Question #1749
A logistics tracking platform uses Amazon EC2 instances and an Amazon Aurora PostgreSQL DB cluster. As user activity grows, EC2 instance usage remains stable, but the DB cluster's workload increases significantly. The company added a read replica, which temporarily reduced the load, but the workload continues to rise. Analysis reveals that the increased load stems from frequent repeated read queries on user activity logs. The company needs a cost-effective solution to reduce the read load on the DB cluster.
Which solution will meet these requirements MOST cost-effectively?
Implement an Amazon ElastiCache for Redis cluster between the application and the DB cluster.
Add an additional read replica to the DB cluster.
Configure Aurora Auto Scaling for the Aurora read replicas.
Modify the DB cluster to use a Multi-Master configuration.
Explanation
The correct answer is A because:
- ElastiCache for Redis caches repeated read queries in memory, reducing direct database hits. This directly addresses the root cause (frequent repeated queries) and lowers the read load on Aurora, making it cost-effective.
- Option B (additional read replica) adds infrastructure costs and does not reduce the total number of queries, only distributes them.
- Option C (Aurora Auto Scaling) dynamically adds replicas but incurs ongoing costs and does not optimize query patterns.
- Option D (Multi-Master) focuses on write scalability and high availability, not read-heavy workloads.
Key Points:
- Caching is ideal for repeated read queries.
- ElastiCache reduces database load more efficiently than scaling replicas.
- Cost-effectiveness prioritizes reducing query volume over scaling infrastructure.
Answer
The correct answer is: A