使用DBMS_UTILITY.GET_TIME来捕获某段代码的执行时间

DBMS_UTILITY.GET_TIME常用于计算某段代码间的时间消耗，DBMS_UTILITY.GET_TIME返回值本身并不是指当前的时间，而是一个the number of 100ths of seconds that have elapsed from an arbitrary time.

Usage Notes
You should not use GET_TIME to establish the current time, but only to calculate the elapsed time between two events. Without GET_TIME, Oracle functions can only record and provide elapsed time in second intervals, which is a very coarse granularity in today's world of computing. With GET_TIME, you can get a much finer understanding of the processing times of lines in your program.
Example

DECLARE
 L_START NUMBER;
 L_END NUMBER;
 L_DIFF NUMBER;
BEGIN
 L_START := DBMS_UTILITY.GET_TIME ;
 DBMS_LOCK.SLEEP(10);
 L_END := DBMS_UTILITY.GET_TIME ;
 L_DIFF := (L_END-L_START)/100;
 DBMS_OUTPUT.PUT_LINE('Start: '||to_char(L_START));
 DBMS_OUTPUT.PUT_LINE('End:   '||to_char(L_END));
DBMS_OUTPUT.PUT_LINE('Elapsed Time: '|| l_diff ||' seconds...');
END;
                                 
PL/SQL block, executed in 10.51 sec.
Start: 1719251553                   
End:   1719252554                   
Elapsed Time: 10.01 seconds...      
Total execution time 12.09 sec.