[_pgmf]

Streams are kinda cool but they have a distinctly different feel than the other data-types in Redis. They've got this invisible statefulness. Last ids, consumer group state, etc. I've tried implementing a couple little things with streams, and it's not necessary to use the consumer group stuff or whatever of course. I wonder why streams weren't made using the modules API, though? They seem just weird/different enough to warrant exclusion from the core data types, in my thinking. Anyways, just reading the title referring to streams as "pure" made me go wtf? Because there's a lot of hidden state in there.

[antirez]

Pure means that when you don't use consumer groups, there is no hidden state at all, and they are just a boring data structure like everything else in Redis. Only if you use the messaging part they have state, but this is an accessory part like a shell on top of what is otherwise exactly a vanilla data structure.

[coleifer]

Can you read from a stream that doesn't exist yet?