DBA_HIST_SYSTEM_EVENT displays historical information on total waits for an event. This view contains snapshots of V$SYSTEM_EVENT.
| Column | Datatype | NULL | Description | 
|---|---|---|---|
| SNAP_ID | NUMBER | NOT NULL | Unique snapshot ID | 
| DBID | NUMBER | NOT NULL | Database ID for the snapshot | 
| INSTANCE_NUMBER | NUMBER | NOT NULL | Instance number for the snapshot | 
| EVENT_ID | NUMBER | NOT NULL | Identifier of the wait event | 
| EVENT_NAME | VARCHAR2(64) | NOT NULL | Name of the wait event | 
| WAIT_CLASS_ID | NUMBER | Identifier of the Class of the Wait Event | |
| WAIT_CLASS | VARCHAR2(64) | Name of the Class of the Wait Event | |
| TOTAL_WAITS | NUMBER | Total number of waits for the event | |
| TOTAL_TIMEOUTS | NUMBER | Total number of timeouts for the event | |
| TIME_WAITED_MICRO | NUMBER | Total amount of time waited for the event (in microseconds) | |
| TOTAL_WAITS_FG | NUMBER | Total number of waits for the event, from foreground sessions | |
| TOTAL_TIMEOUTS_FG | NUMBER | Total number of timeouts for the event, from foreground sessions | |
| TIME_WAITED_MICRO_FG | NUMBER | Amount of time waited for the event (in microseconds), from foreground sessions |