Standard v/s FIFO : SNS & SQS

#aws #architecture #sns #sqs

Amazon SNS and Amazon SQS both offer Standard and FIFO variants of topics and queues respectively which helps you build better micro-service focused, de-coupled applications.
Some of the basic understanding of SNS and SQS with the technology and concepts behind is explained in -

Getting started with SNS and SQS

Jones Zachariah Noel for AWS Community Builders ・ Nov 14 '21

#sns #sqs #aws #architecture

The previous blog post explains about when and how to choose SNS or SQS for your application need.

When to : SNS or SQS

Jones Zachariah Noel for AWS Community Builders ・ Nov 21 '21

#sns #sqs #aws #architecture

And this blog post, will give you a better understanding of Standard and FIFO variants of topics and queues.

What is Standard topic/queue?

Standard topics/queues are used often when the system can handle messages which can arrive more than once and without a proper order.

What is FIFO topic/queue?

FIFO topics/queues follows the concept of First-in,First-out which guarantees the order of messages is very necessary. This strictly maintains the order of the message and also doesn't deliver the same message multiple times.

Standard v/s FIFO : SNS

Amazon SNS offers topics of two variants - Standard topics and FIFO topics.

Feature	Standard topics	FIFO topics
Throughput	Nearly unlimited no. of messages per second.	300 messages per second or 10 MB per second (whichever is first).
Message order	Order of messages will not be same as published order.	Order is maintained by following first-in-first-out (FIFO).
Message delivery	At-least once, can duplicate again.	Only once.
Subscription types	Amazon SQS, Amazon Kinesis Data Firehose, AWS Lambda Fns, HTTPS, SMS, Email, mobile push.	Only SQS FIFO queues.
Limits	100,000 standard topics with 12.5M subscriptions per topic per account.	1,000 FIFO topics with 100 subscriptions per topic per account.
Encryption (via AWS KMS)	Both at rest and in transit.	Both at rest and in transit.
Pricing (more info in SNS pricing)	First 1M requests free, $0.5 per 1M requests.	Publish and publish batch API requests are $0.30 per 1M and $0.017 per GB of payload data and subscription messages are $0.01 per 1M and $0.001 per GB of payload data.
Use-case	Whenever there is multi-subscriber scenario, Whenever the application can handle duplicate and unordered messages.	Whenever the need for ordering is a must.

Standard v/s FIFO : SQS

Amazon SQS offers queues of two variants - Standard queues and FIFO queues.

Feature	Standard queues	FIFO queues
Throughput	Nearly unlimited number of transactions per second per API action	300 message per second with a batch of 10 messages per operation.
Message order	Occasionally order of messages will not be same.	Order is maintained by following first-in-first-out (FIFO).
Message delivery	At-least once but can get a copy of the same message	Only once.
Message persistence	Max upto 14 days.	Max upto 14 days.
Encryption (via AWS KMS)	Both at rest and in transit.	Both at rest and in transit.
Resolvers / Triggers	Lambda Fns and SNS topics.	Lambda Fns and SNS topics.
Pricing (more info in SNS pricing)	First 1M requests free, $0.4 for 1M-100B requests, $0.24 for over 200B requests.	First 1M requests free, $0.5 for 1M-100B requests, $0.35 for over 200B requests.
Use-case	Whenever the application can handle unordered and multiple delivery of messages such as decoupling transaction ordering process, batch processes.	Whenever the message have to be ordered such as image/video decoding/encoding, using as subscriber to a FIFO topic.

Conclusion

Whenever choosing SNS or SQS choosing between Standard variant and FIFO variant is also necessary as the features of message ordering, exactly once delivery would help building efficient systems.