DBA_HIST_EVENT_HISTOGRAM displays event histogram historical statistics information. This view contains snapshots of V$EVENT_HISTOGRAM.
| 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 | |
| WAIT_TIME_MILLI | NUMBER | NOT NULL | Wait time (in milliseconds) | 
| WAIT_COUNT | NUMBER | Wait count |