AWS Simple Queue Service Introduction

• It is the Oldest AWS Offering (over 15 years as of 2024)
• Used to decouple applications.
• Scales from 1 message/second to 10,000 messages/second
• Default Retention of message: 4 days (but it can go upto 14 days)
• No Limit how many messages can be in the Queue.
• Messages are deleted after they are read by comsumers
• Low Latency (< 10ms on publish/recieve)
• consumer share the work to read message & scale horizontally

SQS to decouple between application tiers

Lets say we have a website hosted on webservers, and it provides a video processing service. The 2nd set og ASG EC2, will be reading from the SQS queue and processing data. The webservers act as producers and put data into SQS Queue while Video Processing Servers act as consumers. The Awesome thing about it is that we can scale the second ASG independently from the first (& thats why its called coupling)

SQS Queue - Fifo Queue

As its name suggests, FIFO preserves the order of items coming in the queue, unlike normal queue. Thats all!