Installing IMS Interface for Two-Phase Commit Protocol - Teradata Tools and Utilities

Teradata® Tools and Utilities for IBM z/OS Installation Guide - Teradata Director Program - 17.20

Teradata Tools and Utilities
Release Number
September 2022
English (United States)
Last Update
Product Category
Teradata Tools and Utilities
PrerequisiteSubstitute the DBC prefix in place of dbcpfx for all library names.
If your site runs applications with the Two-phase commit protocol using IMS as a coordinator, you must install the IMS Interface using one of the methods already described and then complete the following steps. Two-phase commit is described in Teradata® Director Program Reference, B035-2416.
  1. Make sure the dbcpfx.AUTHLOAD library is authorized by APF.
    The AUTHLOAD library contains the DBCHCPI module, which implements the interface between the IMS coordinator and the Vantage server. The DBCHCPI module has one alias named DBCHCPI0.
  2. Add the AUTHLOAD library to the startup JCL for the control region. In the startup JCL for the control region, you must add a DFSESL statement pointing to dbcpfx.AUTHLOAD. The following is a sample control region DFSESL statement:
  3. Define the AUTHLOAD library in the dependent regions.
    For each dependent region that uses the IMS Interface with Two-phase commit processing, add a DFSESL statement to the IMSMSG JCL to define dbcpfx.AUTHLOAD. The following is a sample dependent region DFSESL:
  4. Specify the SSM (Subsystem Member) and IMSID values in the startup JCL for both the control region and appropriate dependent regions.

    In the JCL for the control region and the dependent regions that use Two-phase commit, you must specify the following values:

    IMSID=xxxx (typically begins with IMS) 


    xxxx and yyyy are allowed a maximum of four characters each. The xxxx and yyyy values are combined to form the name of the corresponding SSM (subsystem member) in the IMSVS.PROCLIB.

    For example, if the region JCL specifies the IMSID value as IMSA and the SSM value as TDP4, the SSM member name in IMSVS.PROCLIB is IMSATDP4.

  5. Define an SSM entry in IMSVS.PROCLIB for the control region and appropriate dependent regions.
    Define all TDPs destined to operate in Two-phase commit mode as external subsystems to the IMS control region and any dependent regions that support application transactions on the server. This is ensured by using SSM entries.

    One SSM can be defined for all regions (control and dependent). You can optionally define multiple SSMs. For multiple SSMs, you must define one for each dependent region where the dependent region for each SM defines the TDPs accessible to that region. In addition, the SSM for the control region defines all TDPs used in that system. The SSM entry in IMSVS.PROCLIB must be in the following form: TDPx,TDPx,DBCHCPI,,, where:

    TDPx is the tdpid for the Vantage server you are defining.

    IMS requires the comma characters to indicate omitted subparameters that are not used for the IMS interface.

    The syntax of the SSM entry is as follows:ssn,lit,esmt,,
    • ssn is the Subsystem Name. For the Teradata Attachment Facility, this field specifies tdpid (subsystem name).
    • lit is the Language Interface Token. This token, which is passed to the IMS external system support with the application call, identifies the external system with which the application is to communicate.

      For the Teradata Attachment Facility, this field must be the same as the subsystem name (ssn).

    • esmt is the Attachment Facility Initialization Module name. This module specifies which Attachment Facility modules must be loaded by IMS. For the Teradata Attachment Facility, this field must contain DBCHCPI. The release media includes a load module of this name to be placed in the AUTHLOAD library.
  6. Authorize IMS to TDP in the TDPPARM data set and then create new entries in the TDPPARM data set (described in TDPPARM Settings for Two-Phase Commit Processing) for each IMS control region that uses Two-phase commit protocol.
    The entries authorize each control region to TDP and are in the following form:

    imsjob is the job name for the IMS control region.

  7. Delete or comment out the TDP command, DISABLE IRF, in the TDPPARM data set.
    After the DISABLE IRF command is eliminated, the two TDP-internal sessions necessary for Two-phase commit processing are logged on automatically during TDP startup.