Oracle 19c New feature - Active Data Guard DML Redirection

DML operations on a standby can be transparently redirected to and run on the primary database. This includes DML statements that are part of PL/SQL blocks.

To configure automatic redirection of DML operations for all standby sessions in an Active Data Guard environment:

  ADG_REDIRECT_DML=TRUE 

The Active Data Guard session waits until the corresponding changes are shipped to and applied to the Active Data Guard standby. Read consistency is maintained during the DML operation and the standby database on which the DML is run can view its uncommitted changes.

However, all the other standby database instances can view these changes only after the transaction is committed.

To configure automatic redirection of DML operations for the current session, use the following command:

  SQL>ALTER SESSION ENABLE ADG_REDIRECT_DML; 

SQL>show parameter redirect

 NAME                                 TYPE        VALUE
 ------------------------------------ ----------- -------  
 adg_redirect_dml                     boolean     TRUE