What is the socket.io-redis-adapter for?

Question

Redis

Hi all. I have a simple question. I don't quite understand what Socket.io-redis-adapter is for? What role does the Redis database play?

Answer 1

When there is a heavy load, you need to split the websocket servers. After separation, it is more difficult to make broadcast distribution. And in order for one server to do it, you need to somehow get information about all the clients that are connected to all servers and send them a message. This is the information stored in redis. This is very simplified and short.