DECLARE
   t1_start   PLS_INTEGER;
   t1_end     PLS_INTEGER;
   t2_start   PLS_INTEGER;
   t2_end     PLS_INTEGER;
   x          PLS_INTEGER;
BEGIN
   -- I know that 100 is a valid OBJECT_ID in my db

   t1_start := DBMS_UTILITY.get_time;
   -- this will use index
   for i in 1..1000 loop
     select count(*) into x from all_objects_tmp_copy where object_id = 100;
   end loop;
   t1_end := DBMS_UTILITY.get_time;
   DBMS_OUTPUT.put_line ('Hundredths of a sec to do 1000 * test1 (indexed query) :'|| TO_CHAR (t1_end - t1_start));
   
   t2_start := DBMS_UTILITY.get_time;
   -- this will use NOT use index
   for i in 1..1 loop
     select count(*) into x from all_objects_tmp_copy where object_id+0 = 100;
   end loop;
   t2_end := DBMS_UTILITY.get_time;
   DBMS_OUTPUT.put_line ('Hundredths of a sec to do 1 * test2 (NOT indexed query) :' || TO_CHAR (t2_end - t2_start));
END;
/