16623, 0000, "database detected role change"
*Cause: A successful switchover or failover operation had been completed
and was detected during database startup or broker health check.
If this database was unavailable during a switchover or failover
operation, it may not be a viable standby database for the new
primary database and was disabled by the Data Guard broker.
*Action: Connect to the new primary database and examine the broker
configuration for databases that were disabled and that may require
reinstatement or re-creation.