Calling PI-SDK from a C# ASP.Net Web Service

Discussion created by tinklerj on Jun 29, 2012
Latest reply on Aug 1, 2012 by tinklerj

From reading some other threads in this forum, it seems that accessing PI-SDK from an MTA multi-threaded application can be very expensive for some calls (because PI-SDK is an STA object so there is cross-thread marshalling).  So the recommendation when using C# (which uses the MTA model by default) is to use the [STAThread] attribute on the main/thread entry points.


However, if I am creating an ASP.Net Web service, IIS creates the threads (in a pool) and calls my Web methods inside them so I can't make the threads STA.  This may lead to poor performance when calling PI-SDK - essentially serializing all SDK calls, so I can't use parallelism or async calls to improve performance.


For ASPX pages I read that you can put "AspCompat=true" in the Page directive of the markup file, which makes it use the STA threading model,but sadly an ASMX Web service only has the WebService directive which doesn't support this.


<%@ WebService Language="C#" CodeBehind="MyWS.asmx.cs" Class="MyWeb.MyWS" %>


Do you think the "hack" described in this article would help?  Anyone know an easier way to use PI-SDK from a web service?