Sean Quah created KAFKA-18688: --------------------------------- Summary: Uniform homogeneous assignment is not always stable Key: KAFKA-18688 URL: https://issues.apache.org/jira/browse/KAFKA-18688 Project: Kafka Issue Type: Bug Components: group-coordinator Reporter: Sean Quah
The uniform homogeneous assignor assigns partitions to group members which have identical subscriptions. When the number of partitions is not divisible by the number of members, some members will end up with 1 more partition than others. The assignor iterates over members and chooses the first {{partitions % members}} members to have the extra partition. Even when the existing assignment is balanced, the assignor can decide that a different set of members should have the extra partition, due to the iteration order. This means that when a static member is replaced and the assignment is recomputed, it may gain or lose a single partition. -- This message was sent by Atlassian Jira (v8.20.10#820010)