JLOCI test - Oracle logical IO

drop table cpu_test_dummy;
REM create the test table
create table cpu_test_dummy (n primary key) organization index
 tablespace users
  as select rownum n from dba_tab_columns where rownum <= 20000;

sys@CORE4> sys@CORE4> alter session set "_old_connect_by_enabled" = true;
REM See how many seconds the following script runs (elapse time)
set timing on
select count(*)
   from (
     select n
     from cpu_test_dummy
     connect by n > prior n
     start with n = 1 )
   where rownum < 20000;
drop table cpu_test_dummy;


CORE4:

  COUNT(*)
----------
     19999

Elapsed: 00:00:20.57

Execution Plan
----------------------------------------------------------
Plan hash value: 1946589275

-------------------------------------------------------------------------------------------
| Id  | Operation             | Name              | Rows  | Bytes | Cost (%CPU)| Time     |
-------------------------------------------------------------------------------------------
|   0 | SELECT STATEMENT      |                   |     1 |       |     9   (0)| 00:00:01 |
|   1 |  SORT AGGREGATE       |                   |     1 |       |            |          |
|*  2 |   COUNT STOPKEY       |                   |       |       |            |          |
|   3 |    VIEW               |                   |  1000 |       |     9   (0)| 00:00:01 |
|   4 |     CONNECT BY        |                   |       |       |            |          |
|*  5 |      INDEX UNIQUE SCAN| SYS_IOT_TOP_11559 |     1 |    13 |     1   (0)| 00:00:01 |
|   6 |      INDEX FULL SCAN  | SYS_IOT_TOP_11559 |  1000 | 13000 |     2   (0)| 00:00:01 |
|*  7 |      INDEX RANGE SCAN | SYS_IOT_TOP_11559 |  1000 | 13000 |     2   (0)| 00:00:01 |
-------------------------------------------------------------------------------------------

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

   2 - filter(ROWNUM<20000)
   5 - access("N"=1)
   7 - access("N">PRIOR "N")

Note
-----
   - dynamic sampling used for this statement


Statistics
----------------------------------------------------------
         28  recursive calls
          0  db block gets
      20059  consistent gets
         24  physical reads
          0  redo size
        517  bytes sent via SQL*Net to client
        488  bytes received via SQL*Net from client
          2  SQL*Net roundtrips to/from client
          0  sorts (memory)
          0  sorts (disk)
          1  rows processed


RAC4 (itrac415)

  COUNT(*)
----------
     19999

Elapsed: 00:01:00.54

Execution Plan
----------------------------------------------------------
Plan hash value: 3848030415

-------------------------------------------------------------------------------------------
| Id  | Operation             | Name              | Rows  | Bytes | Cost (%CPU)| Time     |
-------------------------------------------------------------------------------------------
|   0 | SELECT STATEMENT      |                   |     1 |       |     9   (0)| 00:00:01 |
|   1 |  SORT AGGREGATE       |                   |     1 |       |            |          |
|*  2 |   COUNT STOPKEY       |                   |       |       |            |          |
|   3 |    VIEW               |                   |  1000 |       |     9   (0)| 00:00:01 |
|   4 |     CONNECT BY        |                   |       |       |            |          |
|*  5 |      INDEX UNIQUE SCAN| SYS_IOT_TOP_53467 |     1 |    13 |     1   (0)| 00:00:01 |
|   6 |      INDEX FULL SCAN  | SYS_IOT_TOP_53467 |  1000 | 13000 |     2   (0)| 00:00:01 |
|*  7 |      INDEX RANGE SCAN | SYS_IOT_TOP_53467 |  1000 | 13000 |     2   (0)| 00:00:01 |
-------------------------------------------------------------------------------------------

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

   2 - filter(ROWNUM<20000)
   5 - access("N"=1)
   7 - access("N">PRIOR "N")

Note
-----
   - dynamic sampling used for this statement


Statistics
----------------------------------------------------------
         28  recursive calls
          0  db block gets
      20059  consistent gets
         24  physical reads
          0  redo size
        413  bytes sent via SQL*Net to client
        396  bytes received via SQL*Net from client
          2  SQL*Net roundtrips to/from client
          0  sorts (memory)
          0  sorts (disk)
          1  rows processed