Quick Answer
The answer is Amazon ElastiCache for Redis, which is the best-suited AWS database service for a real-time news feed database ElastiCache Redis workload because it natively combines sorted sets and pub/sub capabilities. Sorted sets allow you to maintain a time-ordered feed per user, efficiently fetching the latest posts, while pub/sub enables instant broadcasting of new content to all active subscribers, ensuring sub-millisecond updates. On the AWS Certified Database Specialty DBS-C01 exam, this question tests your ability to differentiate between in-memory caching for real-time aggregation versus transactional or key-value stores; a common trap is choosing DynamoDB for its speed, but DynamoDB lacks native sorted set ordering and pub/sub for cross-user feed assembly. Remember the memory tip: “Redis sorts and shouts”—sorted sets organize the feed, and pub/sub shouts updates to all followers.
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 with a news feed feature. The feed must be personalized and updated in real-time as users post. Which AWS database service is best suited for this workload?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "best"
Why it matters: Signals that multiple options may be partially correct. Choose the option that most directly solves the exact problem described, not the one that sounds most complete.
Amazon DynamoDB with Global Secondary Indexes
Why wrong: DynamoDB is not optimized for real-time feed aggregation.
Amazon S3 with Select and Glacier
Why wrong: S3 is object storage, not a real-time database.
Amazon RDS for PostgreSQL with read replicas
Why wrong: RDS is not designed for real-time sub-millisecond updates.
Amazon ElastiCache for Redis with sorted sets and pub/sub
Redis provides real-time data structures and pub/sub for feeds.
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 ElastiCache for Redis with sorted sets and pub/sub
Option C is correct because Amazon ElastiCache for Redis supports sorted sets and pub/sub, ideal for real-time feeds. Option A is wrong because DynamoDB is optimized for key-value access, not for real-time feed aggregation across many users. Option B is wrong because RDS is not designed for sub-millisecond real-time updates. Option D is wrong because S3 is object storage, not a database for real-time queries.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
Amazon DynamoDB with Global Secondary Indexes
Why it's wrong here
DynamoDB is not optimized for real-time feed aggregation.
Amazon S3 with Select and Glacier
Why it's wrong here
S3 is object storage, not a real-time database.
Amazon RDS for PostgreSQL with read replicas
Why it's wrong here
RDS is not designed for real-time sub-millisecond updates.
Amazon ElastiCache for Redis with sorted sets and pub/sub
Why this is correct
Redis provides real-time data structures and pub/sub for feeds.
Clue confirmation
The clue word "best" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
Many certification questions include familiar terms but test a specific constraint. Read the exact wording before choosing an answer that is generally true but wrong for this case.
Detailed technical explanation
This question should be treated as a scenario, not a definition check. Identify the problem, the constraint and the best action. Then compare each option against those facts.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
A media company stores terabytes of video archives that are accessed once a year for audit purposes. Moving these objects to a cold storage tier (Azure Archive, S3 Glacier, or Google Nearline) costs a fraction of hot storage. Questions like this test whether you understand storage tiers, access frequency tradeoffs, and retrieval latency requirements.
What to study next
Identify which DBS-C01 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
Workload-Specific Database Design — study guide chapter
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FAQ
Workload-Specific Database Design — This question tests Workload-Specific Database Design — Read the scenario before looking for a memorised answer..
The correct answer is: Amazon ElastiCache for Redis with sorted sets and pub/sub — Option C is correct because Amazon ElastiCache for Redis supports sorted sets and pub/sub, ideal for real-time feeds. Option A is wrong because DynamoDB is optimized for key-value access, not for real-time feed aggregation across many users. Option B is wrong because RDS is not designed for sub-millisecond real-time updates. Option D is wrong because S3 is object storage, not a database for real-time queries.
Identify which DBS-C01 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
Yes — watch for: "best". Signals that multiple options may be partially correct. Choose the option that most directly solves the exact problem described, not the one that sounds most complete.
Read the scenario before looking for a memorised answer.
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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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