17.10 - Parallel Processing Return Codes - Parallel Transporter

Teradata® Parallel Transporter Application Programming Interface Programmer Guide

Product
Parallel Transporter
Release Number
17.10
Release Date
June 2021
Content Type
Programming Reference
Publication ID
B035-2516-061K
Language
English (United States)
Teradata PT supplies the following return codes for two types of synchronization:
  • TD_SYNC_TELINFO - Synchronize the TELINFO communication area from the main to the worker instances, and do not proceed until all instances reach this barrier.
  • TD_SYNC_Barrier - Do not proceed until all instances reach this barrier.

The Teradata PT parallel synchronization is main instance driven. All worker instances will receive the same synchronization return code in the same phase. The main instance, however, may receive a different synchronization return code. In these cases, the action taken should follow the synchronization code returned by the main instance. The following table lists possible synchronization return code combinations and the proper action to take.

Synchronization Return Code Combinations and Suggested Actions 
Received by Main Received by Worker Suggested Action
TD_SYNC_Barrier TD_SYNC_Barrier Call the method again which returned the barrier code after all instances reach this barrier.
TD_SYNC_Barrier TD_END_Method Main calls the method again which returned the barrier code. Workers wait to call the next method until Main receives TD_END_Method.
TD_SYNC_TELINFO TD_SYNC_Barrier Main calls the GetTELINFO function to get the TELINFO area and passes a copy of the TELINFO area to each of the workers. Workers call the PutTELINFO function to process the main's TELINFO area. Main and workers call the method again which returned the barrier code after all instances reach this barrier and after TELINFO area has been synchronized.
TD_SYNC_TELINFO TD_SYNC_TELINFO Main calls the GetTELINFO function to get the TELINFO area and passes a copy of the TELINFO area to each of the workers. Workers call the PutTELINFO function to process the main's TELINFO area. Main and workers call the method again which returned the barrier code after all instances reach this barrier and after TELINFO area has been synchronized.
TD_END_Method TD_END_Method Proceed to next method after all instances receive TD_END_Method.

Usage Notes

  • The main instance job must be started before starting the worker instance jobs
  • The CLIv2 environment variable THREADONOFF must be set to one for running the Teradata PT multi-threaded application. See Teradata® Call-Level Interface Version 2 Reference for Workstation-Attached Systems, B035-2418 for details about this variable.