Hi All,
(DB 11.2.0.3- OS Solaris)
Yesterday our database crashed due to a ora-494 incident. After restarting the db and starting OEM I found that nothing showing in OEM performance page. So I googled for this issue and found that the behind ASH view is not populating:
select * from V$ACTIVE_SESSION_HISTORY where sample_time >= trunc(sysdate)
returns no records while executing the statement with no WHERE clause will show some rows for yesterday before crash and before-ward. I found that the mechanism of enabling/disabling of ASH gathering is based on the parameter CONTROL_MANAGEMENT_PACK_ACCESS. here is its value:
SQL> sho parameter CONTROL_MANAGEMENT_PACK_ACCESS;
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
control_management_pack_access string DIAGNOSTIC+TUNING
please help me on why this view ASH gathering is stopped and how can I restart it.
Regards