Flow through TDP - Teradata Director Program

Teradata® Director Program Reference - 17.20

Teradata Director Program
Release Number
June 2022
English (United States)
Last Update
Product Category
Teradata Tools and Utilities

When the application initiates a request, if TDP can accept the request it is received into the TDP address space or virtual machine. Requests will not be accepted if the specified TDP is not started, the TDP RUN command has not been issued, communication is not established with the database, there is a TDP resources shortage (such as virtual storage), or TDP is being shutdown. The TDP DISPLAY TDP command will indicate if the RUN command has not been issued or TDP is shutting down.

Once accepted, any system security or exit processing is honored then a CP or NP is selected to send the request to the database and the request added to that communication queue. When at the top of the queue, it, possibly packed with other requests, is sent to the database and TDP awaits a response on the same CP or NP. Meanwhile TDP process other requests queued for that or other CPs and NPs. The TDP DISPLAY TDP command will indicate if the SECLOGON is enabled or the Security, Logon, or Monitor exits are enabled.

When a response to the request is completely received from the database, any exit processing is performed, and the request is returned to the application and the application is notified. The TDP DISPLAY TDP command will indicate if the Monitor exit is enabled.

While a request is known to TDP, various TDP commands can be used to ascertain its status. A TDP DISPLAY JOB command can be used to list the database session numbers associated with a z/OS job. It will also indicate whether or not each session has a request active in TDP. The TDP DISPLAY SESSIONS command can be used to obtain information about particular database sessions. If the DETAIL operand is specified, more detailed information is presented about the active request, or if none is active, about the last request. For an active request, the first character of the INFO code indicates where in the flow through TDP the request is:
  • 0x if there is no active request
  • 8x if a request has been accepted by TDP
  • Cx if a request is queued for a CP or NP
  • Ax if a response is expected from the database
  • 9x if a response has been received from the database

The total time the session has existed and the elapsed time for the active (or last) request can also be useful. Also significant is a three-part ratio giving the proportion of total session time spent within TDP, within the database, and within the application.

The TDP DISPLAY CP REQUESTS or DISPLAY NP REQUESTS command lists the requests queued for, and the requests sent on, a CP or NP.