I had a similar question, and just watched the video on the confluent.io site about this. >From what I understand idempotence and transactions are there to solve the duplicate writes and exactly once processing, respectively.
Is what you are stating below is that this only works if we produce into a kafka topic and consume from it via a kafka stream, but a regular kafka consumer won't get the guarantee of exactly once processing? Thanks, Chris On Sat, Aug 31, 2019 at 12:29 AM Matthias J. Sax <matth...@confluent.io> wrote: > Exactly-once on the producer will only ensure that no duplicate writes > happen. If a downstream consumer fails, you might still read message > multiple times for all cases (ie, without idempotence, with idempotence > enabled, or if you use transactions). > > Note, that exactly-once is designed for a read-process-write pattern, > but not for a write-read pattern. > > -Matthias > > > > On 8/30/19 1:00 PM, Peter Groesbeck wrote: > > For a producer that emits messages to a single topic (i.e. no single > > message is sent to multiple topics), will enabling idempotency but not > > transactions provide exactly once guarantees for downstream consumers of > > said topic? > > > > Ordering is not important I just want to make sure consumers only > consumer > > messages sent once. > > > >
