OCI-31485
invalid database link
Cause
The database link used to connect from a staging database to a source database was invalid. The database link may not exist, may not be accessible to the current user, or may have been redefined since the distributed HotLog change source was created.
Action
Ensure that there is a database link to the source database for the distributed HotLog change source. Also, ensure that this database link is accessible to the current user.