15.00 - schmon -t - Teradata Database

Teradata Database Utilities

Teradata Database
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schmon -t


The schmon -t option sets or displays Age Time, Active Time, and Dispatch Wait Time.



Syntax element




Sets or displays Age Time, Active Time, and Dispatch Wait Time.

If no additional options are specified, schmon -t displays the current settings. If any options are specified, all three options must be specified, regardless of operating system.


Age Time. The time period, in seconds, over which recent Allocation Group resource usage is measured.

The range is 1 to 60 seconds. The default is 60 seconds.


Active Time. The time period, in seconds, during which an Allocation Group is considered active if any task assigned to the Allocation Group has been scheduled. Inactive Allocation Groups are not included in resource consumption calculations.

The range is 1 to 1800 seconds. The default is 61 seconds.


Note: This option is meaningful only on Linux. The Dispatcher Wait Timer is also known as the anti-starvation mechanism.

Dispatch Wait Time. The maximum period of time, in seconds, that a task can wait in a ready-for-execution state in a dispatch queue without receiving access to a CPU. After this time, the task priority is increased and its wait period is re-initialized.

The range is -1 through 127. The default is 4 seconds.

The following values apply:

  • 0 specifies that the Dispatch Wait Time be set to the factory default of four seconds.
  • -1 specifies that the Dispatch Wait Timer be disabled.
  • Note: The Dispatch Wait Timer is enabled by default.


    Teradata recommends that you do not use this setting unless absolutely necessary.

  • 1 -127 specifies a wait period in seconds.
  • Example  

    To view the current settings, type:

    schmon -t

    The following appears:

    Age Time(sec):   60  Active Time(sec):   61  Disp Age(sec):   5

    To change the settings, type:

    schmon -t 30 31 5

    The following appears:

     Age Time(sec):   60  Active Time(sec):   61  Disp Age(sec):   0
    >>>>> Changed to:
     Age Time(sec):   30  Active Time(sec):   31  Disp Age(sec):   5