Nice @JamilAhmed , I like this idea! Use the replay queue for any number of consumers that come and go. They create a tempQ when they connect, and just request everything from the last RGMID they’d seen.
Next question: who/where/what stores that RGMID? Dumb applications might not want to have to manage that themselves. Now we’re into the “Zookeeper keeping track of offsets” issue that Kafka has/had. An LVQ per consumer is too heavy. PS+Cache could be used, but is not Guaranteed.