Yesterday I looked at the overhead associated with throwing an exception. Driving into work today, I wondering, "what's the cost involved in creating the exception object?"

So I added this method:

public sealed class Methods
{
    public void DoGood()
    {
    }
    
    public void DoBad()
    {
        throw new NotImplementedException();
    }

    public void DoSomething()
    {
        var exception = new NotImplementedException();
    }
}

And added it to the timings:

private static void TimeExceptions()
{
    const int iterations = 500000;

    var methods = new Methods();
    
    Console.Out.WriteLine("Bad Action: " + new Action(() =>
    {
        for(var i = 0; i < iterations; i++)
        {
            try
            {
                methods.DoBad();
            }
            catch(NotImplementedException)
            {
            }
        }
    }).Time());

    Console.Out.WriteLine("Good Action: " + new Action(() =>
    {
        for(var i = 0; i < iterations; i++)
        {
            methods.DoGood();
        }
    }).Time());

    Console.Out.WriteLine("Some Action: " + new Action(() =>
    {
        for(var i = 0; i < iterations; i++)
        {
            methods.DoSomething();
        }
    }).Time());
}

Here are the results:

Bad Action: 00:00:21.3727088
Good Action: 00:00:00.0005447
Some Action: 00:00:04.9421599

Creating the object itself takes time. But throwing the exception adds a lot on top of that.

Somebody was wondering if I compared the time between two methods where one calls a stored proc that does nothing, and the other calls a stored proc that throws an exception. I may look into that.