event notifications via an SQS queue allows Lambda to poll messages at its own pace, preventing timeouts from large files. The SQS queue acts as a buffer, enabling Lambda to process files asynchronously and scale based on the queue depth without being constrained by the synchronous S3 trigger timeout (typically 15 minutes for Lambda, but large files can still cause issues with concurrent execution limits). This approach is both scalable and cost-effective, as it avoids idle wait time and allows Lambda to process files in smaller chunks or with longer execution times as needed.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Use S3 Event Notification to send to an SQS queue, then have Lambda poll the queue
Why this is correct
SQS decouples and buffers events, allowing Lambda to process at a manageable rate.
- ✗
Use Amazon SNS to fan out the event to multiple Lambda functions
Why it's wrong here
SNS does not provide buffering; Lambda still gets concurrent invocations that may timeout.
- ✗
Use AWS Step Functions to orchestrate multiple Lambda functions for parallel processing
Why it's wrong here
Step Functions adds orchestration overhead and cost; not necessary for simple file processing.
- ✗
Increase the Lambda timeout to 15 minutes
Why it's wrong here
Lambda has a max timeout of 15 minutes, but large files may still cause timeout and does not scale.
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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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This DEA-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 DEA-C01 exam.