Integration / Apache Pulsar Interview questions
What are the subscription types in Pulsar?
Pulsar offers four subscription types: Exclusive (one consumer, full topic ordering), Failover (multiple registered consumers but only one active, providing hot-standby failover), Shared (many consumers round-robin messages with no ordering guarantee), and Key_Shared (many consumers, but same-key messages always go to the same consumer, preserving per-key order).
Choosing between them is really a choice about how strictly you need ordering versus how much you need to parallelize consumption across multiple consumer instances.
All four types can be used on the same topic simultaneously via different subscription names, since each subscription tracks its own independent state.
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