The answer is Amazon DynamoDB with DAX, because DynamoDB Accelerator is an in-memory cache that delivers microsecond read latency, making it the ideal choice for an e-commerce catalog with frequent reads and occasional writes. DAX sits between your application and DynamoDB, caching hot data to bypass the disk-based latency of the base table, which is critical for low latency reads for e-commerce database scenarios. On the AWS Certified Database Specialty DBS-C01 exam, this question tests your understanding of when to use caching services versus read replicas—a common trap is choosing RDS with read replicas, which improve throughput but cannot match DAX’s sub-millisecond performance. Remember that DAX is purpose-built for DynamoDB’s key-value and document model, not for relational data, but the question prioritizes speed over relational structure. Memory tip: DAX = Data Accelerator for eXceptional speed, or think “DAX dashes past RDS replicas for microsecond reads.”
DBS-C01 Workload-Specific Database Design Practice Question
This DBS-C01 practice question tests your understanding of workload-specific database design. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. 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 company is designing a database for an e-commerce platform that stores product catalog data. The catalog has frequent reads and occasional writes. The data is highly relational but the team wants the lowest possible latency for read queries. Which database service should they choose?
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 DAX
DynamoDB Accelerator (DAX) is an in-memory cache for DynamoDB that provides microsecond read latency. While DynamoDB itself is NoSQL, DAX is used to speed up reads. RDS with read replicas can improve read performance but not to microsecond level. ElastiCache could be used but requires more application logic. DocumentDB is a document database not optimized for microsecond reads.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
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 DocumentDB
Why it's wrong here
DocumentDB is a document database with millisecond latency, not microsecond.
✗
Amazon RDS for PostgreSQL with read replicas
Why it's wrong here
RDS read replicas reduce read load but add replication lag and do not provide microsecond latency.
✓
Amazon DynamoDB with DAX
Why this is correct
DAX provides in-memory acceleration for DynamoDB, delivering microsecond read latency.
Related concept
Read the scenario before looking for a memorised answer.
✗
Amazon ElastiCache for Redis
Why it's wrong here
ElastiCache is a caching layer, not a primary database, and would require additional application complexity.
Common exam traps
Common exam trap: answer the scenario, not the keyword
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
How to think about this question
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.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
Use explanations to understand the rule behind the answer.
TExam Day Tips
→Underline the problem statement mentally.
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A cloud solutions architect for a retail company is evaluating services for a new workload. The correct answer here reflects best practice for the specific scenario described — not a general cloud recommendation. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Cloud exam questions reward reading the constraint carefully: the same technology can be right or wrong depending on the use case.
What to study next
Got this wrong? Here's your next step.
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 — This question tests Workload-Specific Database Design — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Amazon DynamoDB with DAX — DynamoDB Accelerator (DAX) is an in-memory cache for DynamoDB that provides microsecond read latency. While DynamoDB itself is NoSQL, DAX is used to speed up reads. RDS with read replicas can improve read performance but not to microsecond level. ElastiCache could be used but requires more application logic. DocumentDB is a document database not optimized for microsecond reads.
What should I do if I get this DBS-C01 question wrong?
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.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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Question Discussion
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