Multiple agents can be used to copy a single large database object such as a table, a database, or a journal with the create or move command for jobs that use Teradata ARC or Teradata PT API by editing the XML file for the command.
- Add the <max_agents_per_task> element.
- Set the value of the <max_agents_per_task> element to an integer number greater than one, but less than or equal to the number of installed, online agents. This value corresponds to the maximum number of agents that are allocated for copying each database object in the job.
- Set the value of the <data_streams> element to an integer number greater than 1. Work is spread across multiple agents by assigning each agent one or more data streams.
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For Teradata PT API only, set the value of <source_sessions> and <target_sessions> to an integer number greater than or equal to the value of <data_streams>.
Teradata PT API distributes sessions among the data streams. Because each Teradata PT API data stream requires at least one source and one target session, the number of source and target sessions must be greater than or equal to the number of data streams.The parameter values for which all conditions must be true for Teradata ARC and Teradata PT API are:
Parameters Product max_agents_per_task > 1 Teradata ARC and Teradata PT API max_agents_per_task <= number-of-online-agents Teradata ARC and Teradata PT API data_streams > 1 Teradata ARC and Teradata PT API source_sessions >= data_streams Teradata PT API target_sessions >= data_streams Teradata PT API If you do not specify a value, Data Mover calculates <max_agents_per_task> dynamically for optimal performance.
The following table describes what occurs with different values for the <data_streams>, <max_agents_per_task>, <source_sessions>, and <target_sessions> parameters.Value Description <max_agents_per_task> is greater than the number of online agents. Teradata ARC and Teradata PT API:
Sets <max_agents_per_task> equal to the number of online agents.<data_streams> is greater than <max_agents_per_task> Teradata ARC and Teradata PT API:
Optimizes the distribution of the available data streams evenly among the online agents.<max_agents_per_task> is greater than the value of <data_streams>. The number of agents used for running a task is equal to the value of <data_streams>. <data_streams> and <max_agents_per_task> are not provided. Teradata ARC and Teradata PT API:
Optimal Data streams is first computed, then sets the value of <max_agents_per_task> equal to the computed <data_streams>.<source_sessions> or <target_sessions> is less than <data_streams>. Teradata PT API only:
Sets <source_sessions> or <target_sessions> equal to the number of data streams.<source_sessions> or <target_sessions> are not provided. Teradata ARC and Teradata PT API:
Sets <source_sessions> or <target_sessions> dynamically to provide optimal performance.<data_streams> is provided and <max_agents_per_task> is not provided. Teradata ARC and Teradata PT API:
Sets the value of <max_agents_per_task> equal to the <data_streams>.<data_streams> is not provided and <max_agents_per_task> is provided. Teradata ARC and Teradata PT API:
Optimal data streams is computed. If <max_agents_per_task> is specified and the value is less than or equal to the number of computed data streams, the specified value is used; otherwise, the <max_agents_per_task> value is set to match number of computed data streams.