Debug System in Joomla give a lot of information, especially to the developer. The way we enable it is from the global configuration. 

In recent time I started wondering why my debug information like profiling, language translation,queries are not displaying even if all the configuration like system-debug plugin enabled with all the basic as well as language options marked "yes".

After a lot of googling around I found that if the system-cache plug-in is enabled then the debug information will not work.

Never read this anywhere.Thought this could help someone.