16.10 - Sessions and Instances - Parallel Transporter

Teradata Parallel Transporter Reference

Product
Parallel Transporter
Release Number
16.10
Published
July 2017
Content Type
Programming Reference
Publication ID
B035-2436-077K
Language
English (United States)

Because the Stream operator uses Teradata SQL sessions in its communication with Teradata Database, it does not use Teradata Databaseload slots. The Stream operator provides continuous updates using row level locking, allowing constant load operations in the background during normal system use.

Both a minimum and a maximum number of sessions can be used by the Stream operator. The minimum specification is one. The default is one session for each operator instance.

The number of sessions is evenly distributed among the number of operator instances. If 20 sessions are requested and four instances of the operator are invoked, then each instance will receive five of the sessions.

Other Session Limits

The values that you specify with the Stream operator MinSessions and MaxSessions attributes are not the only factors that limit the number of sessions that the Stream operator establishes with the Teradata Database. The other limiting factors are:

  • The platform limit on the maximum number of sessions per application.
    • On network-attached client systems for UNIX, Linux, and Windows systems, this value is defined in the COP Interface software 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.
    • On mainframe-attached z/OS client system, use the TDP SET MAXSESSIONS command to specify a platform limit.
  • The limit of the network protocol software on network-attached systems.

When the Stream operator executes, the actual session limit is determined by the first limiting factor that is encountered.