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This KIP proposes combining the second and third strategies. The coordinator will maintain a cache to store individual topic hashes. When a topic changes, only its hash will be recalculated. Different groups can retrieve the topic hash from the cache, eliminating the need for the coordinator to recalculate the same hash multiple times. In the record, the coordinator will aggregate all subscribed topic hashes into a single hash per group and store it on disk. This approach minimizes disk usage while efficiently handling changes.

Public Interfaces

ConsumerGroupPartitionMetadataKey / ConsumerGroupPartitionMetadataValue

These types will be deprecated for backward compatibility.

StreamsGroupPartitionMetadataKey / StreamsGroupPartitionMetadataValue / ShareGroupPartitionMetadataKey / ShareGroupPartitionMetadataValue

These types will be deleted, because the coordinator doesn't store topic metadataStream / Share group coordinator has not been GA before 4.1.

ConsumerGroupMetadataValue

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