DEA-C01 Data Ingestion and Transformation Practice Question
A data engineer is using AWS Glue Studio to build a job that reads from an Amazon S3 bucket containing nested JSON, flattens arrays using Relationalize, and writes Parquet to another S3 bucket. The job must run only when new objects land in the source bucket. The engineer wants to avoid unnecessary job runs and minimize cost. Which approach should the engineer use?
⚠ Common exam trap
The trap here is choosing a scheduled cron trigger with bookmarks, which still launches the job on every interval even when no new objects exist.
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 an Amazon EventBridge rule that matches S3 Object Created events on the source prefix and targets the Glue job as the rule's target.
S3 can emit Object Created events that EventBridge matches by bucket and prefix, and EventBridge supports an AWS Glue job as a direct target. This is the canonical event-driven pattern: the job starts only when a new object lands, eliminating idle scheduled runs. Polling and SNS notifications either add latency or require manual steps, and a fixed cron schedule still burns DPUs on empty runs.
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 an Amazon EventBridge rule that matches S3 Object Created events on the source prefix and targets the Glue job as the rule's target.
Why this is correct
EventBridge can match S3 Object Created events filtered by bucket and key prefix, then invoke a Glue job directly as a target. This event-driven pattern starts the job exactly when new objects arrive, avoids idle scheduled runs, and reduces cost while meeting the requirement to run only on new data.
- ✗
Create an AWS Lambda function that polls the S3 bucket using the ListObjectsV2 API on a one-minute schedule and starts the Glue job when new keys appear.
Why it's wrong here
Polling with ListObjectsV2 on a one-minute schedule introduces latency, requires custom state tracking to remember which keys were seen, and can miss or duplicate events under concurrency. It is more complex and less reliable than native event delivery, and it still runs on a fixed cadence rather than reacting to arrivals.
- ✗
Schedule the Glue job with a cron trigger every five minutes and rely on Glue job bookmarks to skip already-processed files.
Why it's wrong here
A five-minute cron trigger still launches the job on schedule regardless of whether new data exists, wasting DPU time on empty runs. Job bookmarks skip reprocessing but do not prevent the job from starting. This design incurs unnecessary cost and does not satisfy the requirement to run only when new objects arrive.
- ✗
Enable S3 Event Notifications to publish to an Amazon SNS topic and subscribe the data engineer's email address to the topic.
Why it's wrong here
SNS notifications would email the engineer when objects land, but they do not start the Glue job automatically. The pipeline would require manual intervention, which does not satisfy the automation requirement. SNS can be part of a fan-out design, but by itself it is only a notification mechanism, not a job 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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Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official Amazon Web Services exam blueprint
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.