Redis Pub/Sub persistence

Question

I am working on redis SMQ persistence. My questions here is, While publisher publishing the messages, consumer has stopped suddenly. When consumer connects again, is it possible to subscribe messages from where it has stopped?

Answer 1

No - Redis' Pub/Sub has no persistence, and once a message has been published, it is sent only to the connected subscribed clients. Afterwards, the message is gone forever.

Answer 2

With standard Pub/Sub you can use Lua scripts to persist your message. You need to check whether you have a listener on channel or not. If not then storing your message with channel key on redis . When the subscriber cames back it checks if there is anything for him based on channel key. Second option is to use Redis Stream. Check this gist.