Strange behavior of a Vb.net application under Stress

Question

User1461970823 posted

I'm having a problem with a system that I maintain.
I downloaded a program (http Rider) to stress my application and happens very strange behavior.
In the macro  I make the login, click on one of the 4 modules, go into a search screen and do the search with the default filters.
While this routine is running for 100 threads with 100 millisecond intervals, make the login on the system and go into another screen that has only one combo. This combo performs a simple procedure in Sql 2008 database with Ado.net (framework 3.5).
I'm on this screen and I just refreshing the screen. Several times this combo receives data from one of the procedures involved in the routine of the stresser. It's random.
I know that if I turn off the pool, by setting pooling to false in the connection string, this problem does not occur.
I've used the Fill, already switched to dataReader and do not use shared methods.
This behavior occurs when public in Release mode. In Debug mode we have no reports of this problem happen.
I don't know how else to investigate.
I have access to the system code.

I hope I was clear in the scenario.
Grateful now.

Answer 1

User197322208 posted

Several times this combo receives data from one of the procedures involved in the routine of the stresser. It's random.

How do you know? What is the code?

Answer 2

User1461970823 posted

I know all the procedures involved in the process and i created a function that log the procedure and the dataTable columns in a text file.

The code that fill the combo is really simple.
This code is my attempt to use a dataReader, but the problem still happens.

Dim dt As DataTable = ExecuteConnection()

With cmbRestaurantes
  .DataSource = dt
  .DataTextField = "vchNome"
  .DataValueField = "EnteJuridico_ID"
  .DataBind()
End With


Private Function ExecuteConnection() As DataTable

        Dim list As New List(Of System.Data.SqlClient.SqlParameter)

        list.Add(New System.Data.SqlClient.SqlParameter("@Usuario_ID", CType(Session("ssObjUsuario"), BLL.bllUsuario).objSchema.Usuario_ID))
        list.Add(New System.Data.SqlClient.SqlParameter("@TipoEnteJuridico_ID", 1))
        list.Add(New System.Data.SqlClient.SqlParameter("@bitAtivo", DBNull.Value))
        list.Add(New System.Data.SqlClient.SqlParameter("@EnteJuridico_Id", DBNull.Value))

        Dim returnDt As New DataTable
        Dim dtReader As SqlDataReader = Nothing

        Using con As SqlConnection = New SqlConnection(Common.getSqlConnection())
            Using cmd As SqlCommand = New SqlCommand("P_SEL_RESTAURANTES_VINCULADOS", con)

                cmd.CommandType = CommandType.StoredProcedure

                For Each param As SqlParameter In list
                    cmd.Parameters.Add(param)
                Next

                con.Open()
                dtReader = cmd.ExecuteReader()

                returnDt.Load(dtReader)


                logData(returnDt, list, con.ConnectionString, cmd.CommandText)
            End Using

        End Using


        Return returnDt

    End Function

Answer 3

User1461970823 posted

For some reason, i publish the same application in another server and the issue did not happen.
I'll investigate the difference between the two servers and post here if i found the reason.

Answer 4

User1461970823 posted

So, i have found my solution. The problem wasn't in the code, but on IIS.
I changed the loadUserProfile, inside pool configurations, to true and my ghost bug was solved.

The reason and how to do this configuration can be found here:

http://blogs.iis.net/bills/archive/2006/10/18/loadUserProfile-and-IIS7-_2D00_-understanding-temporary-directory-failures.aspx

http://blogs.msdn.com/b/vijaysk/archive/2009/03/08/iis-7-tip-3-you-can-now-load-the-user-profile-of-the-application-pool-identity.aspx

Hope help someone else with this post.
Thanks.