There is 2 kind of alerts in database :
- Stateful alerts : Alerts based on threshold (Physical reads Per sec, User commits Per sec)
- Stateless alerts : Alerts that does not depends on any kind of threshold (Snapshot too old, Recovery are low free space)
Stateless alerts
Stateless alerts are logged in the DBA_ALERT_HISTORY table.
Stateful alerts
Stateful alerts are logged in the DBA_OUTSTANDING_ALERTS table.
When the situation is resolved, the alert is cleared from this table and moved automatically to the DBA_ALERT_HISTORY.
Action on alerts
An alert could be cleared from the history. Its status changes to cleared and is keeped in the table.
An alert could be purged from the alert log history. In this way, the alert is removed from the repository and discared.
