SAP-C02 Design for New Solutions Practice Question
A company is migrating a monolithic application to microservices on Amazon ECS with Fargate. The application currently uses a central MySQL database. The architects plan to refactor the database into separate RDS instances per microservice. Which strategy will ensure data consistency across services with minimal application changes?
⚠ Common exam trap
Watch out — candidates often confuse eventual consistency with read replicas (Option C) or assume that traditional ACID transactions can be extended across separate databases (Option D), but the saga pattern is the correct distributed consistency approach for microservices with separate databases.
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
✓
Implement a saga pattern using choreography, where each service publishes events and reacts to events from other services.
The saga pattern with choreography allows each microservice to maintain its own RDS instance while ensuring data consistency through a sequence of local transactions and compensating events. This approach avoids the need for distributed transactions across separate databases, which aligns with the goal of minimal application changes by leveraging existing event-driven communication patterns in ECS with Fargate.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Enable the STRICT_TRANS_TABLES SQL mode on all RDS instances to enforce data integrity.
Why it's wrong here
STRICT_TRANS_TABLES is a MySQL mode for strict SQL handling, not a distributed consistency solution.
- ✓
Implement a saga pattern using choreography, where each service publishes events and reacts to events from other services.
Why this is correct
The saga pattern with choreography maintains data consistency across microservices without tight coupling, and can be implemented with minimal changes using event-driven communication.
- ✗
Configure RDS read replicas for each service to ensure eventually consistent reads.
Why it's wrong here
Read replicas provide eventual consistency but not for writes; they don't solve write consistency across services.
- ✗
Use distributed transactions with a two-phase commit protocol across RDS instances.
Why it's wrong here
Two-phase commit is not supported across separate RDS instances and would require a transaction manager, adding complexity.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This SAP-C02 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 SAP-C02 exam.