https://www.udemy.com/aws-certified-solutions-architect-associate/learn/v4/t/lecture/2050804?start=0

Simple Queue Service (SQS)

Amazon AWS is a web service that gives you access to a message queue that can be used to store messages while waiting for a computer to process them.

• Pull based, not push based
• 256 KB max message size
• Kept in the queue for 1 min up to 14 days
  • Default = 4 days
• Visibility Timeout starts after a reader picks up the message.
  • When the message is completed, it is deleted from the queue
  • If not completed before the timeout, the message becomes visible again and another reader will process it.
    • This could result in the same message being processed twice.
  • Visibility Time Out maximum=12 hours
• SQS guarantees your messages will be processed at least once
• Long Polling is a way to retrieve messages from your SQS queues.
  • Short polling returns immediately, even if the message queue is empty.
  • Long polling only returns a result
    • When a message is available in the queue
    • After the Long Poll times out.
• Queues can be standard or FIFO

Simple Workflow Service (SWF)

SWF Actors

• Workflow Starters – An application that can initiate a workflow.  Could be your e-commerce wiebsite when placing an order or a mobile app searching for bus times.
• Deciders – Control the flow of activity tasks in a workflow execution. If something has finished or fails in a workflow, a Decider decides what to do next.
• Activity Workers – Carry out the activity tasks.

Simple Notification Service (SNS)

• Subscribers
  • HTTP
  • HTTPS
  • Email
  • Email-JSON
  • SQS
  • Application
  • Lambda
• Push based, not poll based like SQS
• Subscribers must ‘subscribe’ to prevent spamming

Elastic Transcoder

• Converts media files from their original source format to different formats that will play on smart phones, tablets, PCs, etc.
• Provides transcoding presets for popular output formats, which means that you don’t need to guess about which settings work best on particular devices.
• Pay based on the minutes that you transcode and the resolution at which you transcode.

Kinesis

Kinesis Streams

• Data is stored in Shards
  • 1MB/s in, 2MB/s out
• Scaling depends on the number of Shards
• Output can go basically anywhere

Kinesis Firehose

• Data collected is sent immediately to:
  • S3
  • Lambda

Kinesis Analytics

• Sits on top of Streams or Firehose
• Allows queries to be ran then sent to
  • S3
  • Redshift
  • Elasticsearch Cluster

Kinesis Exam Tips

• Know the difference between Streams and Firehose
  • Streams use Shards
• Understand Analytics sits on top of Streams and Firehose.