Most Important New Features to Oracle Data Guard in 11g Release 1(11.1)

July 23, 2009
Oracle, Dataguard, New Features
(1.) Compression of redo traffic over the network in a Data Guard configuration
  This feature improves redo transport performance when resolving redo gaps by compressing redo before it is transmitted over the network.
(2.) Simplified Data Guard management interface
  The SQL statements and initialization parameters used to manage a Data Guard configuration have been simplified through the deprecation of redundant SQL clauses and initialization parameters.
(3.) Enhancements around DB_UNIQUE_NAME
  You can now find the DB_UNIQUE_NAME of the primary database from the standby database by querying the new  PRIMARY_DB_UNIQUE_NAME column in the V$DATABASE view. Also, Oracle Data Guard release 11g ensures each database's DB_UNIQUE_NAME is different. After upgrading to 11g, any databases with the same DB_UNIQUE_NAME will not be able to communicate with each other.
(4.) Use of physical standby database for rolling upgrades
  A physical standby database can now take advantage of the rolling upgrade feature provided by a logical standby. Through the use of the new KEEP IDENTITY clause option to the SQL ALTER DATABASE RECOVER TO LOGICAL STANDBY statement, a physical standby database can be temporarily converted into a logical standby database for the rolling upgrade, and then reverted back to the original configuration of a primary database and a physical standby database when the upgrade is done.
(5.) Heterogeneous Data Guard Configuration
  This feature allows a mix of Linux and Windows primary and standby databases in the same Data Guard configuration.
(6.) The ARCH redo transport mode has been deprecated
(7.) Real-time query capability of physical standby
  This feature makes it possible to query a physical standby database while Redo Apply is active.
(8) Snapshot standby
  A snapshot standby database is new type of updatable standby database that provides full data protection for a primary database.