Hi Jie, If you see frequent changes in the ISR for some partitions, you can follow the recommendation here<https://cwiki.apache.org/confluence/display/KAFKA/FAQ#FAQ-HowtoreducechurnsinISR?WhendoesabrokerleavetheISR?>to address that.
Thanks, Neha On Wed, Mar 26, 2014 at 11:11 AM, Guozhang Wang <wangg...@gmail.com> wrote: > Hello Jie, > > Yes, the ISR shrinking is handled in a background thread which will > periodically check the status of each replica and probably kick them out of > ISR if they are not in-sync with the leader. You can tune the frequency in > this broker config: > > replica.lag.time.max.ms > > The ISR expanding is handled by the leader of the partition whenever it > receives a fetch request from the followers, checking if the follower has > already caught up. > > Guozhang > > > On Tue, Mar 25, 2014 at 10:06 PM, Jie Li <jay23j...@gmail.com> wrote: > > > Hello, > > > > We observed in some cases the isr were outdated: healthy brokers may be > > missing from isr, or dead brokers may still stay in isr for a while. My > > guess is the list of isr is only updated upon a few events, e.g. when a > > message is written to the partition, or when the brokers come online? > > > > Thanks, > > Jie > > > > > > -- > -- Guozhang >