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What is the AF SDK equivalent for PI API Snapshot functions

Question asked by Noga on Jun 19, 2018
Latest reply on Jun 20, 2018 by John Messinger

I am quite new to the AF-SDK, and I have few questions I would very much like to be clarified of.

First, I would like to know ,what are the AF-SDK options for getting a continuous flow of data from pi-archive server through the events/notifications mechanism-

To be more precise, I would like to understand:

What is the AF SDK equivalent for the PI API snapshot functions: pisn_evmestablish() and pisn_evmexceptions()?  Is it the AFDataPipe class?


Concerning the AFDataPipe class, as described in the OsiSoft Tech Support documentation: 

“ There are two ways to get the data change events:

a) direct GetUpdateEvents method to get events;

b) through IObserver of AFDataPipeEvent. The IObserver pattern provides significant performance improvement over direct GetUpdateEvents method for high throughput scenario.

Application will have to implement the IObserver and register the IObserver with the data pipe via the Subscribe(IObserver<AFDataPipeEvent> ) method.”


What I am not clear about is: What exactly is the difference between AFDataPipeEvent()  vs GetObserverEvents() methods?


Also, I see this class have the properties: AFDataPipeType.Snapshot and AFDataPipeType.TimeSeries.

What is the difference between these two properties?