Hi Prakhyat,

On 24 September 2014 at 14:51:06, Prakhyat Mallikarjun ([email protected]) 
wrote:

Team,

We are taking CQRS/DDD/Event sourcing approach to build our app.

Write side makes use of PersistentView to push events from write side to STATE 
at read side.


If you only want to read the events and push them, you could do this without 
the PersistentView.

But this happens asynchronously as PersistentView pulls events from its 
PersistentActor at configured interval. The PersistentView  is the hard link 
between read and write side. If anything happens to this link, the read and 
write will be out of sync.


Yes, that is the price you pay for separating the write side and the read side. 
More on the choices you can make are described here  
http://codebetter.com/gregyoung/2010/02/20/cqrs-and-cap-theorem/

If PersistentView fails or is down, the events will be keep on piling up at 
write side and query side will be in out of sycn with write side.

How to make sure the link is durable? The read and write side are always kept 
in sync and consistent. 


This is always a tradeoff. You have to decide what kind if guarantees you are 
willing to provide. If everything needs to be completely consistent at all 
times, then you can't separate the read and write side.

B/


-Prakhyat M M
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