V$ARCHIVE_GAP displays information about archive gaps on a standby database. This view can be used to find out the current archive gap that is blocking recovery.
| Column | Datatype | Description | 
|---|---|---|
| THREAD# | NUMBER | Thread number of the missing archived redo log files. The number is 1 for a single instance. For Real Application Clusters, this column will contain different numbers. | 
| LOW_SEQUENCE# | NUMBER | Lowest sequence number of the log files received on the standby system | 
| HIGH_SEQUENCE# | NUMBER | Highest sequence number of the log files received on the standby system |