"Sort Aggregate" and sorts in Statistics.

From: Dhimant Patel <drp4kri_at_gmail.com>
Date: Wed, 17 Sep 2008 16:48:59 -0400
Message-ID: <f3e51c10809171348w70307119l5544e179ee158632@mail.gmail.com>

Hi All,

Although current issue does not involve query result cache - I was testing result_Cache hint on Oracle 11g Enterprise edition while experienced this. I always thought "SORT AGGREGATE" operation must involve sorts either disk or memory, is that correct? Following explain plan does not show it being the case.

Could someone please explain?

SQL> select min(SAL), max(sal) from emp;

  MIN(SAL) MAX(SAL)
---------- ----------

       800 5000

Execution Plan

---

Plan hash value: 2083865914

---

| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |

---

|   0 | SELECT STATEMENT   |      |     1 |     4 |     3   (0)| 00:00:01 |
*|   1 |  SORT AGGREGATE    |*      |     1 |     4 |            |
|
|   2 |   TABLE ACCESS FULL| EMP  |    14 |    56 |     3   (0)| 00:00:01 |


---------------------------------------------------------------------------

Statistics

---

          1  recursive calls
          0  db block gets
          7  consistent gets
          0  physical reads
          0  redo size
        591  bytes sent via SQL*Net to client
        523  bytes received via SQL*Net from client
          2  SQL*Net roundtrips to/from client
*          0  sorts (memory)
          0  sorts (disk)*
          1  rows processed

-DP.

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Received on Wed Sep 17 2008 - 15:48:59 CDT