PI SDK affecting other users logged when one requests a TREND

Discussion created by snepes on Apr 23, 2014
Latest reply on Apr 29, 2014 by Marcos Vainer Loeff

Hello Friends!

I'm having performance issues with the PI SDK affecting other users logged when one requests a TREND!

Our web application was created to provide information for monitoring "Turbo machines" of Oil Rigs.

It makes access to the PI Server through PI SDK C #.

The current version of the system entered production in 2012 and until the beginning of 2014 had no reported problem. Ie, the application was very stable.

But now every time a customer requested a Graphic (Trend) with a period of 1 year (720 points),
while the "PI Server" did not answer this request (which is really heavy) the system starts
to get very slow for everyone other users logged into machines and different locations.

The application only to get back quickly after the Graph (TREND) is created on the screen and feature releases.

In this scenario we have made several attempts to solve the problem between them try to change the architecture of connection with the "PI SERVER".

As the documentation OSISoft, our application, generated only ONE INSTANCE (SINGLETON) for all application.
So try switching to a ONE INSTANCE per user. But this strategy left the system even slower.

So this week we discovered important information.

In the same period where the problems started was installed a "New Version" in the "PI Server" (PI 2012).
And a professional who has worked in OSISoft said that this new version there is a "Processing Limit" by Application.

And to confirm this thesis we could clearly see this new "processing limit" also in PI EXCEL.

We managed to reproduce the problem with 2 calls made while using the IP EXCEL.

To reproduce the same symptom of the web application, we did the following:

- The first call was made through a Trend 1 year 8 TAGS
- The second call was made shortly after the first via a Trend 30 days with 8 TAGS

The result was that the second call was extremely slow while being processed first.
To confirm our argument, we isolated only the second call and it responded instantly.


1) There is even this "Limit Processing" by application "?

2) It can be changed only for this application?

3) What are the parameters need to be changed? And what is the impact to other applications using the same server?

NOTE: This problem does not happen when using the old and discontinued DLL (PIApi).