The topics that i thought i knew were the ones i was a little weak viz. Consolidation and Mass Processing in the SAP MDG certification exam syllabus. The problem is with the application. Knowing all about theory does not work and hence i got to subscribe the premium membership of the C_MDG_1909 mock tests which is full of such questions that helped me get an edge in my preparation for the very elaborate and beneficial exam for me. I scored 81% and am very happy.