Thanks Neha. It’s a fair point. We don’t need two anymore. There isn’t much to be gained from changing the existing nomenclature, unless people feel strongly about it the word epoch. LeaderEpoch is currently fairly ingrained (spans Zookeeper, the controller, the metadata requests etc). I suggest ditch LeaderGeneration.
I’ll update the KIP. B Ben Stopford Confluent, http://www.confluent.io <http://www.confluent.io/> > On 11 Dec 2016, at 22:30, Neha Narkhede <n...@confluent.io> wrote: > > Good to see this KIP being proposed. Back when I added the epoch to the > replication protocol, we discussed adding it to the log due to the failure > scenarios listed in the KIP but I failed to convince people that it was > worth the effort needed to upgrade the cluster (especially after we asked > people to go through a painful backwards incompatible upgrade for 0.8 :-)) > The lack of including the leader epoch/generation in the log has also been > one of the biggest critiques of Kafka's replication protocol by the > distributed systems community. > > I'm in favor of this work though I think we shouldn't end up with 2 notions > of representing a leader's generation. When we added the epoch, we wanted > to add it to the log but we didn't. Now that we are adding the generation > id to the log, I think we should revisit calling it the epoch at all. Have > you thought about a way to evolve the epoch to the generation id throughout > and what it will take? > > On Sun, Dec 11, 2016 at 4:31 AM Ben Stopford <b...@confluent.io> wrote: > >> Hi All >> >> Please find the below KIP which describes a proposed solution to a couple >> of issues that have been observed with the replication protocol. >> >> In short, the proposal replaces the use of the High Watermark, for >> follower log trunctation, with an alternate Generation Marker. This >> uniquely defines which leader messages were acknowledged by. >> >> >> https://cwiki.apache.org/confluence/display/KAFKA/KIP-101+-+Alter+Replication+Protocol+to+use+Leader+Generation+rather+than+High+Watermark+for+Truncation >> < >> https://cwiki.apache.org/confluence/display/KAFKA/KIP-101+-+Alter+Replication+Protocol+to+use+Leader+Generation+rather+than+High+Watermark+for+Truncation >>> >> >> All comments and suggestions greatly appreciated. >> >> Ben Stopford >> Confluent, http://www.confluent.io <http://www.confluent.io/> >> >> -- > Thanks, > Neha
