Oracle Data Guard 11g Handbook

CHAPTER 4Logical Standby

Data Guard logical standby was introduced in Oracle Database 9i Release 2 as part of the Enterprise Edition. The idea behind a logical standby database is simple: mine the primary database redo and reconstruct the higher level “equivalent” SQL operations that resulted in the database changes, and then apply these equivalent SQL statements to maintain a standby database. The benefits are obvious: the standby database can not only be open for reads, but it can also support additional entities such as indexes and materialized views that can be too expensive to maintain at the primary database. In addition, you can add other tables or even entire schemas to a logical standby database and have complete read-write access to ...