RE: [wsdm][UPlat] Transaction

What?

A “unit of work” that consists of multiple actions (typically, an ordered set) invoked against a single resource, the same action applied to multiple resources, or multiple actions against multiple resources. The “unit of work” should be executed once and only once, even if due to transmission failures or other errors, the request may be received multiple times.

One of three outcomes will result from the execution of a transaction:

- all actions against all resources may succeed

- one or more actions may fail and all actions against all resources are rolled back (if roll back is not possible or not supported, then the resources should be reconfigured to an operational, compensory state)

- one or more actions may fail and the resources are left as affected by the actions

A UML diagram describing a transaction model is attached.

Why?

Grouping actions against resources and assuring their execution is very valuable. A manager may request that multiple actions/operations be performed as a single "unit", and that the integrity of the complete/combined request be preserved. For example, it may be important for efficient operation to first shutdown and then failover a jabbering port (an example of multiple, ordered actions against a single resource). It is not correct to failover the port addressing until the shutdown has occurred. And, it is not correct to have the shutdown request arrive multiple times, after the port error has been corrected. Another example of multiple (possibly unordered) actions against a single resource is the setting of two or more management attributes on a resource, where the attributes must be set/reset together in order for the resource to successfully operate. One last example is where an administrator wishes to configure three identical resources using the same configuration settings. This is an example of multiple actions (the setting of multiple attributes) against multiple resources. Again, for successful operation, all three resources must be updated or reset together in order to interoperate.

Note that transactions are being designed into functional/business Web Services. Manageability implementations would simply make use of existing Web Services transactional capabilities.

Andrea

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