Why is the WCF data service working better while Fiddler is running?

Question

I have a Windows application that connects to a WCF data service hosted on the same machine.

The first thing that happens when the application starts is a query that returns from 0 to 3 results. Here is the code:

var environments = ctx.Environments .AddQueryOption("$filter", "Environment eq '" + ConfigurationManager.AppSettings["environment"] + "'") .AddQueryOption("$expand", "Departments, SecurityGroups"); 

The next thing I do is check if (environment.Count () == 0), which takes about 10 seconds to evaluate. This seems to be the slowest for the first time, but always takes more than 6 seconds. However, if I run Fiddler, I always get the results right away.

Why is Fiddler launching accelerated?

Answer 1

I appreciate all the answers, but in the end, something was wrong with my VS 2010 development environment. I was able to handle the slow first answer by supporting Fiddler and working, but after installing the Telerik control set, my applications took almost a minute to load the form during debugging. Suspecting that this was due to another problem, I installed VS 2012 and updated my projects, and now everything works as expected.

Thanks again for your answers.

Answer 2

When you run fiddler, it acts as a proxy for all network calls, right? This proxy probably responds faster than the real DNS host. What time did you establish the connection setup in the bind configuration?

Answer 3

As weismat suggests, these could be DNS issues. If you are using DNS names in the WCF URL, try using loopback ip (127.0.0.1) or the local IP address instead.