DBS-C01 Workload-Specific Database Design Practice Question
A social media company stores user posts in a database. Each post has a unique ID, content, and timestamp. The application frequently queries posts by user ID and also needs to support a global feed sorted by timestamp. Which database design is most efficient?
⚠ Common exam trap
Many candidates assume a relational database with indexes is always the best for sorted queries, but DynamoDB's GSI and sort key design can handle both access patterns more efficiently at scale, and the exam tests understanding of when to use NoSQL over SQL for high-throughput workloads.
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 user_id as partition key and timestamp as sort key, plus a GSI on timestamp
It uses user_id as the partition key and timestamp as the sort key for efficient per-user queries, while the Global Secondary Index (GSI) on timestamp allows the global feed to be sorted by timestamp without a costly scan. This design leverages DynamoDB's key-value and query capabilities to support both access patterns with low latency and minimal read capacity consumption.
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 a single table and scan operation for the global feed
Why it's wrong here
Scan operations are inefficient and should be avoided for frequent queries.
- ✗
Amazon S3 with a metadata index in DynamoDB
Why it's wrong here
This adds complexity and latency; DynamoDB alone can handle the workload.
- ✓
Amazon DynamoDB with user_id as partition key and timestamp as sort key, plus a GSI on timestamp
Why this is correct
This design efficiently supports both query patterns.
- ✗
Amazon RDS for PostgreSQL with indexes on user_id and timestamp
Why it's wrong here
RDS can handle the workload but may not scale as easily as DynamoDB for high write throughput.
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.