Step by Step Guide on How to Create Logical Standby [ID 738643.1]

Goal

Step by Step Guide on How to Create Logical Standby

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Solution

Prerequisite

1 : Before setting up a logical standby database, ensure the logical standby database can maintain the data types and tables in your primary database. See Appendix C of the dataguard documentation for a complete list of data type and storage type considerations.

2 : Ensure Table Rows in the Primary Database Can Be Uniquely Identified.

2.1 : Find Tables Without Unique Logical Identifier in the Primary Database.

Use following query to display a list of tables that SQL Apply may not be able to uniquely identify:
2.2 : If your application ensures the rows in a table are unique, you can create a disabled primary key RELY constraint on the table. Use ALTER TABLE command to add a disabled primary-key RELY constraint.
The following example creates a disabled RELY constraint on a table named mytab, for which rows can be uniquely identified using the id and name columns:

Creating a Logical Standby Database:

Step 1 Create a Physical Standby Database Create a Physical Standby Database and make sure that there is no error in remote archiving to Standby from Primary Database.

Please refer following documentations for creating physical standby database:

For 10.2:
Oracle® Data Guard Concepts and Administration 10g Release 2 (10.2)

For 11.1:
Oracle® Data Guard Concepts and Administration 11g Release 1 (11.1)

Step 2 Make Sure that Physical Standby is in Sync with Primary Database
Use following query on Standby to check:

There should not be any difference in Last Seq Received and Last Seq Applied on Physical Standby.

Step 3 Stop Redo Apply on the Physical Standby Database
Step 4 Set Parameters for Logical Standby in Primary

4.1. Change VALID_FOR in LOG_ARCHIVE_DEST_1 on Primary to (ONLINE_LOGFILES,ALL_ROLES)
4.2. Set LOG_ARCHIVE_DEST_3 for logs which will received on Standby from Primary
Note: LOG_ARCHIVE_DEST_3 only takes effect when the primary database is transitioned to the logical standby role.

Step 5 Build a Dictionary in the Redo Data on Primary Database
The DBMS_LOGSTDBY.BUILD procedure waits for all existing transactions to complete. Long-running transactions executed on the primary database will affect the timeliness of this command.

Step 6 Convert to a Logical Standby Database
For db_name, specify a database name to identify the new logical standby database. If you are using a spfile for standby, then command will update the db_name parameter otherwise it will issues a message reminding you to set the name of the DB_NAME parameter after shutting down the database.

Step 7 Create a New Password File for Logical Standby Database
This step is required in 10.2 only and should not be performed in 11g.

Step 8 Shutdown and Startup Logical Standby Database in Mount Stage
Step 9 Adjust Initialization Parameter on Logical Standby Database
Step 10 Open the Logical Standby Database
Step 11 Start Logical Apply on Standby