AWS Certified Solutions Architect - Associate

Explanation

Correct Answer: A

Why Option A is correct:

1. FIFO (First-In-First-Out) queue maintains the exact order of messages, which is critical for this requirement where "data is written in a specific order that must be maintained throughout processing."
2. AWS Lambda integration with SQS provides a serverless, event-driven processing model that minimizes operational overhead.
3. SQS FIFO queues guarantee exactly-once processing and preserve the order of messages, making them ideal for ordered data processing scenarios.
4. Minimal operational overhead is achieved through the serverless nature of Lambda and managed service nature of SQS.

Why other options are incorrect:

Option B (SNS + Lambda):

• SNS topics do not guarantee message ordering. Messages can be delivered to subscribers in any order.
• While Lambda can process messages, the lack of ordering guarantee makes this unsuitable for the requirement.

Option C (SQS Standard Queue + Lambda):

• Standard SQS queues provide best-effort ordering but do NOT guarantee FIFO ordering.
• Messages might be delivered out of order, violating the requirement for maintaining specific order.

Option D (SNS + SQS):

• While this adds durability through SQS, SNS still doesn't guarantee ordering of messages.
• The SQS queue would receive messages in potentially random order from SNS.
• This adds unnecessary complexity without solving the ordering requirement.

Key AWS Concepts:

• SQS FIFO queues are specifically designed for scenarios requiring strict message ordering and exactly-once processing.
• AWS Lambda with SQS event source mapping automatically scales to process messages and handles retries on failures.
• This combination provides a fully managed, serverless solution with minimal operational overhead while meeting the ordering requirement.