DEA-C01 Data Store Management Practice Question
A data engineer needs to store semi-structured JSON logs from multiple sources in a centralized data store for querying using SQL. The logs are immutable and need to be retained for 90 days. Which AWS service should be used?
⚠ Common exam trap
Watch out — candidates often choose DynamoDB for its JSON support and querying flexibility, overlooking that it is not designed for cost-effective long-term retention of immutable logs and lacks native SQL querying, while S3 with Athena directly addresses both requirements.
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
✓
Amazon S3 with Amazon Athena.
Amazon S3 with Amazon Athena is the correct choice because S3 provides durable, cost-effective storage for immutable semi-structured JSON logs, and Athena enables serverless SQL querying directly against the data in S3 without needing to load or transform it. This combination meets the 90-day retention requirement and supports querying semi-structured data using standard SQL via Athena's built-in JSON SerDe.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Amazon RDS for MySQL.
Why it's wrong here
RDS for MySQL requires a fixed relational schema, so semi-structured JSON logs cannot be stored or queried natively without shredding them, and it is not built for large immutable log volumes. It is tempting because it offers familiar SQL, and would be correct for structured transactional data with defined columns.
- ✗
Amazon DynamoDB.
Why it's wrong here
DynamoDB is a key-value store queried through its own API, not SQL, and its item model does not suit ad-hoc analytical queries over JSON logs. It is tempting because it stores semi-structured items durably at scale, and would be correct for low-latency transactional lookups keyed by partition and sort key.
- ✓
Amazon S3 with Amazon Athena.
Why this is correct
Amazon S3 stores immutable JSON objects durably at low cost, while Athena queries them in place using standard SQL through the Glue Data Catalog. This satisfies the semi-structured, SQL-queryable, 90-day retention constraints without loading data into a separate database.
- ✗
Amazon ElastiCache for Redis.
Why it's wrong here
ElastiCache for Redis is an in-memory cache, not a durable queryable store, so it cannot retain immutable logs for 90 days or serve SQL. It is tempting because it handles high-throughput ingestion, and would be correct for caching hot query results or session data in front of a database.
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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Same concept, more angles
1 more way this is tested on DEA-C01
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. A data engineer needs to store semi-structured JSON logs from multiple microservices in a cost-effective manner for ad-hoc querying using SQL. Which AWS service should be used?
medium- ✓ A.Amazon Athena with data in S3
- B.Amazon DynamoDB
- C.Amazon RDS for MySQL
- D.Amazon Kinesis Data Analytics
Why A: Amazon Athena is the correct choice because it allows you to query semi-structured JSON logs stored in S3 directly using standard SQL, without needing to load or transform the data. Athena's schema-on-read approach and pay-per-query pricing make it highly cost-effective for ad-hoc analysis of large volumes of log data, as you only pay for the data scanned during queries.
JA
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.