> On Jul 26, 2018, at 11:09 PM, Guozhang Wang <wangg...@gmail.com> wrote: > > Hi Boyang, > > Thanks for the proposed KIP. I made a pass over the wiki and here are some > comments / questions: > > 1. In order to preserve broker compatibility, we need to make sure the > broker version discovery logic can be integrated with this new logic. I.e. > if a newer versioned consumer is talking to an older versioned broker who > does not recognize V4, the client needs to downgrade its JoinGroupRequest > version to V3 and not setting the member-id specifically. You can take a > look at the ApiVersionsRequest and see how to work with it. > > 2. There may exist some manners to validate that two different clients do > not send with the same member id, for example if we pass along the > host:port information from KafkaApis to the GroupCoordinator interface. But > I think this is overly complicated the logic and may not worthwhile than > relying on users to specify unique member ids.
Boyang, Thanks for the KIP! How will the algorithm behave if multiple consumers provide the same member id? -James > 3. Minor: you would need to bumping up the version of JoinGroupResponse to > V4 as well. > > 4. Minor: in the wiki page, you need to specify the actual string value for > `MEMBER_ID`, for example "member.id". > > 5. When this additional config it specified by users, we should consider > setting the default of internal `LEAVE_GROUP_ON_CLOSE_CONFIG` to false, > since otherwise its effectiveness would be less. > > > Guozhang > > > >> On Thu, Jul 26, 2018 at 9:20 PM, Boyang Chen <bche...@outlook.com> wrote: >> >> Hey friends, >> >> >> I would like to open a discussion thread on KIP-345: >> >> https://cwiki.apache.org/confluence/display/KAFKA/KIP-345%3A >> +Reduce+multiple+consumer+rebalances+by+specifying+member+id >> >> >> This KIP is trying to resolve multiple rebalances by maintaining the >> consumer member id across rebalance generations. I have verified the theory >> on our internal Stream application, and it could reduce rebalance time to a >> few seconds when service is rolling restart. >> >> >> Let me know your thoughts, thank you! >> >> >> Best, >> >> Boyang >> > > > > -- > -- Guozhang
