rajendra_thanekar

 Profile Answers by rajendra_thanekar 

• Mar 14th, 2008

 

A standby database is a transactionally consistent copy of the primary database. Using a backup copy of the primary database, you can create up to nine standby databases.

A standby database can be either a physical standby database or a logical standby database.


A Physical standby database provides a physically identical copy of the primary database, with on disk database structures that are identical to the primary database. This standby database is kept synchronized with the primary database by recovering/applying the redo data received from the primary database.

A Logical standby database has same logical information as the production database, although the physical organization and structure of the data can be different. The logical standby database is kept synchronized with the primary database by transforming the data in the redo received from the primary database into SQL statements and then executing the SQL statements on the standby database.