Today when doing some research on “FAST DUAL”, I came across following error when I try to set autotrace on:

SQL> set autotrace on
SP2-0618: Cannot find the Session Identifier. Check PLUSTRACE role is enabled
SP2-0611: Error enabling STATISTICS report
SQL>

Anyway I ignored the error and ran my sql.

The result was I could see the execution plan but not statistics as follows.

SQL> select sysdate from dual;

SYSDATE
———
17-DEC-07

Execution Plan
———————————————————-
Plan hash value: 1388734953

—————————————————————–
| Id | Operation | Name | Rows | Cost (%CPU)| Time |
—————————————————————–
| 0 | SELECT STATEMENT | | 1 | 2 (0)| 00:00:01 |
| 1 | FAST DUAL | | 1 | 2 (0)| 00:00:01 |
—————————————————————–

SQL>

I research about it and found out that my user don’t have PLUSTRACE role assign and I just need to assign the role to correct the error.

But when I tried to grant the role, I got another error as follows:

SQL> grant plustrace to scott;
grant plustrace to scott
*
ERROR at line 1:
ORA-01919: role ‘PLUSTRACE’ does not exist

After that I create the PLUSTRACE role by running the plustrce.sql at $ORACLE_HOME/sqlplus/admin as follows:

SQL> @’D:\oracle\product\11.1.0\db_1\sqlplus\admin\plustrce.sql’;
SQL>
SQL> drop role plustrace;
drop role plustrace
*
ERROR at line 1:
ORA-01919: role ‘PLUSTRACE’ does not exist

SQL> create role plustrace;

Role created.

SQL>
SQL> grant select on v_$sesstat to plustrace;

Grant succeeded.

SQL> grant select on v_$statname to plustrace;

Grant succeeded.

SQL> grant select on v_$mystat to plustrace;

Grant succeeded.

SQL> grant plustrace to dba with admin option;

Grant succeeded.

SQL>
SQL> set echo off
SQL>

Then granted the PLUSTRACE role.

SQL> grant plustrace to scott;

Grant succeeded.

SQL>

After granting I closed my old sqlplus window and open the new window and login as scott user.

when I ran my sql, the result was as expected that is explain plan with statistics as follows:

SQL> set autotrace on
SQL> select sysdate from dual;

SYSDATE
———
17-DEC-07

Execution Plan
———————————————————-
Plan hash value: 1388734953

—————————————————————–
| Id | Operation | Name | Rows | Cost (%CPU)| Time |
—————————————————————–
| 0 | SELECT STATEMENT | | 1 | 2 (0)| 00:00:01 |
| 1 | FAST DUAL | | 1 | 2 (0)| 00:00:01 |
—————————————————————–

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

SQL>

So had good end to a day!