15.00 - schmon -w - Teradata Database

Teradata Database Utilities

Product
Teradata Database
Release Number
15.00
Content Type
Configuration
Publication ID
B035-1102-015K
Language
English (United States)
Last Update
2018-09-25

schmon -w

Purpose  

The schmon -w option sets or displays the number of tasks available on each vproc for use by work requests assigned to Allocation Groups having the Expedite attribute.

Syntax  

 

Syntax element

Description

 

-w

Sets or displays the number of tasks available on each vproc for use by work requests assigned to Allocation Groups having the Expedite attribute.

Without options, schmon -w displays the current settings.

reserve

A number from 0 through 20, that indicates the number of AWTs reserved within each AMP for work requests assigned to Allocation Groups having the EXPEDITE attribute.

This reserve ensures that at least this specified number of AWTs will be ready to service a work request when it arrives. When the number of expedited work requests exceeds this reserve, arriving expedited work requests might be forced to wait in an input queue, depending on overall work load conditions. This reserve determines the minimum number of expedited work requests that will run concurrently.

This reserve, multiplied by three, is deducted from the general pool of AWTs and will impact the number of tasks available for normal non-expedited work requests.

Teradata recommends the following:

  • Initially select a low number for reserve (1-3).
  • Expedite only Allocation Groups supporting short, response-sensitive queries.
  • maximum

    A number between 1 and 999, inclusive, that indicates the maximum number of AWTs that can run at any time.

    The number of tasks that run might be less than this maximum, depending on the current limit. Since the special reserve work type supports new work, similar to MSGWORKNEW, one reasonable setting for the parameter is the same as the MSGWORKNEW maximum(50).

    Note: Since most systems have a practical limit of 80 AMP worker tasks per AMP that can be supported at any one time, the 999 value has no real function.

    Usage Notes  

    The Expedite attribute is defined by an Allocation Group. For more information see “Expedite Attribute” on page 716 and “AMP Worker Task (AWT) Reservations and Limits” on page 720.

    Consider scripting a set of schmon commands for each restoration and maintenance.

    Example  

    To display the number AWTs reserved within each AMP vproc for work requests assigned to Allocation Groups having the EXPEDITE attribute and the maximum number of AWTs that can run at any time, type:

    schmon -w

    The following appears:

                            AWT Expedited work type limits
     res   max
       0   999

    Example  

    To set the number AWTs reserved within each AMP vproc for work requests assigned to Allocation Groups having the EXPEDITE attribute and the maximum number of AWTs that can run at any time, type:

    schmon -w 5 10

    The following appears:

                            AWT Expedited work type limits
     res   max
       0   999
     
    >>>>> Changed to:
       5    10