19c Active DataGuard DML Redirection
ACTIVE DATAGUARD DML REDIRECTION is a new feature in Oracle 19c which enables the Data Manipulation Language (DML) operations on the Standby Server to be redirected and run on the production (Primary) database.
The updated data will be streamed back to standby to maintain redundancy.
Whenever DML we fire on standby database that operations actually executing on Primary. It might be impacted database performance so we need to avoid too many DML operation execution on standby.
Steps to Understand DML Redirection on Standby Database, Listed below
- Once DML executes on an open standby database.
- DML automatically redirects to the primary DB.
- The DML is executed on the primary DB.
- Then updated data is streamed back to the standby DB.
- Now data is available for the client.
Oracle 19c Active DataGuard DML Redirection
We have two methods to configure DML Redirection with the help of ADG_REDIRECT_DML.
- SESSION LEVEL
How to Enable DML Redirection
Using the below commands you can enable DML Redirection in Oracle 19c Active Data Guard.
Enable SYSTEM LEVEL DML Redirection
SQL> alter system set ADG_REDIRECT_DML=TRUE scope=both;
Enable SESSION LEVEL DML Redirection
SQL>alter session enable adg_redirect_dml;
Note:- You must be remembered, the session-level redirection overwrites the system-level redirection.