Data Guard is a disaster-protection architecture consisting of a primary Oracle database and one or more standby Oracle databases to which the primary database copies its data. These standby copies can be used in the event that the primary Oracle database fails. Replication Agent supports replication of data from an Oracle database system that uses Data Guard.
Although you can configure Replication Agent to replicate data from either the Data Guard primary database or a Data Guard standby database, Sybase recommends that you configure Replication Agent to read from a Data Guard standby database transaction log. This way, if the primary Data Guard database fails over to the standby Data Guard database, Replication Agent is already connected to a working Oracle database, and replication is not disrupted.
If you configure Replication Agent to read from a Data Guard standby database transaction log, pds_username must have alter database permission.