CQRS sagas - did I understand them right?

Question

I\'m trying to understand sagas, and meanwhile I have a specific way of thinking of them - but I am not sure whether I got the idea right. Hence I\'d like t

Answer 1

The term saga is commonly used in discussions of CQRS to refer to a piece of code that coordinates and routes messages between bounded contexts and aggregates. However, for the purposes of this guidance we prefer to use the term process manager to refer to this type of code artifact. There are two reasons for this: There is a well-known, pre-existing definition of the term saga that has a different meaning from the one generally understood in relation to CQRS. The term process manager is a better description of the role performed by this type of code artifact. Although the term saga is often used in the context of the CQRS pattern, it has a pre-existing definition. We have chosen to use the term process manager in this guidance to avoid confusion with this pre-existing definition. The term saga, in relation to distributed systems, was originally defined in the paper "Sagas" by Hector Garcia-Molina and Kenneth Salem. This paper proposes a mechanism that it calls a saga as an alternative to using a distributed transaction for managing a long-running business process. The paper recognizes that business processes are often comprised of multiple steps, each of which involves a transaction, and that overall consistency can be achieved by grouping these individual transactions into a distributed transaction. However, in long-running business processes, using distributed transactions can impact on the performance and concurrency of the system because of the locks that must be held for the duration of the distributed transaction.

reference: http://msdn.microsoft.com/en-us/library/jj591569.aspx