If you want to use ETS that’s fine, I was just pointing out that Redis is designed to handle what you’re trying to do in a way that ETS and Genservers are not. Your trying to add cross node functionality to tools that are for local use, rather than use a tool that will work cross node by default.
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.
Again, you mentioned this above as well. With a sorted set you would just go down the list until you find a vacant spot and then fill it. If no vacant spots exist you create a new room. Sorted sets are ordered by highest counts.
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.
