That's one case. Well, if I get it right, the change log's topic name is bound to applicationId, so what I want to ask is how change log works for scenarios like application upgrade (with new applicationId, I guess). Does the system handle that for user ?
On Mon, May 23, 2016 at 9:21 PM Matthias J. Sax <matth...@confluent.io> wrote: > If I understand correctly, you want to have a non-Kafka-Streams consumer > to read a change-log topic that was written by a Kafka-Streams application? > > That is certainly possible. Kafka is agnostic to Kafka Stream, ie, all > topics are regular topic and can be read by any consumer. > > > -Matthias > > On 05/23/2016 10:48 AM, Manu Zhang wrote: > > Thanks Matthias. Is there a way to allow users to read change logs from a > > previous application ? > > > > On Mon, May 23, 2016 at 3:57 PM Matthias J. Sax <matth...@confluent.io> > > wrote: > > > >> Hi Manu, > >> > >> Yes. If a StreamTask recovers, it will write to the same change log's > >> topic partition. Log compaction is enable per default for those topics. > >> You still might see some duplicates in your output. Currently, Kafka > >> Streams guarantees at-least-once processing (exactly-once processing is > >> on the roadmap though). > >> > >> > >> -Matthias > >> > >> On 05/23/2016 06:10 AM, Manu Zhang wrote: > >>> Hi All, > >>> > >>> I'm new to Kafka Streams and have a question on change log. > >>> If a StreamTask fails and is restarted, will the change log be written > to > >>> the old change log's topic partition ? Is it possible for some change > >> log > >>> topic partition to have duplicate records so that log compaction is > >>> required ? > >>> > >>> Thanks, > >>> Manu Zhang > >>> > >> > >> > > > >
