Hi Cédric I do not know how the topology names are chosen, but provided that you didn't change any of the topology then new topics will not be created or require alteration.
If you modify the topology then the naming can indeed change, but it would then create a new internal topic and there would be no compatibility issue. It could very well be that your topology was modified in such a way that another, different internal topic is attempting to register an incompatible schema. In this case though, I would expect that the error information returned from the schema registry registration process to highlight exactly what the failure is. It has been a while since we run into one of these so I could be wrong on that front though. My recommendation to you is to create a simple "InternalSerde" for your Avro classes used in internal topics, such that you do *not* register them to the schema registry. I have found that registering internal topics to the schema registry turns it into a garbage dump and prevents developers from making independent changes to their internal schemas. The rule of thumb we use is that we only register schemas to the schema registry when the events leave the application's bounded context - ie: final output events only. Hope this helps, Adam On Wed, Aug 8, 2018 at 11:14 AM, Cedric BERTRAND < bertrandcedric....@gmail.com> wrote: > Within the Kafka Stream topology, internal topic are created. > For this internal topics, schema avro for key and value are registered into > schema registry. > > For the topic internal-MYAPPS-KSTREAM-KEY-SELECT-0000000099-repartition, I > have 2 subjects into schema registry : > - internal-MYAPPS-KSTREAM-KEY-SELECT-0000000099-repartition-key > - internal-MYAPPS-KSTREAM-KEY-SELECT-0000000099-repartition-value > > My questions are : > > How Kafka create the internal topology name (how the suffix number is > changed) ? > > When if I change the processing into the toplogy => change in the DAG ? > - If I have a name with 0000000099, do I have the same number after a > modification of the topology ? > - If not, is Kafka Stream allowed to use an already used number ? > > > I ask this question because I have an incompatible schema on an internal > topic and from my point of view, no changes have been made on the schema. > The only change is a modification on the topology which change the DAG and > maybe the name of internal topic. > > > Thanks for your time, > > Cédric >
