Sort operation is counted same regardless of the table size

Sort operation is counted same regardless of whether the table is big or small

In the following example, one sort is in memory against a small table, one sort is in disk against a big table, but they both count 1 sort operation.

**********************  Case 1  ***************************

scott@ORCL> select * from emp order by 5;

15 rows selected.


Execution Plan
----------------------------------------------------------
Plan hash value: 301026995

----------------------------------------------------------------------------
 Id   Operation            Name  Rows   Bytes  Cost (%CPU) Time    
----------------------------------------------------------------------------
   0  SELECT STATEMENT              15    540      4  (25) 00:00:01
   1   SORT ORDER BY                15    540      4  (25) 00:00:01
*  2    FILTER                                                     
   3     TABLE ACCESS FULL EMP      15    540      3   (0) 00:00:01
----------------------------------------------------------------------------

Predicate Information (identified by operation id):
---------------------------------------------------

  2 - filter(CASE  WHEN "SAL">=2000 THEN
             SYS_AUDIT('SCOTT','EMP','EMP_SEL',3) ELSE NULL END  IS NULL)


Statistics
----------------------------------------------------------
         4  recursive calls
        15  db block gets
         9  consistent gets
         0  physical reads
       696  redo size
      1356  bytes sent via SQL*Net to client
       381  bytes received via SQL*Net from client
         2  SQL*Net roundtrips to/from client
         1  sorts (memory)
         0  sorts (disk)
        15  rows processed

**********************  Case 2  ***************************

scott@ORCL> select * from big_table order by 5;

1000000 rows selected.


Execution Plan
----------------------------------------------------------
Plan hash value: 1472477105

----------------------------------------------------------------------------------------
 Id   Operation           Name       Rows   Bytes TempSpc Cost (%CPU) Time    
----------------------------------------------------------------------------------------
   0  SELECT STATEMENT                 998K    98M        24421   (1) 00:12:03
   1   SORT ORDER BY                   998K    98M   260M 24421   (1) 00:12:03
   2    TABLE ACCESS FULL BIG_TABLE    998K    98M         3383   (2) 00:01:41
----------------------------------------------------------------------------------------


Statistics
----------------------------------------------------------
       117  recursive calls
        43  db block gets
     14457  consistent gets
     30123  physical reads
       520  redo size
  21149727  bytes sent via SQL*Net to client
    733707  bytes received via SQL*Net from client
     66668  SQL*Net roundtrips to/from client
         0  sorts (memory)
         1  sorts (disk)
   1000000  rows processed