DEA-C01 Data Store Management Practice Question
A data engineer needs to store semi-structured JSON data that is accessed infrequently but requires millisecond retrieval latency. The data is immutable once written. Which AWS service is most cost-effective?
⚠ Common exam trap
Watch out — candidates often assume infrequent access requires a database like DynamoDB or RDS, but S3 Select with Standard-IA provides the same millisecond retrieval latency for small filtered queries at a fraction of the cost, especially for immutable data.
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 (Standard-IA) with S3 Select
Amazon S3 Standard-IA with S3 Select is the most cost-effective choice because it provides infrequent access storage at low cost while S3 Select enables server-side filtering to retrieve only the required subset of JSON data, achieving millisecond latency for small queries on immutable data without the overhead of a full database.
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 DynamoDB with on-demand capacity
Why it's wrong here
DynamoDB is optimized for frequent access and may be more expensive for infrequent use.
- ✗
Amazon ElastiCache for Redis
Why it's wrong here
ElastiCache is an in-memory cache, not a durable data store.
- ✗
Amazon RDS for PostgreSQL with JSONB
Why it's wrong here
RDS is relational and overkill for simple JSON storage with low access frequency.
- ✓
Amazon S3 (Standard-IA) with S3 Select
Why this is correct
S3 Select can retrieve subsets of JSON data efficiently, and Standard-IA is cost-effective for infrequent access.
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.