Hello, I’ve recently developed a module that creates distributed user counters, based on what’s described in this post Basically, locally I use ETS table to atomically know how many people there is in a channel, then I aggregate all counters of all nodes using Phoenix Tracker. In summary, users s…

If you were using a sorted set you wouldn’t be making this post because it solves the exact issue your post is about with regards to counting and distributing users to rooms atomically. So you saying that if I use redis I could get the current count for a channel across all nodes, while hundreds …

[image] Phxie: I should also add, one of the reasons I’m pushing Redis so hard is that I was desgning something with ETS/Genservers a year or so ago for a couple of week before I hit a wall and finally tried Redis. Redis made everything 10x easier for me. The big change here is not GenServer …

Yes that’s what I think, and I don’t see how I could have a performant algorithm if I have to get the updated global counter value from redis ? I think what you said early makes sense. I need to make some compromise regarding that max value, and probably accept that at certain moments, the counter…

[image] jaybe78: So you saying that if I use redis I could get the current count for a channel across all nodes, while hundreds of thousands of users are joining ? Yes. Redis can give you an atomic, cross‑node count while users join and leave in real time. It won’t match ETS’s raw speed, but…

Don’t take it personal dude. :smiley: I haven’t said what you say is wrong. I’m just asking questions. :slight_smile: Concerning Redis I thought about using it. I use AWS, so I could use it but it’s really expensive. I could deploy my own redis, but at this point I don’t feel like managing my o…

[image] LostKobrakai: The big change here is not GenServer vs. Redis though. It’s centralized storage of data (CP) vs. distributed storage of data (eventual consistency / AP) I never said Redis vs Genservers though. I said ETS/Genservers, meaning the combination of ETS as a tracker/counter an…

I’m a little confused with what’s going on in this thread. There’s an implication here that Redis is somehow different than using ETS tables, but there is no reason you can’t just put an ETS table on one node and use it exactly like you would use Redis! You would have no fault tolerance and higher l…

To the OP, I think you need to take a step back here. What are the rooms for? What do they contain? Messages? State? Where is that information stored? Do you need fault tolerance, or are the rooms ephemeral? Assuming it’s not a big deal to “lose” a room, it’s okay to store each room’s state in on…

I’m confused as to why you’re confused because I’ve explained my thoughts on the differences between ETS and Redis multiple times. More importantly, this was not meant to be the ETS vs Redis debate it became. OP posted an issue and said: [image] jaybe78: At this point, I\m running out of idea…

I’m actually here to hear different opinions… no one is holding the absolute truth on anything… Stop taking things personally. He has the right to disagree with you. Sorry you feel that way.

Implementing distributed user counters

Questions & Help Questions

karlosmid June 14, 2025, 10:22am 18

Hi, maybe distributed cachex is an option to check: