Error while executing tuning task in 10gr2

Question

10.2.0.5 on RHEL/5.
select name, status
from dba_sql_profiles
where status = 'ENABLED'
/ 2 3 4
no rows selected
SELECT task_name, EXECUTION_START,EXECUTION_END,status,ERROR_MESSAGE FROM dba_advisor_log WHERE task_name = '1nqbz1wytzjps_tuning_task';
TASK_NAME EXECUTION EXECUTION STATUS ERROR_MESS
1nqbz1wytzjps_tuning_task 24-JAN-13 24-JAN-13 COMPLETED
EXEC DBMS_SQLTUNE.execute_tuning_task(task_name => '1nqbz1wytzjps_tuning_task');
ERROR at line 1:
ORA-13630: The task 1nqbz1wytzjps_tuning_task contains execution results and cannot be executed.
ORA-06512: at "SYS.PRVT_ADVISOR", line 1709
ORA-06512: at "SYS.DBMS_ADVISOR", line 186
ORA-06512: at "SYS.DBMS_SQLTUNE", line 1019
ORA-06512: at line 1
Elapsed: 00:00:00.02
1) I have already executed tuning task on Jan/24 and I'm getting above error while re-executing. What is the correct way to re-execute a tuning task ?
2) How to find whether a sql_profile is stale and how to re-profile it?
3) I understood that, sql profiles are stored in dictionary cache, If we flush shared pool, what happens to the sql profiles?
4) Automatic sql advisor suggest that to consider accepting sql profile. Before going to accept sql profile, How to keep sql_profile up-to-date? fyi..
1- SQL Profile Finding (see explain plans section below)
A potentially better execution plan was found for this statement.
Recommendation (estimated benefit: 99.65%)
- Consider accepting the recommended SQL profile.
execute dbms_sqltune.accept_sql_profile(task_name =>'1nqbz1wytzjps_tuning_task', replace => TRUE);
Thanks !

Answer 1

Error:     ORA-13630 (ORA-13630)
Text:     The task %s contains execution results and cannot be executed.
Cause:The user attempted to execute a task that already contains
     execution results.
Action:Reset the task to its initial state and retry the operation.