If there are more partitions than consumers in a group, what could happen?

• A. Some consumers may own multiple partitions
• B. All partitions will be owned by a single consumer
• C. None of the above
• D. Partitions will be reassigned to producers

Answer: (A)

In Kafka, a consumer group is responsible for consuming partitions of topics it subscribes to, and partitions determine the level of parallelism. When there are more partitions than consumers, the group coordinator assigns partitions across the available consumers and, to cover every partition, some consumers end up handling more than one partition. This is expected because there aren’t enough consumers to give each partition its own worker.

So, some consumers may own multiple partitions to ensure all partitions are actively consumed. The idea that all partitions would be owned by a single consumer isn’t the typical outcome of the balanced assignment, and producers don’t own partitions—only consumers in a group do.