Calculate the CPU cost of a user function based on the elapsed
time of the function.
This CPU cost is used by extensible optimizer routines.
Function: ESTIMATE_CPU_UNITS Function Returns the approximate number of CPU instructions (in thousands) corresponding to a specified time interval (in seconds).
For full documentation of the packaged procedures above see the Oracle Manual:
"Oracle9i Supplied PL/SQL Packages and Types Reference"
or the book Oracle Built in Packages by Steven Feuerstein et al