Projection event handler missing events

Currently have the command handler and event handler for projections in a single jvm. Unfortunately our projection event handler seems to be skipping events and not updating our projection. When I try to replay this appears to be resolved, but it is hard to trust given I have to be constantly checking if an event was processed or not. Everything I have looked at as far as otel metrics tells me there wasn’t an error it just wasn’t processed.

Hi Jacob,

Could you give me a bit more information about your setup? Are you consuming events directly from your Event Store (e.g. - Axon Server or an RDBMS) or are you consuming these from another method for event distribution (e.g. Kafka or Rabbit)?


Hi Ben,

Given its from within the same service I would assume it would automatically consume from the event store (Postgres based).

Unless there is extra configuration to make that happen. We do have external services using kafka for distribution so maybe thats overriding for everything?


One thing I did notice is in console one of my services shows that it has the processor __axon-kafka-event-publishing-group claimed and one does not. Obviously its due to the processors being named the same. I don’t know how to rename those though.

The most interesting thing I noticed with this is that should only exist if we are using a subscribing producer but both services are set to tracking.

I also know that it had previously been mentioned that kafka is unnecessary even without axon server and with event processors in a separate jvm than the command model. But I haven’t been able to find any examples of this in practice.

Hi Jacob,

We have our bike-rental-demo project which shows running event processors reading directly from the Axon Server event store.

AxonIQ/bike-rental-quick-start: Sample app to show how one can use Axon Framework and Axon Server to go from monolith to microservices (