audsys.aud$unified column explanation

Querying unified_audit_trail is a pain especially in 12c database due to performance. However, querying this internal audit table audsys.aud$unified, the performance is much faster, and a huge difference in performance. But I have difficulties to find out the object_name associated with actual database objects such as tables, indexes, etc.

For example, I am getting back the obj_name column as following:

CMP4$1372038

CMP1$909656

CMP4$1763197

CMP1$218930

But how could I associate the CMP<n>$<nnnnn> object name to an actual database object names.

Also I am getting the ACTION column as a code such as:

12

1

I have hard time to find out oracle documentation as to what's the corresponding database actions are.