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 We observed in some cases the isr were outdated: healthy brokers may be 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
