15.00 - Protected Mode External Procedure Servers - Teradata Database

Teradata Database SQL Data Definition Language Detailed Topics

prodname
Teradata Database
vrm_release
15.00
category
Programming Reference
featnum
B035-1184-015K

Protected Mode External Procedure Servers

Protected mode external procedures, including secure mode procedures, run under a separate process from the Teradata Database. External procedures set up to require external security run in a subtype of protected mode called secure mode. The system sets up separate processes, or servers, to support secure mode procedures (see SQL External Routine Programming for details).

The following series of events occurs the first time a secure mode external procedure is invoked in a session. The process is essentially identical for protected mode external procedures.

1 The external procedure secure server setup logic looks at the authorization and determines whether a secure server process is already set up for the given OS user authorization.

Because this is the first time the procedure has been invoked in the session, no secure server process has been set up.

2 The authorization is not set up, so the process validates the OS user by making a validation check on the user name and password.

If the logon attempt using the provided authorization information fails, the system returns an error to the session.

3 If the authorization is successful, the system creates the secure server process and the procedure executes.

If this is not the first time the procedure has been executed for the session, the following series of events occurs:

1 The external procedure secure server setup logic reads the authorization and determines that there is already a secure server process set up with that authorization.

2 The procedure is executed using the existing secure server.

If the maximum number of secure servers has been created and a new request comes in for a given authorization for which there is no established secure server, the following series of events occurs:

1 The external procedure secure server logic attempts to find a secure server with the given authorization. It does not find one and determines that the maximum number of secures servers has already been set up.

2 The authorization is not set up, so the process validates the OS user by making a validation check on the user name and password.

If the logon attempt using the provided authorization information fails, the system returns an error to the session.

3 The external procedure secure server logic finds the least used secure server process and terminates it.

4 The new secure server process is created and the procedure is executed.