DEA-C01 Data Store Management Practice Question
A company is designing a data lake on Amazon S3. Which TWO strategies improve query performance for Amazon Athena?
⚠ Common exam trap
Test-takers frequently confuse data management features (like versioning or encryption) with performance optimizations, or assume that simpler formats like CSV are sufficient for analytics, ignoring the significant performance benefits of partitioning and columnar storage.
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
✓
Partition the data by frequently queried columns such as date or region.
Partitioning data by frequently queried columns (e.g., date or region) allows Athena to prune the data scanned by only reading the relevant partitions, reducing the amount of data scanned and improving query performance. This is a core optimization for Athena, which charges based on data scanned and performs better with less I/O.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Enable S3 Versioning on the bucket.
Why it's wrong here
Versioning adds overhead and does not improve query performance.
- ✗
Use server-side encryption with AWS KMS (SSE-KMS).
Why it's wrong here
Encryption does not improve query performance.
- ✓
Partition the data by frequently queried columns such as date or region.
Why this is correct
Partitioning prunes the data scanned.
- ✓
Use columnar file formats like Parquet or ORC.
Why this is correct
Columnar formats reduce data scanned.
- ✗
Store data in CSV format with header rows.
Why it's wrong here
CSV is not as efficient as columnar formats.
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.