To allow orderly migration to new releases of Teradata software, define a minimum of two TDP instances:
- Production system
- Test system
As new software versions are released, the test system exercises the new software while the production system runs the currently operational production software.
An application selects the TDP with which it communicates either by default, as defined in the System Parameter Block, or by specifying a TDP subsystem through Call-Level Interface (CLI) routines.
The examples assume that the test and production systems use the following TDP identifiers:
- TDP0 (production TDP)
- TDP1 (test TDP)
The following figure shows a Teradata configuration where multiple clients on an IBM System z mainframe computer are attached to one Teradata server using a TDP on each client.
The following figure shows Teradata configuration where multiple clients on an IBM System z mainframe computer are attached to two Teradata servers using a TDP on each client.