SAA-C03 Design High-Performing Architectures Practice Question
A retail company runs a stateless web tier on Amazon EC2 instances behind an Application Load Balancer. During flash sales, response times spike because each request triggers many database queries. The team wants to reduce database load and improve read latency for product catalog pages that change only a few times per day. Which solution is MOST appropriate?
⚠ Common exam trap
The trap here is scaling the web tier when the real bottleneck is repeated reads on the database, which caching solves far more directly.
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
✓
Deploy an Amazon ElastiCache for Redis cluster and cache the catalog query results.
Caching the catalog query results in ElastiCache for Redis removes most repeated database reads and serves product pages from memory, which directly cuts database load and read latency. DynamoDB migration is invasive, Performance Insights only diagnoses, and adding web instances increases pressure on the database rather than relieving it.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Add more EC2 instances to the web tier behind the load balancer.
Why it's wrong here
Scaling out the web tier increases the number of clients hitting the database, which can worsen database contention during flash sales. The bottleneck described is database query volume and read latency, not web-tier compute. More web instances do not reduce the number of catalog queries executed.
- ✗
Enable Amazon RDS Performance Insights and tune the slowest queries.
Why it's wrong here
Performance Insights is a diagnostic tool that surfaces where time is spent; it does not itself reduce load. Query tuning may help, but with flash-sale bursts the same queries still execute on every request. This option improves observability rather than adding a scaling layer for read traffic.
- ✓
Deploy an Amazon ElastiCache for Redis cluster and cache the catalog query results.
Why this is correct
ElastiCache for Redis provides an in-memory cache that absorbs repeated catalog reads, cutting database load and returning results in sub-millisecond time. Because catalog data changes only a few times per day, a time-to-live cache with invalidation on update keeps data fresh while dramatically reducing query volume during flash sales.
- ✗
Move the catalog tables to Amazon DynamoDB with on-demand capacity.
Why it's wrong here
DynamoDB can scale reads well, but migrating relational catalog tables is a large change, and on-demand capacity still charges per read request. The application's access patterns and joins may not map cleanly to a key-value model. This adds migration risk without the sub-millisecond caching benefit of an in-memory tier.
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Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official Amazon Web Services exam blueprint
This SAA-C03 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 SAA-C03 exam.