logical standby database

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 An Oracle Logical Standby Database is a type of standby database that provides transaction-level replication and is designed for high availability and disaster recovery purposes. It is a feature of Oracle's Data Guard technology.


In a logical standby database configuration, changes made to the primary database are captured in the form of SQL statements, which are then transformed and applied to the logical standby database. Unlike a physical standby database that replicates data at the block level, a logical standby database replicates data at the SQL level.

Here are some key features and characteristics of an Oracle Logical Standby Database:

  • Read-Write Access
  • Different Database Structures
  • Data Filtering
  • DML and DDL Replication
  • Delayed Apply
  • Switchover and Failover




steps to create logical standby 
  • Prepare the Primary Database:ALTER DATABASE ADD SUPPLEMENTAL LOG DATA;
  • Enable force logging: ALTER DATABASE FORCE LOGGING;
  • Create a Standby Initialization Parameter File:DB_UNIQUE_NAME, LOG_ARCHIVE_CONFIG, and LOG_ARCHIVE_DEST_n
  • Copy the Primary Database Files
  • Create the Standby Control File:ALTER DATABASE CREATE STANDBY CONTROLFILE AS 'path_to_standby_control_file';
  • Start the Standby Database in Nomount Mode:STARTUP NOMOUNT PFILE='path_to_standby_pfile';
  • Configure Log Shipping:
  • Create the Logical Standby Database:CREATE LOGICAL STANDBY DATABASE SQL statement 
  • Start redo Apply : ALTER DATABASE START LOGICAL STANDBY APPLY;
  • Verify the Logical Standby Database:


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