domain driven design - How can CQRS contribute to more scalable applications -

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lately i've been reading lot on cqrs architecture. 1 of foremost points stated on why 1 should use cqrs scalability.

now don't quite understand how can work.

let's have typical cqrs application design.

  • two datastores
  • one command side
  • one query side
  • when command has been processed event send update second datastore

it's stated having datastore querying , 1 handling commands make application more scalable. how can work if second datastore stores event data needs respond query requests , needs update iteself based on incoming events ?

why not have 1 datastore commands stored , query side can re-use stored data fetching it's result data ?

you might find interesting read old blog post greg young himself, explains cqrs is.

cqrs not having 2 different stores, but, stated on greg's article:

cqrs creation of 2 objects there one. separation occurs based upon whether methods command or query

what describe here more event sourcing.

now question: how can cqrs contribute more scalable applications? greg answers well:

cqrs allows host 2 services differently eg: can host read service on 25 servers , write service on two. processing of commands , queries fundamentally asymmetrical, , scaling services symmetrically not make lot of sense.

that's it!


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