Does ArcGIS support Oracle DML redirection or database links?

Answer

ArcGIS does not support DML redirection, an Oracle Active Data Guard feature, due to underlying user-defined types (UDTs) restrictions with remote databases. See: 2.1.9 Restriction on Using User-Defined Types with a Remote Database. DML redirection uses a database link to connect to a remote database, and when DML queries on user-defined types are sent, the following error is returned: 

ORA-22804 remote operations not permitted on object tables or user-defined type columns

This error is due to the remote database's inability to interpret and implement the local database type. There are further complications to user-defined types (UDTs), including the use of local variables in PL/SQL code and remote procedure calls, which ArcGIS relies heavily upon for versioning operations with the database. 

While there may be some simple database transactions that work, particularly with non-spatial data, much of the ArcGIS enterprise geodatabase functionality is impacted by this known restriction in Oracle's software.