Agreed w/ Jason re: compatibility. It seems like such an edge case to actually rely on this and I'd consider the current behavior essentially a bug given how surprising it is. While normally a stickler for compatibility, I think this is a case where its fine to make the change.
-Ewen On Wed, Jul 20, 2016 at 9:48 AM, Jason Gustafson <ja...@confluent.io> wrote: > Hey Vahid, > > Thanks for writing this up. This seems like a nice improvement over the > existing somewhat surprising behavior. Currently if you have a consumer > which changes subscriptions, then you will need to handle separately any > cleanup for assigned partitions for topics which are no longer subscribed. > With this change, the user can handle this exclusively in the > onPartitionsRevoked() callback which seems less error prone. This also > makes it unnecessary for us to do any special handling when autocommit is > enabled since all partitions will still be assigned when we do the final > offset commit prior to rebalancing. The main question mark in my mind is > compatibility, but it seems unlikely that anyone depends on the current > behavior. My hunch is that users probably expect it already works this way, > so from that perspective, it's almost more of a bug fix. > > Thanks, > Jason > > On Tue, Jul 19, 2016 at 5:55 PM, Vahid S Hashemian < > vahidhashem...@us.ibm.com> wrote: > > > Hi all, > > > > We have started a new KIP under > > > > > https://cwiki.apache.org/confluence/display/KAFKA/KIP-70%3A+Revise+Partition+Assignment+Semantics+on+New+Consumer%27s+Subscription+Change > > > > Your feedback is much appreciated. > > > > Regards, > > Vahid Hashemian > > > > > -- Thanks, Ewen
