How do I debug random crashes in my web app in IE?

Question

Here's a classic "works on my machine, but not in production" scenario.

ASP.NET app written in C#. Simple UI with some items to select. Once the user clicks "Go", it runs to the server and builds a PDF file with some data-driven graphics in it (housed in SQL Server) and sends the PDF back to the user for use.

I think it's a webserver issue myself because a couple months ago, everything seemed to be working fine. But the host keeps changing things in their infrastructure. Now IE just randomly times out and the number of graphics that the PDF can house is significantly less before the IE timeout. Nothing in the code has changed and the DB timeout in the config is the same.

How can I debug this scenario?

Answer 1

Where is the "crash" happening? is your Web Server, App Server, DB Server dying? Or is IE just failing to return a result?

If IE is failing... which version/windows service pack? (e.g. IE6 on WinXP SP1 isn't the best setup)

If it is IE (and you can test the same setup) use Fiddler to check exactly what is being sent/received over HTTP.

If the App/Web/DB is failing... can you post some log info?

Answer 2

If you are getting HTTP Error 500 Internal server error Check the web server log. If browsers are crashing check with fiddler in case of IE or Firebug with FF.