SNS and SQS integration pattern (fan-out) in AWS - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the main purpose of the SNS and SQS fan-out pattern?

It allows a single message published to an SNS topic to be delivered to multiple SQS queues, enabling parallel processing by different consumers.

beginner

How does SNS deliver messages to SQS queues in the fan-out pattern?

SNS pushes the message to all subscribed SQS queues immediately after a message is published to the SNS topic.

intermediate

Why use SQS queues with SNS instead of having multiple subscribers directly on SNS?

SQS queues provide message durability, decoupling, and allow consumers to process messages at their own pace, improving reliability and scalability.

intermediate

What happens if one SQS queue subscriber is slow or down in the fan-out pattern?

The other queues still receive and process messages independently; the slow or down queue will accumulate messages until it recovers.

advanced

What is a best practice when configuring SNS and SQS fan-out integration?

Ensure each SQS queue has proper permissions to allow SNS to send messages, and configure dead-letter queues for handling failed message processing.

What AWS service acts as the message publisher in the fan-out pattern?

A DynamoDB

B SQS

C SNS

D Lambda

SNS is the service that publishes messages to multiple subscribers, including SQS queues.

In the fan-out pattern, how many SQS queues can an SNS topic send messages to?

A None

B Exactly two

C Only one

D Multiple, unlimited

SNS can deliver messages to multiple subscribed SQS queues simultaneously.

What feature of SQS helps handle messages if a consumer fails to process them?

A Auto-scaling

B Dead-letter queue

C Encryption

D Caching

Dead-letter queues store messages that could not be processed successfully for later inspection or reprocessing.

Which of the following is NOT a benefit of using the SNS and SQS fan-out pattern?

A Guaranteed message order across all queues

B Parallel processing of messages

C Decoupling of message producers and consumers

D Improved fault tolerance

SNS and SQS fan-out does not guarantee message order across multiple queues.

What must you configure to allow SNS to send messages to an SQS queue?

A SQS queue policy to allow SNS publish

B SNS topic policy to allow SQS subscribe

C IAM user permissions only

D No configuration needed

The SQS queue must have a policy that permits the SNS topic to send messages to it.

Explain how the SNS and SQS fan-out pattern works and why it is useful.

Think about one message reaching many receivers independently.

Describe best practices when setting up SNS and SQS fan-out integration.

Focus on security, reliability, and monitoring.