Threads in WCF service
- by dragonfly
Hi,
there is a piece of code:
class WCFConsoleHostApp : IBank
{
private static int _instanceCounter;
public WCFConsoleHostApp ()
{
Interlocked.Increment(ref _instanceCounter);
Console.WriteLine(string.Format("{0:T} Instance nr " + _instanceCounter + " created", DateTime.Now));
}
private static int amount;
static void Main(string[] args)
{
ServiceHost host = new ServiceHost(typeof(WCFConsoleHostApp));
host.Open();
Console.WriteLine("Host is running...");
Console.ReadLine();
}
#region IBank Members
BankOperationResult IBank.Put(int amount)
{
Console.WriteLine(string.Format("{0:00} {1}", Thread.CurrentThread.ManagedThreadId, Thread.CurrentThread.IsThreadPoolThread) + " Putting...");
WCFConsoleHostApp.amount += amount;
Thread.Sleep(20000);
Console.WriteLine(string.Format("{0:00} {1}", Thread.CurrentThread.ManagedThreadId, Thread.CurrentThread.IsThreadPoolThread) + " Putting done");
return new BankOperationResult { CurrentAmount = WCFConsoleHostApp.amount, Success = true };
}
BankOperationResult IBank.Withdraw(int amount)
{
Console.WriteLine(string.Format("{0:00} {1}", Thread.CurrentThread.ManagedThreadId, Thread.CurrentThread.IsThreadPoolThread) + " Withdrawing...");
WCFConsoleHostApp.amount -= amount;
Thread.Sleep(20000);
Console.WriteLine(string.Format("{0:00} {1}", Thread.CurrentThread.ManagedThreadId, Thread.CurrentThread.IsThreadPoolThread) + " Withdrawing done");
return new BankOperationResult { CurrentAmount = WCFConsoleHostApp.amount, Success = true };
}
#endregion
}
My test client application calls that service in 50 threads (service is PerCall). What I found very disturbing is when I added Thread.Sleep(20000) WCF creates one service instance per second using different thread from pool.
When I remove Thread.Sleep(20000) 50 instances are instanciated straight away, and about 2-4 threads are used to do it - which in fact I consider normal.
Could somebody explain why when Thread.Sleep causes those funny delays in creating instances?
