Amazon SQS (Simple Queue Service)
Amazon Simple Queue Service (SQS) is a fully managed message queuing service that enables you to decouple and scale microservices, distributed systems, and serverless applications.
Key Features
- Decoupling: Separates producer and consumer components.
- Pull-based: Consumers poll the queue for messages.
- Standard Queues: Unlimited throughput, at-least-once delivery, best-effort ordering.
- FIFO Queues: Strictly preserves order (First-In-First-Out) and exactly-once processing.
- Visibility Timeout: Prevents other consumers from processing a message while it's being handled.
- Dead Letter Queues (DLQ): Handles messages that fail processing multiple times.
Exam Tips
- "Decouple components": Answer is SQS.
- "Buffering": SQS acts as a buffer between producers and consumers.
- "Poll / Polling": SQS is pull-based (polling).
- "Order is critical": Use FIFO Queues.
Common Use Cases
- Asynchronous Processing: Offloading tasks to background workers.
- Batch Processing: Buffering requests for batch jobs.
- Traffic Spikes: smoothing out high loads.