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Showing content with the highest reputation on 04/19/2018 in all areas

  1. 1 point
    I think I have found a fundamental issue with the DB Toolkit Open connection. It seems to not correctly use connection pooling. The reason I believe it's an issue with LabVIEW and ADODB ActiveX specifically is because the problem does not manifest itself using the ADODB driver in C#. This is better shown with examples. All I am doing in these examples is opening and closing connections and benchmarking the connection open time. Adodb and Oracle driver in LabVIEW. ADODB in C# namespace TestAdodbOpenTime { class Program { static void Main(string[] args) { Stopwatch sw = new Stopwatch(); for (int i = 0; i < 30; i++) { ADODB.Connection cn = new ADODB.Connection(); int count = Environment.TickCount; cn.Open("Provider=OraOLEDB.Oracle;Data Source=FASTBAW;Extended Properties=PLSQLRSet=1;Pooling=true;", "USERID", "PASSWORD", -1); sw.Stop(); cn.Close(); int elapsedTime = Environment.TickCount - count; Debug.WriteLine("RunTime " + elapsedTime); } } } } Output: RunTime 203 RunTime 0 RunTime 0 RunTime 0 RunTime 0 RunTime 0 RunTime 0 RunTime 0 RunTime 0 Notice the time nicely aligns between the LabVIEW code leveraging the .NET driver and the C# code using ADODB. The first connection takes a bit to open then the rest the connection pooling takes over nicely and the connect time is 0. Now cue the LabVIEW ActiveX implementation and every open connection time is pretty crummy and very sporadic. One thing I happened to find out by accident when troubleshooting was if I add a property node on the block diagram where I open a connection, and if I don't close the reference, my subsequent connect times are WAY faster (between 1 and 3 ms). That is what leads me to believe this may be a bug in whatever LabVIEW does to interface with ActiveX. Has anyone seen issues like this before or have any idea of where I can look to help me avoid wrapping up the driver myself?
  2. 1 point
    In the .net code you have it looks like you aren't actually destroying the objects but I think the labview equivalent is -- equivalent to if you called this in the .net version. My guess is that when you get the connection properties in the screenshot you're leaking a reference which prevents overall destruction of the main connection object thus leading to faster subsequent runs. What happens if you change your first code so that you wait to close the connections until after you open all of them? Does that go fast?


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