DEA-C01 Data Ingestion and Transformation Practice Question
A data engineering team needs to transform CSV files to Parquet format after they land in an S3 bucket. The transformation should be triggered automatically as soon as a new file arrives. Which AWS service is best suited for this task?
⚠ Common exam trap
Many candidates choose AWS Glue (Option D) because it is a dedicated ETL service, but they overlook the requirement for immediate, event-driven processing, which Glue's scheduled jobs cannot provide without additional event-bridge triggers.
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
✓
AWS Lambda function triggered by S3 event
AWS Lambda functions can be directly triggered by S3 events (e.g., `s3:ObjectCreated:*`) to process newly uploaded CSV files. This serverless approach provides near-instantaneous, event-driven transformation to Parquet without managing any infrastructure, making it the most cost-effective and simplest solution for this specific use case.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
AWS Batch job submitted by S3 event
Why it's wrong here
AWS Batch has higher startup latency compared to Lambda.
- ✗
Amazon EMR cluster running continuously
Why it's wrong here
Running a persistent cluster is costly and inefficient for sporadic file arrivals.
- ✓
AWS Lambda function triggered by S3 event
Why this is correct
Lambda can be triggered immediately on S3 PUT events and perform the transformation.
- ✗
AWS Glue ETL job scheduled every 5 minutes
Why it's wrong here
Scheduled jobs introduce latency; Lambda provides near real-time trigger.
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.