In a standard Microsoft Visual Studio 2008 project, there are two build configurations: debug and release.
The debug build configuration is used for testing and debugging because it includes symbols that the debugger uses to trace the module. Debug builds usually exclude optimizations for speed and size, so you should not use them in a production environment unless you perform testing.
The release build configuration does not include the debugging symbols and is optimized for speed and size. When you have thoroughly tested the debug build of an extension, you should install the release build and then test it again. Occasionally, problems can be present in the release build that are not present in the debug build, so you should never assume that the release build functions correctly without testing. You can debug a release build, but this can be done only at the assembly code level and requires advanced programming skills.
To set the debug or release build configuration for a project, in Visual Studio, select Build, and then click Configuration Manager. A window similar to the following window appears.
In the Project Contexts list, click the project for which the configuration is being set, and change the Configuration column to the desired configuration. Alternatively, use the Active Solution Configuration list to change the configuration for all projects in the solution.