I believe the event stream (no matter how it is received, i.e. via Akka 
Streams or otherwise) is used to update read-side NoSQL or SQL store(s) 
that handle the queries (or at least they are used for the queries by other 
actors, e.g. an actor handling a request from a Web app).  

For example, the event stream could be used to update a denormalised 
document database, a graph database and an SQL database, each providing 
responses to different types of queries on the read side. 

Cheers,
Ashley.

On Monday, 8 September 2014 15:26:39 UTC+8, Prakhyat Mallikarjun wrote:
>
> 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
>

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