Priority Scheduler - Teradata Database

Teradata Database Administration

Teradata Database
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Priority Scheduler

Priority Scheduler is a resource management tool that controls the dispersal of computer resources in Teradata Database. This resource management tool uses scheduler parameters that satisfy site-specific requirements and system parameters that depict the current activity level of Teradata Database. You can provide Priority Scheduler parameters to directly define a strategy for controlling computer resources.

You can use Priority Scheduler to:

  • Define a weighting system, based on user logon characteristics or Workload Definition (WD) rules, which prioritizes the database workload.
  • To define scheduling parameters and to monitor your current system activity.
  • Note: If TASM workload definition (Category 3) is active, no Priority Scheduler modifications are allowed through schmon.

    Design Goals

    Priority Scheduler includes default parameters that provide four priority levels; all users are assigned to one level.

    To take advantage of Priority Scheduler capabilities:

  • Assign users to one of the several default priority levels based on a priority strategy.
  • Define additional priority levels and assign users to them to provide a more sophisticated priority strategy.
  • Assign user who execute very response-sensitive work to a very high priority level to support Teradata Database applications.
  • For a description of the structure of and relationships between the scheduling components and parameters of Priority Scheduler, see “Priority Scheduler” in Utilities.

    When setting up for Priority Scheduler, Teradata recommends:

  • A low number of active AGs are preferred. 5 or 6 is a good target.
  • 1 or 2 Resource Partitions (RPs) to cover all user work.
  • A reasonably higher weight assigned to tactical query components, compared to those supporting other user work.
  • A demotion AG, if needed.
  • One possible RP setup is the following.







    Console utilities

    Tactical (optional)


    Highly-tuned tactical queries only



    All nontactical user-assigned work

    The recommended setup assumes that tactical queries are highly tuned and that they demonstrate the following characteristics: that all-AMP queries consume low levels of CPU per node.

    Bringing together all PGs doing nontactical work into a single RP makes it:

  • Easier to understand priority differences among AGs.
  • Simpler to setup and tune.
  • Less complex when faced with growth.
  • Easier when several PGs to share a single AG.