Hi Duy,
- Functionality to debug/validate the root cause for error in the test run at the application source code level is provided by another HP product - Diagnostics which can be integrated with LoadRunner. You can find additional information in the following link http://www8.hp.com/us/en/software-solutions/software.html?compURI=1175730#.U0KkWXft7Sg
2. Can you please explain in more details question number 2?
3. There is flexibility and it is also important what exactly you are trying to achieve.
For example you are able to simulate different users by parameterizing the log in credentials.
You can record different scripts for the different type of users. Then you can include and run them in one scenario in the Controller.
If there are common parts of the business processes, performed by the different user types you can give them the same transaction name. In this way you will gather aggregated information for this transactions in Analysis.
In Analysis you can use different filters depending on the graph you are using to extract the information you need. For example in Average Transaction Response time graph you can use filter such as: script name, group name, vuser ID, etc.
Additional information about LoadRunner functionality is available in the LoadRunner Tutorial and LoadRunner User guides for the version of LoadRunner you are using.
Kind regards,