These questions are independently created for study purposes. They are not official AWS exam questions, actual exam questions, leaked questions, or exam dumps.
SAA-021
You need to process millions of small messages asynchronously. Strict ordering is not required, and you want the highest possible throughput. Which queue is the most appropriate?
Choices
Explanation and answer
Read the explanation and correct answer (spoiler — try answering first)
Correct answer: A. Amazon SQS Standard Queue
Explanation
SQS Standard Queue is well suited to high-throughput message processing. It is a good fit when strict ordering is not required.
Per-choice explanations
A. Amazon SQS Standard Queue
Correct. It is well suited to high-throughput asynchronous processing.
B. Amazon EFS
Incorrect. EFS is a shared file storage service.
C. AWS Config
Incorrect. AWS Config records and evaluates resource configurations.
D. Amazon SQS FIFO Queue
Incorrect. FIFO Queue is used when ordering is required, but it has tighter limits than Standard Queue.
Practical Use
Amazon SQS offers two queue types: Standard Queue and FIFO Queue. Standard Queue provides nearly unlimited throughput (effectively unlimited TPS within regional limits), best-effort ordering, and at-least-once delivery. The lack of strict ordering allows messages to be distributed across multiple internal nodes, which delivers very high throughput. This makes it well suited as an asynchronous buffer for processing millions of small messages. FIFO Queue provides strict ordering and deduplication (exactly-once processing) in exchange for a default limit of 300 messages per second per message group (3,000 messages per second with batching). High Throughput for FIFO can extend this to several thousand TPS, but throughput will not scale unless message group IDs are designed appropriately. Unless ordering is a business requirement, Standard Queue is the default choice because it is favorable in both cost and scalability. On SAA-C03, keywords such as "high throughput," "strict ordering not required," and "millions of messages" point to Standard Queue. Conversely, requirements such as "deduplication," "strict ordering," or "deterministic processing for financial or inventory updates" point to FIFO Queue. The distinction with SNS and EventBridge is also a frequent topic: SNS for pub/sub fan-out, EventBridge for event-driven routing, and SQS for message buffering and retries.