ASP.NET Website DLL: Debug vs. Release version

Question

Hello,

When uploading my ASP.NET web application .dll file to my website's /bin/ directory, are there any disadvantages to using the debug version as opposed to recompiling a release build.

For example, while working locally on the website, the build configuration is set to Debug. When things look good, I go ahead and upload the latest .dll for the website/webapp. Should I instead at that point switch the build configuration to Release, then compile, and then upload that version of the .dll to the server?

I hoping this question isn't a duplicate. I read a number of other questions with similar words in the subject, but didn't find something directly related to my question.

Thanks,

Adam

Answer 1

http://weblogs.asp.net/scottgu/archive/2006/04/11/Don_1920_t-run-production-ASP.NET-Applications-with-debug_3D001D20_true_1D20_-enabled.aspx

Answer 2

A lot of it depends on what your individual needs are. In general people frown on putting the debug build into production for performance reasons. The emitted debug code is apparently not optimized and contains debug symbols that can slow down the execution of the code.

On the other hand, I've worked places where the policy was to put debug builds in production because it makes it easy to see line number, etc, when the code throws exceptions. I'm not saying I agree with this position, but I've seen people do it.

Scott Hanselman has a good post on doing a hybrid version of Debug and Release that could get you the best of both worlds here.

Answer 3

Running with debug assemblies is a little heavier on performance, as they take up more memory, but usually not extremely so. You should only deploy a release build when it's really a "release". If you still anticipate some level of unexpected behavior in the wild, I'd consider using debug assemblies, so you will get more useful information from unhandled exceptions. The real performance "gotcha" is having debug="true" in your web.config.

Answer 4

Very few applications are going to see a significant difference in performance between release and debug builds. If you're running a small to medium sized application and you think there might be any bugs you haven't caught, use the debug build.

Answer 5

If you have a low volume website, you will never see the performance penalty of a Debug assembly in any measurable way. If you have high volume, look into other means of logging/instrumenting code instead.

On a high-volume website, you DO need to perform extensive stress and load testing to try very hard to break the application before it goes into production. I would do the first pass of that testing with Debug assemblies (since you probably WILL break stuff, and it will make it easier to see where). Then, repeat with the Release assemblies to make sure they behave the same way as the Debug ones.