DEA-C01 Data Ingestion and Transformation Practice Question
A company uses AWS Glue crawlers to populate the Data Catalog from data in Amazon S3. The crawler fails to update the schema when new columns are added to the CSV files. What is the most likely cause?
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
✓
The crawler uses a custom classifier that defines a fixed schema.
When a crawler uses a custom classifier that defines a fixed schema, it will not recognize new columns added to the CSV files because the custom classifier overrides the schema inference. Option A is incorrect because S3 bucket versioning does not affect crawler schema updates. Option B is incorrect because the crawler configuration to crawl new partitions does not prevent schema updates; it only affects which partitions are crawled. Option C is incorrect because the IAM role would cause permissions errors, not a failure to update schema due to new columns.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
The S3 bucket has versioning enabled.
Why it's wrong here
Versioning does not affect crawler behavior.
- ✗
The crawler is configured to only crawl new partitions.
Why it's wrong here
Partition discovery does not affect schema update.
- ✗
The IAM role for the crawler lacks permissions to read the new columns.
Why it's wrong here
Permissions would cause access errors, not ignored columns.
- ✓
The crawler uses a custom classifier that defines a fixed schema.
Why this is correct
Custom classifiers can override schema inference.
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 |
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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.