Redis PubSub 订阅机制是如何工作的？

Question

我想创建一个发布-订阅基础架构，其中每个订阅者都将收听多个（比如 100k）频道。

我认为为此目的使用 Redis PubSub，但我不确定订阅数千个频道是否是这里的最佳做法。 为了回答这个问题，我想知道 Redis 中的订阅机制是如何在后台工作的。

另一种选择是为每个订阅者创建一个频道并在其间放置一些组件，这将获取所有消息并将其发布到相关频道。

还有其他想法吗？

Answer 1

Salvatore/Redis 的创建者在这里回答了这个问题：https://groups.google.com/forum/#!topic/redis-db/R09u__3Jzfk

All the complexity on the end is on the PUBLISH command, that performs
an amount of work that is proportional to:

a) The number of clients receiving the message.
b) The number of clients subscribed to a pattern, even if they'll not
match the message.

This means that if you have N clients subscribed to 100000 different
channels, everything will be super fast.

If you have instead 10000 clients subscribed to the same channel,
PUBLISH commands against this channel will be slow, and take maybe a
few milliseconds (not sure about the actual time taken). Since we have
to send the same message to everybody.