AWS Database, Messaging and Application Services Quick Notes (Numbers)

Elasticache for redis support both single-node and up to 15-shard clusters are available, enabling scalability to up to 3.55 TiB of in-memory data.

For standard SQS queues, there can be a maximum of 120K inflight messages per queue. For FIFO SQS queues, max is 20K.

The default message retention period in SQS is 4 days.

In SQS, you can set the message retention period to a value from 60 seconds to 1,209,600 seconds (14 days) using the SetQueueAttributes action. 

With long polling in SQS, consumer requests wait until a message is available or the long polling request times out. Maximum timeout is 20 seconds.

All customers can make 1 million Amazon SQS requests for free each month.

SQS messages can contain upto 256 KB of text in any format.

A single request can have from 1 to 10 messages, up to a maximum total payload of 256 KB.

Each SQS queue starts with a default setting of 30 seconds for the visibility timeout. Maximum timeout is 12 hours.

First 1 million Amazon SNS requests per month are free.

Amazon SNS currently allows a maximum limit of 256 KB for published messages.

In SNS, each 64KB chunk of published data is billed as 1 request.

The maximum life-span of an SWF task or workflow execution is 1 year.