Просто запустите его в другой ветке так:
'Starts execution of the proc
Protected Sub Button1_Click(sender As Object, e As System.EventArgs) Handles Button1.Click
Dim t As New Threading.Thread(AddressOf DoWork)
t.Start()
End Sub
Private Sub DoWork()
Using c As New SqlConnection(ConfigurationManager.ConnectionStrings("ConnectionString").ConnectionString)
c.Open()
Dim command = New SqlCommand("LongTest", c)
command.CommandType=Data.CommandType.StoredProcedure
command.CommandTimeout = 0
command.ExecuteNonQuery()
End Using
End Sub
Вот sp, который я использовал для моего теста:
create PROCEDURE dbo.LongTest
AS
BEGIN
WaitFor Delay '00:00:30' --wait for 30 seconds before doing anything
insert into TableImageTest(image)
values(null)
END