I made the mistake of setting up my lookup tables to be populated from a tracking processor from within the same jvm. I recognize the appropriate usage is with a subscribing event processor. That being said would I need to reset my lookup tables if I change the event processor to subscribing?
Hi,
I am not an Axon developer, but I might have some input for this topic, as we have done similar migrations.
Moving from tracking to subscribing is a little bit difficult due to two reasons:
- You don’t exactly know whether the processor is up to date. So simply switching to a subscribing processor means that you might loose data.
- You can’t replay a subscribing event processor (there are…ways to do that, but officially it is not supported)
I recommend to check during the migration that your event processor is actually up-to-date. Select the token in the token store for the processor in question, deserialize them and check whether they are up-to-date regarding the event processor. This becomes even more difficult in case of the Axon server. If this is the case, you can continue and switch to a subscribing processor. Remove the superfluous tokens from the token store.
If this is not possible: Write a manual migration class that deletes the lookup tables, reads the whole event stream and processes it manually to rebuild the lookup tables.
Best regards
Nils
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