Amazon Web Services Updated SAA-C03 Exam Questions and Answers by trent

Why Option B is Correct:

Amazon SQS: Ensures no requests are lost, even during traffic spikes.

API Gateway: Handles dynamic traffic patterns efficiently, integrating with SQS for asynchronous processing.

Lambda: Polls the queue and processes requests in a serverless and scalable manner.

Dead-Letter Queue (DLQ): Ensures failed messages are retried or logged for debugging.

Why Other Options Are Not Ideal:

Option A: Elastic Beanstalk cannot handle queue-based decoupling, making it unsuitable for spiky traffic.

Option C: ALB to Lambda does not provide buffering for traffic spikes, risking request loss.

Option D: SNS is better suited for notifications, not reliable for ensuring message durability.

AWS References:

Amazon SQS:AWS Documentation - SQS

The key issue is repeated reads of identical data from an RDS MySQL database, which leads to unnecessary database load and degraded performance. The AWS-recommended solution for this pattern is to introduce an in-memory cache between the application and the database.

Amazon ElastiCache (Redis OSS) is purpose-built for caching frequently accessed data with microsecond-level latency. By caching identical query results, the backend EC2 instances can serve responses directly from memory instead of repeatedly querying the database. This significantly reduces read pressure on the RDS instance and improves overall application performance and scalability.

Option B is correct because Redis integrates cleanly with EC2-based applications and supports advanced caching patterns such as key expiration, eviction policies, and fine-grained control over cached objects. This approach also improves resilience during traffic spikes by offloading work from the database.

Option A is incorrect because SNS is a messaging service and does not cache or accelerate database queries. Option C is incorrect because DynamoDB Accelerator (DAX) works only with DynamoDB tables, not Amazon RDS. Option D is designed for streaming data ingestion and analytics, not for optimizing synchronous database access.

Therefore, B is the correct solution because it addresses the root cause of the performance problem by caching repeated database reads, following AWS best practices for high-performing application architectures.

AWS RDS Proxy is a fully managed, highly available database proxy that allows applications to pool and share database connections efficiently.

In serverless architectures like Lambda, rapid invocations can open numerous concurrent connections to Aurora, potentially overwhelming the database and causing “too many connections” errors.

By using Amazon RDS Proxy, the solution:

Pools database connections.

Maintains warm connections that can be reused.

Supports IAM authentication and Secrets Manager integration.

Requires minimal application change and low operational effort.

This directly supports the Performance Efficiency pillar of the AWS Well-Architected Framework, ensuring the application scales without overloading the DB.

???? Reference:

Amazon RDS Proxy Documentation

Lambda + RDS Best Practices