The downside of it, though, is that although it "hides" this from most of the users needing to be aware of it, by default session timeout i.e. the rebalance timeout is 10 seconds which could arguably too long.
Guozhang On Thu, Mar 23, 2017 at 10:12 AM, Guozhang Wang <wangg...@gmail.com> wrote: > Just throwing another alternative idea here: we can consider using the > rebalance timeout value which is already included in the join request > protocol (and on the current Java client it is always written as the > session timeout value), that the first member joining will always force the > coordinator to wait that long. By doing this we do not need to bump up the > protocol either. > > > Guozhang > > On Thu, Mar 23, 2017 at 5:49 AM, Damian Guy <damian....@gmail.com> wrote: > >> Hi Ismael, >> >> Mostly to avoid the protocol bump. >> >> I agree that it may be difficult to choose the right delay for all >> consumer >> groups, but we wanted to make this something that most users don't really >> need to think about, i.e., a small enough default delay that works in the >> majority of cases. However it would be much more flexible as a consumer >> config, which i'm happy to pursue if this change is worthy of a protocol >> bump. >> >> Thanks, >> Damian >> >> On Thu, 23 Mar 2017 at 12:35 Ismael Juma <ism...@juma.me.uk> wrote: >> >> > Thanks for the KIP, Damian. It makes sense to avoid multiple rebalances >> > during start-up. One issue with having this as a broker config is that >> it >> > may be difficult to choose the right delay for all consumer groups. Can >> you >> > elaborate a little more on why the first alternative (add a consumer >> > config) was rejected? We bump protocol versions regularly (when it makes >> > sense), so it would be good to get a bit more detail. >> > >> > Thanks, >> > Ismael >> > >> > On Thu, Mar 23, 2017 at 12:24 PM, Damian Guy <damian....@gmail.com> >> wrote: >> > >> > > Hi All, >> > > >> > > I've prepared a KIP to add a configurable delay to the initial >> consumer >> > > group rebalance. >> > > >> > > Please have look here: >> > > https://cwiki.apache.org/confluence/display/KAFKA/KIP- >> > > 134%3A+Delay+initial+consumer+group+rebalance >> > > >> > > Thanks, >> > > Damian >> > > >> > > BTW, i apologize if this appears twice. Seems the first one may have >> not >> > > made it. >> > > >> > >> > > > > -- > -- Guozhang > -- -- Guozhang
