Sessions and Instances - Parallel Transporter

Teradata® Parallel Transporter Reference

Parallel Transporter
Release Number
February 2022
English (United States)
Last Update
Product Category
Teradata Tools and Utilities

The Update operator will connect one main (control) SQL session and one auxiliary SQL session, in addition to the data sessions. The main SQL session is responsible for executing SQL statements pertaining to utility work. The auxiliary session is used for creating and maintaining a restart log table for recovery purposes.

A minimum and a maximum number of sessions (the session limits) can be specified for the Update operator.

Consider the following usage notes:
  • The maximum sessions connected can never exceed the number of available AMPs in the system, even if a larger number is specified.
  • The default is one session per available AMP.
  • For the MinSessions attribute, the minimum specification is one.
  • The MaxSessions attribute can be set to a number smaller than the number of AMPs on the database server if fewer sessions are suitable for the job.
  • Network protocol software might also impose limits on workstation-attached systems.
  • Platform limits for maximum sessions per application differ:
    • On a mainframe-attached z/OS client system, use the TDP SET MAXSESSIONS command to specify a platform limit.
    • On workstation-attached client systems for UNIX, Linux, and Windows systems, this value is defined in the CLI file, clispb.dat, under the max_num_sess variable.
    • On mainframe-attached z/OS client systems, this value is defined in the HSHSPB parameter under the IBCSMAX setting.

The max_num_sess value in the clispb.dat file (or HSHSPB) specifies the total number of sessions allowed to be connected by a single application at one time. The max_num_sess pertains to all sessions connected, both SQL and data loading.