DEA-C01 Data Store Management Practice Question
A data engineer is building a data lake on Amazon S3 and needs to store JSON logs that will be queried by Amazon Athena. The engineer wants to minimize query cost and improve performance by reducing the amount of data scanned. The logs are approximately 1 KB each and arrive continuously. Which solution should the engineer implement?
⚠ Common exam trap
The trap here is assuming that changing the S3 storage class reduces Athena query costs, when Athena cost is driven by data scanned, not by where the data is stored.
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
✓
Convert the JSON logs to Apache Parquet, partition the data by date, and store it in Amazon S3. Query with Athena.
Athena charges based on the amount of data scanned per query. Converting JSON to a columnar format like Parquet allows column pruning, so only the needed columns are read, and partitioning by date enables partition pruning, so only relevant folders are scanned. This combination minimizes data scanned, reducing cost and improving query speed.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Convert the JSON logs to Apache Parquet, partition the data by date, and store it in Amazon S3. Query with Athena.
Why this is correct
Converting to columnar Parquet enables Athena to read only the columns referenced in a query, and partitioning by date allows Athena to skip irrelevant partitions. Together, these reduce the amount of data scanned, lowering query cost and improving performance, which directly meets the requirement.
- ✗
Store the JSON logs in Amazon S3 Standard-Infrequent Access (S3 Standard-IA) and query them with Athena.
Why it's wrong here
S3 Standard-IA reduces storage costs for infrequently accessed data, but it does not reduce the amount of data scanned by Athena. Athena scans all objects in the queried prefix regardless of storage class, so this choice does not address the requirement to minimize query cost or improve performance through reduced scanning.
- ✗
Enable S3 Transfer Acceleration on the bucket and query the JSON logs with Athena.
Why it's wrong here
S3 Transfer Acceleration speeds up uploads and downloads over long distances by using AWS edge locations. It has no effect on how Athena reads and scans data. The amount of data scanned during a query remains unchanged, so query cost and performance are not improved by this feature.
- ✗
Store the JSON logs in Amazon S3 Glacier Instant Retrieval and query them with Athena.
Why it's wrong here
S3 Glacier Instant Retrieval is an archival storage class intended for long-term retention with infrequent access. While it offers low-cost storage, Athena queries against Glacier objects incur retrieval charges and are not optimized for frequent analytical queries. It also does not reduce the volume of data scanned during queries.
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
Related to this question
About these practice questions
Courseiva writes every DEA-C01 question from scratch — 1,321 in total, each with an explanation and a wrong-answer breakdown. None are copied from real exams or dumps. Learn why practice questions differ from exam dumps →
JA
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.