Server Generated Alerts

In Oracle 10g, the SGA can be accessed directly and the MMON wakes up every minute to compute the metric values. For those metrics with thresholds, MMON verifies these values and generates alerts as needed. Alerts based on threshold levels can be triggered at warning levels and critical levels. These levels can be internally set, customer defined, or customer altered from preset values.

There are two kinds of server generated alerts, threshold alerts and non-threshold alerts. Most alerts are configured by setting two threshold values on database metrics, a warning threshold and a critical threshold. These threshold alerts are also known as stateful alerts, which are automatically cleared upon fixing the alert condition. Stateful alerts are stored in dba_outstanding_alerts and are moved to dba_alert_history when cleared. Table 4.3 describes the structure of the dba_outstanding_alerts view

COLUMN	DESCRIPTION
SEQUENCE_ID	Sequence number for the Alert
REASON_ID	Alert reason ID
OWNER	Object owner for which the alert was issued
OBJECT_NAME	Object Name
SUBOBJECT_NAME	Sub-object Name
OBJECT_TYPE	Object type
REASON	Alert's Reason
TIME_SUGGESTED	Time of last update for the alert
CREATION_TIME	Time of first creation of the alert
SUGGESTED_ACTION	Recommended action