如何通过kerberised身份验证在Oracle数据库链接中代理到另一个数据库用户

背景：

2个数据库主机（带用户）：DB1（UserA）、DB2（UserA、UserB）

来自DB1，UserA的数据库链接已创建，并可与以下SQL配合使用

CREATE DATABASE LINK "DB_LINK"
   USING '(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = <DB2'S HOSTNAME>)(PORT = <PORT#>))
(CONNECT_DATA =
(SERVER = DEDICATED)
(SERVICE_NAME = <DB2'S NAME>)
)
)';

CREATE DATABASE LINK "DB_LINK"
   CONNECT TO UserB IDENTIFIED by <pw>
   USING '(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = <DB2'S HOSTNAME>)(PORT = <PORT#>))
(CONNECT_DATA =
(SERVER = DEDICATED)
(SERVICE_NAME = <DB2'S NAME>)
)
)';

CREATE DATABASE LINK "DB_LINK"
   CONNECT TO UserA[UserB] IDENTIFIED by <UserA's pw>
   USING '(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = <DB2'S HOSTNAME>)(PORT = <PORT#>))
(CONNECT_DATA =
(SERVER = DEDICATED)
(SERVICE_NAME = <DB2'S NAME>)
)
)';

ALTER USER UserB GRANT CONNECT THROUGH UserA;