How expensive are topics?

[gmencz]

Are topics expensive or not? Could I use millions of topics (topic per user for example) without trouble?

[ghost]

Topics are expensive and not suited for per-user

[gmencz]

Okay, I always overthink these kinds of things because "What if I have a million elements in the set and I need to iterate over them, that will be really slow".

[ghost]

;D

[gmencz]

So, one last question regarding topics being "expensive", would topics be suitable for something like Discord? Where each server is a topic users subscribe to? I'm assuming you're familiar with Discord but if not I'd be more than happy to explain how it would work by using pubsub.

If using the built in pubsub isn't suitable then I guess I'd keep the channels separate in some Map along with the sockets but then if I have to broadcast to all sockets I'd have to use a for-loop and run into some perf issues when the sockets grow.

[ghost]

Yes Discord Server is a much better granularity. 1 per connection is too fine, 1 per Discord Server is fine. but try and load balance connections so that one instance holds only a limited set of topics anyways.

[gmencz]

Alright, are there any benchmarks regarding topics? I'm going to benchmark them myself on my machine but it would be nice to have some "general" benchmarks data.