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Matthias J. Sax commented on KAFKA-16514: ----------------------------------------- Thanks for the input. I was not reviewing/voting the original KIP nor the PR. Thus, I did just assume there was some mentioning about static groups... As there is nothing about it in the KIP as you pointed out, I did some digging and the PR reveals why it's only implemented for static members: [https://github.com/apache/kafka/pull/12035#discussion_r858263213] We use admin client "removeMembersFromConsumerGroup" which only works for static member, as it take the consumers `group.instance.id` as input. It seems it was a pragmatic approach... Re-reading the KIP discussion it seems that making it work for regular members would require a change in the consumer API, and thus would have been a larger scope KIP (and the idea was to keep the KIP scope limited). Thus, while we might not need a KIP for Kafka Streams, we would need one for the consumer to allow KS to use this newly added API... In the mean time, we could still to a small PR to update the JavaDocs to call out the current limitation (what will not make it a public contract IMHO, so after we get a consumer KIP we can still address this limitation w/o another KIP). Thoughts? > Kafka Streams: stream.close(CloseOptions) does not respect options.leaveGroup > flag. > ----------------------------------------------------------------------------------- > > Key: KAFKA-16514 > URL: https://issues.apache.org/jira/browse/KAFKA-16514 > Project: Kafka > Issue Type: Bug > Components: streams > Affects Versions: 3.7.0 > Reporter: Sal Sorrentino > Priority: Minor > > Working with Kafka Streams 3.7.0, but may affect earlier versions as well. > When attempting to shutdown a streams application and leave the associated > consumer group, the supplied `leaveGroup` option seems to have no effect. > Sample code: > {code:java} > CloseOptions options = new CloseOptions().leaveGroup(true); > stream.close(options);{code} > The expected behavior here is that the group member would shutdown and leave > the group, immediately triggering a consumer group rebalance. In practice, > the rebalance happens after the appropriate timeout configuration has expired. > I understand the default behavior in that there is an assumption that any > associated StateStores would be persisted to disk and that in the case of a > rolling restart/deployment, the rebalance delay may be preferable. However, > in our application we are using in-memory state stores and standby replicas. > There is no benefit in delaying the rebalance in this setup and we are in > need of a way to force a member to leave the group when shutting down. > The workaround we found is to set an undocumented internal StreamConfig to > enforce this behavior: > {code:java} > props.put("internal.leave.group.on.close", true); > {code} > To state the obvious, this is less than ideal. > Additional configuration details: > {code:java} > Properties props = new Properties(); > props.put(StreamsConfig.APPLICATION_ID_CONFIG, "someApplicationId"); > props.put( > StreamsConfig.BOOTSTRAP_SERVERS_CONFIG, > "localhost:9092,localhost:9093,localhost:9094"); > props.put(StreamsConfig.REPLICATION_FACTOR_CONFIG, 3); > props.put(StreamsConfig.NUM_STANDBY_REPLICAS_CONFIG, 1); > props.put(StreamsConfig.NUM_STREAM_THREADS_CONFIG, numProcessors); > props.put(StreamsConfig.PROCESSING_GUARANTEE_CONFIG, > StreamsConfig.EXACTLY_ONCE_V2);{code} > -- This message was sent by Atlassian Jira (v8.20.10#820010)