Change to Persistent Query from deprecated PersistentView

Question

I'm using Akka Persistence, with LevelDB as storage plugin, in an application written in Scala. On the query-side, the current implementation uses PersistentView, which polls messages from a PersistentActor's journal by just knowing the identifier of the actor.

Now I've learned that PersistentView is deprecated, and one is encouraged to use Persistent Query instead. However, I haven't found any thorough description on how to adapt the code from using PersistentView to support the preferred Persistence Query implementation.

Any help would be appreciated!

Answer 1

From the 2.4.x-to-2.5.x migration guide:

Removal of PersistentView

After being deprecated for a long time, and replaced by Persistence Query PersistentView has now been removed.

The corresponding query type is EventsByPersistenceId. There are several alternatives for connecting the Source to an actor corresponding to a previous PersistentView actor which are documented in Integration.

The consuming actor may be a plain Actor or an PersistentActor if it needs to store its own state (e.g. fromSequenceNr offset).

Please note that Persistence Query is not experimental/may-change anymore in Akka 2.5.0, so you can safely upgrade to it.