DBS-C01 Workload-Specific Database Design Practice Question
A company is designing a database for a social media application that stores user posts. Each post can have multiple tags. The workload requires low-latency queries to find all posts with a specific tag. Which database design is most suitable?
⚠ Common exam trap
Many candidates choose Amazon RDS for MySQL (Option C) due to familiarity with normalized relational designs, overlooking that DynamoDB's GSI provides superior performance and scalability for high-velocity, low-latency tag-based queries without the overhead of JOINs.
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 DynamoDB with a Global Secondary Index on the tag attribute.
Amazon DynamoDB with a Global Secondary Index (GSI) on the tag attribute is the most suitable design because it allows low-latency queries to find all posts with a specific tag without scanning the entire table. The GSI enables efficient querying by tag as a partition key, supporting the required access pattern with consistent single-digit millisecond performance at any scale.
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 ElastiCache for Memcached storing posts and tags as key-value pairs.
Why it's wrong here
ElastiCache is not a persistent data store.
- ✓
Amazon DynamoDB with a Global Secondary Index on the tag attribute.
Why this is correct
GSI provides fast query by tag.
- ✗
Amazon RDS for MySQL with a normalized schema and JOIN queries.
Why it's wrong here
JOINs add latency.
- ✗
Amazon Neptune with a graph model for tags and posts.
Why it's wrong here
Overkill for simple tag lookup.
Go deeper
Related to this question
About these practice questions
This DBS-C01 question is part of Courseiva's 1,663-question bank — original exam-style content with full explanations and wrong-answer analysis, never real exam questions or exam dumps. Learn why practice questions differ from exam dumps →
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This DBS-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 DBS-C01 exam.