External stored procedures cannot do standard I/O or network I/O.
Under the following conditions, external stored procedures can do I/O or otherwise interface with the operating system such that the operating system retains resources such as file handles or object handles.
| IF the CREATE PROCEDURE or REPLACE PROCEDURE statement … | THEN the external stored procedure … |
|---|---|
| specifies the EXTERNAL SECURITY clause | executes as a separate process under the authorization of a specific native operating system user established by a CREATE AUTHORIZATION or REPLACE AUTHORIZATION statement. The external stored procedure can access the system resources for which the user has privileges. The procedure must release opened resources (close handles) before it completes. |
| omits the EXTERNAL SECURITY clause | can do I/O if the external stored procedure runs in protected execution mode. In protected execution mode, the external stored procedure runs as a separate process under 'tdatuser', a local operating system user that the Teradata Database installation process creates. The external stored procedure can access the system resources for which tdatuser has privileges. The procedure must release opened resources (close handles) before it completes. For more information on protected execution mode, see Protected Mode Execution. |