The Simple Queue Service is a service that delivers a highly available message queue service and operates on a standard HTTP access model. It has the potential to deliver unlimited message capacity for any application size and is delivered as a pay-per-request service, so your costs of running the queue service automatically scale with the size of your application.
A queue is essentially used as a message repository that stores the message on a distributed cluster of servers. Once the message is stored, it can be made visible for consumers to read or made invisible, which means stored but not ready to be read. When messages are produced, they are stored on the cluster with a randomized distribution, as shown in this diagram:
Here, we see the messages A, B, C, D, and E which were produced in that sequence being randomly distributed across a set of hosts in the...