Failover Subscription Revisited

When using a single partitioned topic, we saw that the first instance of a consumer connected to the topic and the second instance was able to connect but remained in standby. Let’s now take a look at how the Failover Subscription works for a topic with multiple partitions.

When using a Failover Subscription with a topic with multiple partitions, the behavior depends on the number of consumers compared to the number of partitions.

1. One consumer: The consumer will receive message from all partitions.
2. Fewer consumers than partitions: Each consumer may receive data from multiple partitions, but data from a single partition will all be routed to the same consumer.
3. Equal number of consumers and partitions: Each consumer will receive data from exactly one partition.
4. More consumers than partitions: If there are x number of partitions, x number of consumers will receive data from exactly one partition. Additional consumers will remain idle.

In all cases, message ordering is guaranteed on a per partition basis.