TDP's Role in a Database System - Teradata Director Program

As shown in the following figure, the database supports a variety of clients that can be attached using either a mainframe channel or a network connection. Client applications communicate with the database to load, update, and query data that it holds. This document describes the software interface for mainframe clients.

TDP provides a high-performance communication interface between mainframe applications and the database. One database system is logically subdivided into multiple Logical-hosts, each of which can be connected to one and only one TDP: any mention of the database in TDP documentation implies one of these Logical-hosts, on whatever physical database server it might reside. Every mainframe system connected to the database has at least one TDP associated with it. Therefore, a mainframe connected to more than one system has more than one TDP. The connections and so the TDPs might be on any number of IBM LPARs running MVS. On any MVS, any number of TDPs, each of any release, may be started simultaneously. The operation and resources, of every TDP are completely independent of any others. The TDP executable modules for a release may be shared by any number of TDPs of that same release, except that those TDP modules in the MVS LPA for one release must be differentiated from the same modules for a different release using different one character suffixes.

Each TDP is identified by a tdpid, which is meaningful only within the mainframe system. On z/OS, a tdpid corresponds to a Subsystem id so consists of four characters, the first three of which are 'TDP' and the fourth uniquely differentiates TDPs on that system. Each TDP operates in its own address space.

TDP displays messages and accepts commands from operator consoles, or software that emulates such consoles. Under z/OS, TDP-defined records are written to the System Recording Facility (SMF). When channel devices are used to communicate with the database, standard records are written to LOGREC for problems with the devices used. Under z/OS, internal diagnostics can utilize the Generalized Trace Facility (GTF).