Hi Roland, Puff..I am relaxed now after reading your response.
I had this confusion from long time. Looking forward to your updates and changes. We are using CQRS and this piece is critical to our design and implementation. Now I have the complete context to your conclusion post and can relate to it. Thanks. -Prakhyat M M On Monday, 8 September 2014 13:12:46 UTC+5:30, rkuhn wrote: > > Hi Prakhyat, > > the misunderstanding stems from the fact that there are two layers of > querying involved. User code asks the read-side for current information, > which is the query you mean, but that is not what we are talking about in > Akka Persistence. Akka does not really care how you structure your data for > user queries since there are a multitude of possible use-cases and > solutions to that. What we do care about is only how Actor Persistence > works and how that meshes with a CQRS system in general. > > Therefore the Query mentioned in “The Conclusion” is only about how the > read-side extracts the data from the Journal, nothing more. The read-side > will consume the stream of updates (events) and use them to maintain the > current state which is then queried by the user. > > The term Query is a very generic one, but unfortunately it also is the > correct one for both kinds of uses. > > Regards, > > Roland > > 8 sep 2014 kl. 09:26 skrev Prakhyat Mallikarjun <[email protected] > <javascript:>>: > > Team, > > I am unable to decode Akka Persistence on the Query Side: The Conclusion( > https://groups.google.com/forum/#!topic/akka-user/MNDc9cVG1To) entirely. > > Correct me if I am wrong, the discussion hints at making use of akka > streams for querying in CQRS systems. > > I want to understand how history of events can be useful for querying. > Querying I mean, business specific querying or complex reporting spanning > multiple aggreagate roots. > > As I understand any querying will require *current state*. I am unable to > fathom, how streams of events can be used for responding to queries. > > Will queries, fetch the events from streams, replay them in run time and > prepare state? > > Please provide a use case or practical example to make us understand. If > your example can include multiple aggregate roots, it will be even better. > > -Prakhyat M M > > -- > >>>>>>>>>> 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/d/optout. > > > > > *Dr. Roland Kuhn* > *Akka Tech Lead* > Typesafe <http://typesafe.com/> – Reactive apps on the JVM. > twitter: @rolandkuhn > <http://twitter.com/#!/rolandkuhn> > > -- >>>>>>>>>> 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.
