In your database, the snapshot interval is set to 10 minutes for the Automatic Workload Repository
(AWR). The database instance is running for the past 30 days.
View the Exhibit to examine the Automatic Database Diagnostic Monitor (ADDM) task.
The ADDM task is performed every 10 minutes, except the last task. What could be the reason for this?
The snapshot retention period for the AWR was increased before the last task.
The STATISTICS_LEVEL initialization parameter was changed to BASIC and reset to TYPICAL
before the last task.
The optimizer statistics was collected manually by using the DBMS_STATS package before the
The optimizer statistics for few objects in the database were locked before the last task.