Akka persistence - retrieve processor id from journal

[agourlay]

imported from https://www.assembla.com/spaces/akka/tickets/3892

As discussed here https://groups.google.com/forum/#!topic/akka-user/Y8HNrGqVZ-g, it would be really useful to have an API on the Journal to retrieve the id of processors which have state within the Journal.

[olger]

+1

In a situation with a lot of (Eventsourced)Processors and having a View to store certain (view) state into a database (or other storage), You need to take care of the way connections to these storage are managed, especially when it is used together with cluster sharding.

A single view that is able to proces the events per node (or for multiple nodes) allows for an easy construction of a CQRS style model.

[ktoso]

This query will be one of the example queries in the new Query Side (experimental in 2.4):
#16541

However it means that journals may or may not implement this feature.

[patriknw]

@ktoso is this done (via the query PR)?
The actual impl for leveldb is in #18191

[ktoso]

Yes, thanks for closing.