Deploying .PDB files in IIS. Any benefit?

Question

I am deploying ASP.NET and Web Service solutions to IIS for a development server. It looks like the last person that did this job deployed all the .pdb file

Answer 1

deploying .pdb files is helpful if you wish to remotely debug your application.

there is an MSDN article here explaining the process

Answer 2

If you are logging exceptions, then deploying the PDB files ensures that the exceptions include line numbers (so Steven A. Lowe has informed me on many occasions ;) )

Answer 3

I always figured the .pdb files were only used by the debugger. If the runtime always checks for them for debug info, that should mean slower execution when throwing an exception, because it has to read the .pdb, right?

So I made a quick test:

using System;
using System.Text;

namespace PdbSpeedTest
{
    class Program
    {
        static void Main(string[] args)
        {
            DateTime start = DateTime.Now;
            try
            {
                Program p = new Program();
                p.Looper(0);
            }
            catch (NotImplementedException e)
            {
                Console.WriteLine(e.StackTrace);
            }
            TimeSpan span = DateTime.Now - start;
            Console.WriteLine(span.TotalMilliseconds.ToString());
        }

        internal void Looper(int x)
        {
            try
            {
                if (x < 100)
                    Looper(x + 1);
                else
                    throw new NotImplementedException("blah!");
            }
            catch (NotImplementedException e)
            {
                throw new NotImplementedException("blah!", e);
            }
        }
    }
}

This just recurses 100 levels deep and throws an exception. Now for the runtime results:

Running as a debug build with the .pdb in the same folder:

C:\Work\PdbSpeedTest\bin\Debug>PdbSpeedTest.exe
   at PdbSpeedTest.Program.Looper(Int32 x) in C:\Work\PdbSpeedTest\Program.cs:line 37
   at PdbSpeedTest.Program.Main(String[] args) in C:\Work\PdbSpeedTest\Program.cs:line 16
31.2504

Running as a debug build without the .pdb:

C:\Work\PdbSpeedTest\bin\Debug>PdbSpeedTest.exe
   at PdbSpeedTest.Program.Looper(Int32 x)
   at PdbSpeedTest.Program.Main(String[] args)
15.6252

Running as a release build with the .pdb:

C:\Work\PdbSpeedTest\bin\Release>PdbSpeedTest.exe
   at PdbSpeedTest.Program.Looper(Int32 x) in C:\Work\PdbSpeedTest\Program.cs:line 37
   at PdbSpeedTest.Program.Main(String[] args) in C:\Work\PdbSpeedTest\Program.cs:line 16
31.2504

Running as a release build without the .pdb:

C:\Work\PdbSpeedTest\bin\Release>PdbSpeedTest.exe
   at PdbSpeedTest.Program.Looper(Int32 x)
   at PdbSpeedTest.Program.Main(String[] args)
15.6252

These were run from a regular old command prompt, not inside Visual Studio. So the .pdb definitely does add stack trace info, and slows down the exception handling. Very interesting!