SAP-C02 Design for New Solutions Practice Question
A company is designing a new application that will use Amazon RDS for PostgreSQL. They need to implement read replicas to offload read traffic. However, they are concerned about replication lag affecting read consistency. Which action would minimize replication lag?
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
✓
Use instance types with higher network performance
Using an instance type with higher network performance (option D) reduces replication lag because it provides more bandwidth for the replication process. Option A (increasing allocated storage) does not directly affect replication lag. Option B (using an encrypted connection) does not impact lag; encryption adds overhead but is necessary for security. Option C (enabling Multi-AZ) is for high availability, not for read replicas.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Increase the allocated storage on the primary instance
Why it's wrong here
Allocated storage governs capacity and IOPS provisioning, not the rate at which the primary streams write-ahead log records to replicas. It is tempting because storage performance affects database throughput, but replication lag stems from replica-side apply capacity, so scaling the replica instance or its storage addresses it.
- ✗
Use an encrypted connection between the primary and replica
Why it's wrong here
Encryption secures data in transit between primary and replica; it adds no throughput and cannot reduce the delay in applying write-ahead log records. It is tempting because transport security sounds relevant to replication, but lag arises from replica apply capacity, addressed by scaling the replica instance.
- ✗
Enable Multi-AZ on the primary instance
Why it's wrong here
Multi-AZ maintains a synchronous standby in a second Availability Zone for failover; it does not accelerate asynchronous replication to read replicas. It is tempting because it improves resilience and availability, but lag stems from replica-side apply capacity, so scaling the replica instance reduces it.
- ✓
Use instance types with higher network performance
Why this is correct
Replication lag on RDS read replicas is primarily bounded by the network throughput between primary and replica and by write volume. Larger instance types with higher network performance let the replica apply the primary's WAL stream faster, reducing lag and improving read consistency.
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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.