DBS-C01 Workload-Specific Database Design Practice Question
A social media application stores user posts in an Amazon RDS for PostgreSQL instance. The application experiences a sudden spike in read traffic during peak hours, causing database bottlenecks. The team needs to improve read scalability without changing the application code. Which solution is MOST cost-effective?
⚠ Common exam trap
Many candidates confuse Multi-AZ with read scalability, but Multi-AZ only provides failover redundancy and does not allow the standby to serve read traffic, whereas Read Replicas are specifically designed for read offloading.
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 Amazon RDS for PostgreSQL Read Replicas
Amazon RDS for PostgreSQL Read Replicas allow you to offload read traffic from the primary DB instance to one or more read-only replicas, improving read scalability without any application code changes. This is the most cost-effective solution as it leverages the existing PostgreSQL engine and requires only minimal additional compute and storage costs for the 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.
- ✗
Migrate to Amazon DynamoDB with DAX
Why it's wrong here
Requires data model changes and application rewrite.
- ✗
Enable Multi-AZ on the RDS instance
Why it's wrong here
Multi-AZ provides high availability, not read scaling.
- ✓
Use Amazon RDS for PostgreSQL Read Replicas
Why this is correct
Read Replicas offload read traffic; requires minor configuration but no application code changes.
- ✗
Use Amazon ElastiCache to cache query results
Why it's wrong here
Requires application code changes to cache and retrieve data.
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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.