DEA-C01 Data Ingestion and Transformation Practice Question
A company wants to use AWS Glue to transform data stored in Amazon S3. The data is partitioned by date and includes both CSV and Parquet files. The transformation should be optimized for cost and performance. Which THREE actions should the data engineer take? (Choose THREE.)
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 partition pruning by filtering on the date column in the ETL script.
Options B, C, and E are correct. Partition pruning (B) reduces the amount of data scanned by filtering on the date column, lowering cost and improving performance. Job bookmarks (C) track processed data, preventing reprocessing and saving time and cost. Converting files to Parquet (E) reduces data size and enhances query performance due to its columnar format. Option A is incorrect because running a crawler before each job creates unnecessary overhead; the schema can be defined once or crawled periodically. Option D is incorrect because increasing DPUs to the maximum is costly and does not optimize performance; proper data partitioning and format are more effective.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Run a crawler to update the schema before each job run.
Why it's wrong here
Unnecessary if schema is stable.
- ✓
Use partition pruning by filtering on the date column in the ETL script.
Why this is correct
Reduces data scanned.
- ✓
Use job bookmarks to process only new data.
Why this is correct
Avoids reprocessing.
- ✗
Increase the number of DPUs to the maximum allowed.
Why it's wrong here
Increases cost unnecessarily.
- ✓
Convert all files to Parquet format before processing.
Why this is correct
Parquet is more efficient.
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.