Thanks Martin and Patrik. That makes sense but I have a number of views that aggregate data in different ways. If I need to have a one to one correspondence between Views and Processors, it seems like I would need to tightly couple the creation of those Views to the Processors (or their supervisors). This would tightly link these two parts of the application when otherwise the processors don't need to have any knowledge of the views. Am I going about this the wrong way?
On Friday, March 7, 2014 1:39:52 AM UTC-6, Patrik Nordwall wrote: > > > > > On Thu, Mar 6, 2014 at 7:01 PM, Mike <[email protected] <javascript:>>wrote: > >> Using an in memory projection seems to work great. The only limitation >> I've run into (which may be just a limitation in my understanding ...) is >> that a view can only monitor the event stream for a single processor. I >> require a view to aggregate state across a large number of processors >> > > Can't you achieve this by having many one-to-one Views that forwards the > events to one aggregator actor? > > >> so I've resorted to using a pub/sub mechanism. But is there a mechanism >> or design to support a view monitoring a group of processors - for instance >> via an ActorPath instead of a processorId? >> >> >> On Thursday, March 6, 2014 10:07:16 AM UTC-6, Ryan Bair wrote: >>> >>> Thank you both. >>> >>> On Thursday, March 6, 2014 2:13:48 AM UTC-5, Patrik Nordwall wrote: >>>> >>>> >>>> >>>> >>>> On Thu, Mar 6, 2014 at 8:08 AM, Martin Krasser >>>> <[email protected]>wrote: >>>> >>>>> Hi Ryan, >>>>> >>>>> >>>>> On 05.03.14 21:35, Ryan Bair wrote: >>>>> >>>>> I'm working on a project where I would like to retain a history of >>>>> actions performed against an entity and then leverage that history for >>>>> business (what actions led the user to do X) as well as providing the >>>>> user >>>>> with information about past actions. >>>>> >>>>> Event Sourcing seems like it would provide a good way to accomplish >>>>> this as the events are produced and stored as a regular part of the >>>>> application flow, removing the need to do separate bookkeeping. I'm >>>>> really >>>>> impressed by Martin's work on the new Persistence module (and >>>>> Eventsourced >>>>> before it) and would like to move in that direction. However, I don't see >>>>> a >>>>> way to query the `journal` other than through recovery. >>>>> >>>>> Does it make sense to grow Persistence in this direction, or is there >>>>> a better way to tackle what I am attempting? Perhaps simply querying the >>>>> underlying data store directly? >>>>> >>>>> >>>>> Generating query/read models (by projecting an event stream onto an >>>>> in-memory data structure, tables in a database, or whatever) is an >>>>> application-level concern. Akka-persistence is not meant to be a database >>>>> with a query interface. Seems that Datomic is closer to what you're >>>>> looking >>>>> for. >>>>> >>>>> Just as a point of clarification, I'm looking to query the events >>> themselves, not the resulting state. >>> >>>> >>>> I agree, and would like to add that you can use a persistent View to >>>> replicate the event stream to the query side, and there store a >>>> representation that is optimal for these queries (e.g. in sql database). >>>> >>>> /Patrik >>>> >>>> >>> I'm thinking I'll go this way and query the database directly. I might >>> make a JDBC/slick journal implementation and use database views for the >>> queries. >>> >>>> >>>>> -- >>>>> >>>>>>>>>> Read the docs: http://akka.io/docs/ >>>>> >>>>>>>>>> Check the FAQ: http://akka.io/faq/ >>>>> >>>>>>>>>> Search the archives: https://groups.google.com/ >>>>> group/akka-user >>>>> --- >>>>> You received this message because you are subscribed to the Google >>>>> Groups "Akka User List" group. >>>>> To unsubscribe from this group and stop receiving emails from it, send >>>>> an email to [email protected]. >>>>> To post to this group, send email to [email protected]. >>>>> Visit this group at http://groups.google.com/group/akka-user. >>>>> For more options, visit https://groups.google.com/groups/opt_out. >>>>> >>>>> >>>>> -- >>>>> Martin Krasser >>>>> >>>>> blog: http://krasserm.blogspot.com >>>>> code: http://github.com/krasserm >>>>> twitter: http://twitter.com/mrt1nz >>>>> >>>>> -- >>>>> >>>>>>>>>> Read the docs: http://akka.io/docs/ >>>>> >>>>>>>>>> Check the FAQ: http://akka.io/faq/ >>>>> >>>>>>>>>> Search the archives: https://groups.google.com/ >>>>> group/akka-user >>>>> --- >>>>> You received this message because you are subscribed to the Google >>>>> Groups "Akka User List" group. >>>>> To unsubscribe from this group and stop receiving emails from it, send >>>>> an email to [email protected]. >>>>> To post to this group, send email to [email protected]. >>>>> Visit this group at http://groups.google.com/group/akka-user. >>>>> For more options, visit https://groups.google.com/groups/opt_out. >>>>> >>>> >>>> >>>> >>>> -- >>>> >>>> Patrik Nordwall >>>> Typesafe <http://typesafe.com/> - Reactive apps on the JVM >>>> Twitter: @patriknw >>>> >>>> -- >> >>>>>>>>>> Read the docs: http://akka.io/docs/ >> >>>>>>>>>> Check the FAQ: >> http://doc.akka.io/docs/akka/current/additional/faq.html >> >>>>>>>>>> Search the archives: https://groups.google.com/group/akka-user >> --- >> You received this message because you are subscribed to the Google Groups >> "Akka User List" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to [email protected] <javascript:>. >> To post to this group, send email to [email protected]<javascript:> >> . >> Visit this group at http://groups.google.com/group/akka-user. >> For more options, visit https://groups.google.com/groups/opt_out. >> > > > > -- > > Patrik Nordwall > Typesafe <http://typesafe.com/> - Reactive apps on the JVM > Twitter: @patriknw > > -- >>>>>>>>>> Read the docs: http://akka.io/docs/ >>>>>>>>>> Check the FAQ: >>>>>>>>>> http://doc.akka.io/docs/akka/current/additional/faq.html >>>>>>>>>> Search the archives: https://groups.google.com/group/akka-user --- You received this message because you are subscribed to the Google Groups "Akka User List" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/akka-user. For more options, visit https://groups.google.com/d/optout.
