Akka Distributed Pub/Sub and number of named topics

Question

I would like to create a named topic per online user in my system using akka clustering. Does having couple of 10000s named topic at a time impact the performance negatively?

Answer 1

I would not recommend. Topic information is represented by a service key in the Receptionist. Between 10k and 100k is probably OK, above will most likely give you some performance issues.

Depending on what you need, using cluster sharding might be a better fit.