Teradata Database Task Concurrency Limits
To ensure that the data remains accessible to users, Teradata Database enforces limits on the quantity of system resources that can be used by extract and load utilities. These limits affect use of the following operators:
Each time one of these operators is referenced in an APPLY statement counts as one task. Limits are controlled by two DBSControl settings:
The system counts the total number of tasks attempting to run concurrently and then the settings of the two fields are applied to that total, and task limits are enforced, where necessary.
To get a general idea of total concurrent Teradata PT tasks for your site, consider the following basic rules:
Keep in mind that job steps within a single job execute sequentially, so the maximum number of concurrent tasks in a single job is two.
Actual limits are subject to additional factors. For details on how to set the MaxLoadAWT and MaxLoadTasks fields in the DBSControl GDO, and how those settings will affect Teradata PT jobs, see the section on the DBSControl utility in Utilities: Volume 1 (A-K).