DEA-C01 Data Ingestion and Transformation Practice Question
A company is running a critical application that generates millions of small JSON files every hour in an S3 bucket. A data engineer needs to process these files in near real-time using AWS Glue. The engineer wants to minimize the latency between file arrival and Glue job start. Which TWO actions should the engineer take?
⚠ Common exam trap
Many exam-takers confuse job startup latency with job execution speed — candidates often choose DPU increases (Option B) thinking they reduce latency, but DPUs only affect processing speed after the job starts, not the time to initiate the job.
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
✓
Pre-process the files to consolidate them into larger files before the Glue job runs.
Consolidating millions of small JSON files into larger files reduces the overhead of S3 LIST operations and minimizes the number of partitions Glue must scan. This directly lowers the latency between file arrival and job start, as Glue jobs are more efficient when processing fewer, larger files rather than many small files. Option D is correct because S3 event notifications can trigger a Lambda function that immediately starts the Glue job upon file arrival, enabling near real-time processing without polling or scheduled delays.
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 Glue job's batch window to 600 seconds.
Why it's wrong here
Increasing batch window delays job start.
- ✗
Increase the number of DPUs for the Glue job to accelerate processing.
Why it's wrong here
This helps processing speed but not start latency.
- ✓
Pre-process the files to consolidate them into larger files before the Glue job runs.
Why this is correct
Fewer larger files reduce Glue job overhead and improve throughput.
- ✓
Use Amazon S3 event notifications to trigger an AWS Lambda function that starts the Glue job upon file arrival.
Why this is correct
Event-driven invocation reduces latency compared to scheduled runs.
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 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.