I have used the exhaustive knowledge that the database holds about its own structure in many ways

during my ten years with Oracle Consulting. Sometimes when you venture the structures of the dictionary chance does lead you into a nice discovery. As in this case when I found that you can draw a sort of map of an application very quickly querying v$segment_statistics. These map will point out deficiencies in the physical design rather quickly. Once they are resolved, the question of the optimal buffer cache size arises and will be answered.