Leveraging Logical Standby Databases in Oracle 11g Data Guard
Jim Czuprynski, jczuprynski@zerodefectcomputing.com

A logical standby database offers some interesting alternatives for offloading a reporting workload, protection against physical block corruption, patching, and even disaster recovery purposes.

Unlike a physical standby database, a logical standby's physical structure may be different (e.g. different tablespaces or datafiles). Change data may be selectively applied to particular tables and indexes, making it possible for a logical standby database to offer data from a combination of sources.

A logical standby database will capture change data for all supported datatypes, allowing you to build materialized views, materialized view logs, and even additional indexes on existing production tables that would be prohibitively expensive to maintain against the same tables on the primary database.

Alogical standby database's datafiles aren't an exact physical copy of the primary database's datafiles. Therefore, it offers protection against physical block corruption on the primary database because redo is applied using SQL Apply methods.