/// <summary>
/// Have T1 and T2 read R1, both shall get the result immediately.
/// Have T1, T2 both write R2 concurrently, The result shall be correct. Demo locks and two transaction runs concurrently.
/// </summary>
public void ConcurrentTransactions()
{
StartUp();
Transaction t1 = WorkflowControl.Start();
Transaction t2 = WorkflowControl.Start();
Assert.AreEqual(WorkflowControl.QueryCar(t1, "Vegas"), WorkflowControl.QueryCar(t2, "Vegas"));
AutoResetEvent sync1 = new AutoResetEvent(false);
AutoResetEvent sync2 = new AutoResetEvent(false);
ThreadPool.QueueUserWorkItem(o =>
{
WorkflowControl.AddCars(t1, "Seattle", 1, 3);
WorkflowControl.Commit(t1);
sync1.Set();
});
ThreadPool.QueueUserWorkItem(o =>
{
WorkflowControl.AddCars(t2, "Seattle", 2, 3);
WorkflowControl.Commit(t2);
sync2.Set();
});
// here is just to make sure t2 commits before t1, so the price will be 2.
sync1.WaitOne();
sync2.WaitOne();
string actual = PrintCars();
Assert.AreEqual("Vegas,1,3;NewYork,10,30;Seattle,3,3;", actual);
}