Hi David, Thanks for the clarification. For the two points you shared:
1. I think the key point is that Connect handles this via a separate set of classes - not the Consumer. 2. Can we make it explicit in the KIP that we will migrate this Connect usage to the new rebalance protocol by default in 5.0? In addition, I wonder if it's a good idea to deprecate the classic consumer in 4.3 - isn't that a bit aggressive? Perhaps deprecation should wait until KIP-848 is more widely used. We can still encourage folks to try the consumer group protocol. I think a reasonable target for actual deprecation would be a 4.x release roughly a year from now. Ismael On Tue, Jan 27, 2026 at 7:56 AM David Jacot via dev <[email protected]> wrote: > Ismael, > > We need to discuss two cases for Connect: > > 1) Connect uses the classic rebalance protocol to assign its tasks within a > Connect cluster. This will keep working until we figure out a plan to > migrate this part to another protocol (e.g. Connect protocol following > Streams protocol). This is completely orthogonal from the Consumer. > > 2) Connect uses Consumers in sources/sinks to read from topics. Those > consumers can use the consumer rebalance protocol without any issues. They > can just follow the upgrade path and use the new protocol when the config > changes. > > This means that in 6.0, Connect's Consumer will use the new rebalance > protocol whereas Connect's runtime will continue to use the classic > protocol to distribute its tasks. > > Lianet, we should perhaps clarify this in the KIP. > > Best, > David > > > > On Tue, Jan 27, 2026 at 4:27 PM Ismael Juma <[email protected]> wrote: > > > Lianet, > > > > Thanks for the KIP. I think this is a desirable goal, but it seems > > premature without a plan for Connect. Removing the config for regular > users > > while allowing it for Connect seems problematic. While we figure the > > details of that and the deprecation story for the classic rebalance > > protocol, we could still agree to a log line during start-up recommending > > `classic` users to switch to the switch to `consumer` (after appropriate > > testing). > > > > Ismael > > > > On Thu, Jan 22, 2026 at 2:05 PM Lianet Magrans <[email protected]> > wrote: > > > > > Hello, > > > > > > I would like to start the discussion for KIP-1274. This KIP proposes a > > > phased plan to drive a smooth evolution of Java client consumer > > > applications towards the next generation of the rebalance protocol > > > > > > Here is the KIP: > > > > > > > > > https://cwiki.apache.org/confluence/display/KAFKA/KIP-1274%3A+Deprecate+and+remove+support+for+Classic+rebalance+protocol+in+KafkaConsumer > > > > > > Looking forward to hearing from you, > > > > > > Thanks! > > > Lianet > > > > > >
