Quick Answer
The answer is Amazon RDS for PostgreSQL. This is the correct choice because the social media application requires a relational database that natively supports complex JOIN queries across user profiles, posts, comments, and likes, and RDS provides a fully managed PostgreSQL engine optimized for such relational workloads. On the AWS Certified Database Specialty DBS-C01 exam, this question tests your ability to distinguish between relational and non-relational services under variable traffic; a common trap is choosing DynamoDB for its scalability, but it lacks JOIN support, while ElastiCache is only a cache and Neptune is a graph database overkill for standard relational joins. Remember that when you need to run complex JOINs on structured data with read replicas for traffic spikes, think RDS for PostgreSQL. Memory tip: "PostgreSQL Joins Social Feeds" — PostgreSQL handles the joins, RDS handles the scaling.
This DBS-C01 practice question tests your understanding of workload-specific database design. Match the stated requirement to the specific cloud service, access model, or configuration option — many options are valid in isolation but not for this scenario. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A startup is building a social media application that requires storing user profiles, posts, comments, and likes. The workload has variable traffic, with spikes after marketing campaigns. The team expects to run complex JOIN queries to generate a user's feed. Which AWS database service is MOST suitable for this relational workload?
Amazon Neptune
Why wrong: Neptune is a graph database, not suited for typical relational queries.
Amazon RDS for PostgreSQL
RDS PostgreSQL offers full relational capabilities and managed scaling.
Amazon DynamoDB with global secondary indexes
Why wrong: DynamoDB cannot perform JOINs; application-level joins would be complex and slow.
Amazon ElastiCache for Redis
Why wrong: ElastiCache is a cache, not a durable database for primary data.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
Amazon RDS for PostgreSQL
Amazon RDS provides managed relational databases (MySQL, PostgreSQL) that support complex JOINs and can be scaled vertically or with read replicas. Option B is wrong because DynamoDB is NoSQL and does not natively support JOINs. Option C is wrong because ElastiCache is an in-memory cache, not a primary database. Option D is wrong because Neptune is a graph database, which is overkill and not optimized for typical relational queries.
Key principle: NAT direction and interface roles matter as much as the IP address mapping. Inside/outside designation controls which traffic is translated.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
Amazon Neptune
Why it's wrong here
Neptune is a graph database, not suited for typical relational queries.
Amazon RDS for PostgreSQL
Why this is correct
RDS PostgreSQL offers full relational capabilities and managed scaling.
Related concept
Static NAT maps one inside address to one outside address.
Amazon DynamoDB with global secondary indexes
Why it's wrong here
DynamoDB cannot perform JOINs; application-level joins would be complex and slow.
Amazon ElastiCache for Redis
Why it's wrong here
ElastiCache is a cache, not a durable database for primary data.
Common exam traps
NAT is not only about the public address. The inside/outside interface roles and the ACL or rule that matches traffic are just as important.
Detailed technical explanation
NAT questions usually test address translation, overload/PAT behaviour, static mappings and whether the right traffic is being translated. Read the interface direction and address terms carefully.
Key takeaway
NAT direction and interface roles matter as much as the IP address mapping. Inside/outside designation controls which traffic is translated.
Real-world example
An e-commerce site experiences heavy traffic on Black Friday and near-zero traffic during off-peak weeks. Rather than provisioning permanent large VMs, the team uses auto-scaling groups that add capacity automatically under load and reduce it overnight. Questions like this test whether you understand elasticity, availability zones, and cloud compute scaling patterns.
What to study next
Review the four NAT address types (inside local, inside global, outside local, outside global), PAT port overload, and static vs dynamic NAT use cases. Then practise related DBS-C01 NAT questions on configuration and troubleshooting.
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FAQ
Workload-Specific Database Design — This question tests Workload-Specific Database Design — Static NAT maps one inside address to one outside address..
The correct answer is: Amazon RDS for PostgreSQL — Amazon RDS provides managed relational databases (MySQL, PostgreSQL) that support complex JOINs and can be scaled vertically or with read replicas. Option B is wrong because DynamoDB is NoSQL and does not natively support JOINs. Option C is wrong because ElastiCache is an in-memory cache, not a primary database. Option D is wrong because Neptune is a graph database, which is overkill and not optimized for typical relational queries.
Review the four NAT address types (inside local, inside global, outside local, outside global), PAT port overload, and static vs dynamic NAT use cases. Then practise related DBS-C01 NAT questions on configuration and troubleshooting.
Static NAT maps one inside address to one outside address.
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Last reviewed: Jun 20, 2026
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.
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