Please explain what is Kinesis data delivery stream is. Is it the same with Amazon Kinesis Data Streams or is this a technology specific to Firehose?
Kinesis data delivery stream is the underlying entity of Kinesis Data Firehose. You use Kinesis Data Firehose by creating a Kinesis data delivery stream and then sending data to it.
To use Firehose, you create Kinesis Data Firehose delivery stream. This is an entity which processes data and delivers it outcome to your destination, e.g. S3 or Redshift.
However, you have to ingest some data to the Kinesis Data Firehose delivery stream to start with. The data can by ingested directly, by using PutRecord api of the Firehose service, or you can connect a Kinesis Data Stream to the Kinesis Data Firehose delivery stream.
