Technical Prerequisites

Prerequisites for using the Replication Agent for Oracle with XStream APIs.

The Replication Agent primary database user pds_username must have the XStream administrator privilege to:
- Create or drop an XStream outbound server
- Receive or send data changes from an XStream outbound server
- Capture, synchronize, and apply data changes to an inbound server
To grant the XStream administrator privilege to the pds_username, issue:
```
BEGIN 
DBMS_XSTREAM_AUTH.GRANT_ADMIN_PRIVILEGE( grantee => 'pds_username'); 
END;
/
```
See the Oracle documentation for the DBS_XSTREAM_AUTH package information.
When you use XStream APIs to capture data changes, grant read/write access to the primary database archive logs to enable a non-Oracle Recovery Manager (RMAN) archive truncation method.

If you are using Oracle RMAN for archive truncation, or if the archive truncation method is disabled, read/write access to the archive logs is not required.

Depending on the configuration, Replication Agent may also access archived transactions logs (default) or may process only online transaction logs. For information about redo log and archive log files, see the Replication Agent Primary Database Guide.
Before creating a Replication Agent instance, if the primary TNS service name is different from the pds_database_name, set the pds_service_name to the Oracle Transparent Network Substrate (TNS) service name found in the $ORACLE_HOME/network/admin/tnsnames.ora file.
For example, if tnsnames.ora contains these values:
```
ORCL112 =
  (DESCRIPTION =
    (ADDRESS = (PROTOCOL = TCP)(HOST = huyharry)(PORT = 1521))
    (CONNECT_DATA =
      (SERVER = DEDICATED)
      (SERVICE_NAME = orcl112.sybase.com)
    )
```
Set the pds_service_name to orcl112.sybase.com instead of orcl112 in the resource file.
When you use XStream APIs to read from the transaction log, Replication Agent sets the Oracle Call Interface (OCI) server connection to Dedicated mode by default. If you change the OCI connection mode to Shared, the ORA-26908 exception occurs. For mode descriptions and error exception details, see the Oracle documentation.
When the Oracle Database Vault parameter is enabled at the primary database, you must grant the required privileges to the pds_username using the Oracle user login with the DV_OWNER role. Otherwise, you cannot execute the pdb_xlog init command to create, view, or remove the Replication Agent system objects.
To grant the required permissions to the pds_username:
1. Check whether Oracle Database Vault is enabled at the primary database by issuing:
```
SELECT * FROM V$OPTION WHERE PARAMETER = 'Oracle Database Vault';
```
  A returned result of true indicates that the Oracle Database Vault is enabled, continue with next steps.
  If the result is false, ignore remaining steps.
2. Execute ra_admin prepare to generate a SQL script called prepare_pdb_with_vault_for_replication_init.sql in the <instance_directory>/scripts/prepare, where instance_directory is the Replication Agent installation directory.
3. Run the prepare_pdb_with_vault_for_replication_init.sql script to grant the required privileges.
For more information about Oracle Database Vault, see the Oracle documentation.