15.00 - schmon -b - 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 -b

Purpose  

The schmon -b option displays or sets Resource Partition parameters.

Syntax  

 

 

Syntax element

Description

-b

Sets or displays Resource Partition parameters. If no additional options are specified, schmon -b displays the parameters for Resource Partitions currently in use (those with defined parameters).

RP#

An integer from 0 through 4 that identifies the Resource Partition for which parameters will be set or displayed.

  • To set parameters for a Resource Partition, follow RP# with the RPNAME and weight specifications.
  • To view information about a specific Resource Partition, follow RP# with the -s or -S options, or with no options.
  • To clear all parameters for a specific Resource Partition, follow RP# with the -x option.
  • RPNAME

    The name of the Resource Partition.

    Resource Partition names that contain spaces must be within double quotation marks. For example, “RP ONE”.

    weight

     

    A numeric value used to compute a relative weight to determine the proportion of resources that the tasks controlled by the Resource Partition are to receive.

    limit

    A percentage limit on total CPU usage by all tasks controlled by the Resource Partition.

    The value ranges from 1 through 100.

    A value of 100 indicates that no limit is to be enforced.

    If limit is not specified, no limit is enforced, and any previously defined limit for the RP is removed.

    none

    Specifies that no limit is to be enforced. This is the default value for limit. It is the same as specifying 100.

    -s

    Displays Priority Scheduler data for all sessions controlled by the Resource Partition on the current node.

    -S

    Displays Priority Scheduler data for all sessions controlled by the Resource Partition on all nodes of the Teradata Database system.

    -T

    Displays tasks (threads) for the specified Resource Partition on the current node (the node from which schmon was invoked). Even when used in conjunction with the -S option, -T will display only task data for the current node.

    Note: The -T option should not be used for prolonged periods of time, because it can interfere with the normal operation of Priority Scheduler.

    The -T output includes the following columns:

  • Procqueue Tsk Addr: Kernel Task Context Block address
  • Tskid: Thread ID
  • Prio: OS priority
  • Session: Task session number
  • Request: Task request number
  • Tskuse: Task CPU resource usage
  • Tskterm: Session resource usage to weight ratio
  • # Delay: Task delay count due to CPU limits
  • Delay Time: Task total delay time due to CPU limits
  • -d

    Displays the differences in data between sequential runs of schmon. Use the delay [reps] option to control timing of automatic schmon runs.

    The following symbols precede numbers that appear in the output from the -d option.

  • For decimal numbers:
  • - (a minus sign) indicates the value has decreased by the indicated amount since the previous schmon run.
  • An unsigned decimal number indicates the value has increased by the indicated amount since the previous schmon run.
  • For task data (displayed if the -T option is used with the -d option):
  • n->     indicates a task has been moved from the control of AG n to the control of the displayed AG since the previous schmon run.
  • +     indicates a task is new, started since the previous schmon run.
  • -     indicates a task that ended since the previous schmon run.
  • *     indicates a task that has changed sessions or requests since the previous schmon run.
  • For examples of the -d option output, see “schmon -m” on page 745, and “schmon -s” on page 767.

    Note: The output of the -d option shows only those items for which data has changed since the previous schmon run.

    delay [reps]

    Causes schmon -b to run again automatically after a specified delay using the current session options. delay is a positive integer that specifies the number of seconds between schmon executions.

    Use the optional reps argument, a positive integer, to specify the number of times schmon should run. If reps is not specified, schmon runs indefinitely with delay seconds between executions. In this case, schmon can be stopped by pressing Ctrl-C or otherwise killing the schmon process.

    Note: The difference between time stamps of successive information displays may not precisely match the specified delay value due to the time required for the collection activity itself.

    -x

    Clears the parameters that define the specified Resource Partition, effectively deleting it from the system (though an empty group will still appear in the output of ‘schmon -b all’).

    The Resource Partition must not be referenced by any Performance Group.

    Usage Notes  

    For information on the settings displayed using the -b option, see “schmon -d” on page 739.

    The following apply to MPP configurations:

  • For the -S option:
  • The count of nodes is displayed.
  • Time information is displayed.
  • If a node is offline, it is not be included in the output, and the node count reflects this; however, information about this node being excluded is not displayed.
  • The following apply to SMP configurations:

  • Node count is not shown.
  • A status message that includes time of day is displayed.
  • No transient status messages are displayed.
  • Example  

    The following example shows a four-node MPP system.

    To display session data for Resource Partition 0 on the current node, type:

    schmon -b 0 -s

    The following appears:

    Stats: 3 node(s)  Mon Mar  8 15:02:06 2008
                                                Session Usage         Query Usage
      AG HostID    Session    Request #tsk  CPU(msec)   DSK(blk)  CPU(msec)   DSK(blk)  RP PG [PP]
     === ====== ========== ========== ==== ========== ========== ========== ========== === ===============
       1      0          0          0    9         60      10250         60      10250   0 L[0]
       2      0          0          0    2        640          0        640          0   0 M[0]
       4      0          0          0    1          1          0          1          0   0 R[0]

    Example  

    The following example shows a four-node MPP system.

    Note: PDE was not up on one of the nodes.

    To display session data for Resource Partition 0 on all nodes, type:

    schmon -b 0 -S

    The following appears:

    Stats: 3 node(s)  Mon Mar  8 15:02:06 2008
                                                Session Usage         Query Usage
      AG HostID    Session    Request #tsk  CPU(msec)   DSK(blk)  CPU(msec)   DSK(blk)  RP PG [PP]
     === ====== ========== ========== ==== ========== ========== ========== ========== === ===============
       1      0          0          0   19         80      20500         80      20500   0 L[0]
       2      0          0          0    6        790       5836        790      58360   0 M[0]
       4      0          0          0    3          5          0          5          0   0 R[0]

    Example  

    To limit CPU usage by tasks controlled by Resource Partition 1 to 40 percent of the total CPU available, type:

    schmon -b 1 RP1 50 40

    The following appears:

                            Resource Partitions (0 - 4)
    Id  Partition Name    Weight  Limit
     1  RP1                  50   none
     
    >>>>> Changed to:
     1  RP1                  50     40

    Example  

    To reset the limit to none on Resource Partition 1, type:

    schmon -b 1 RP1 50 none

    The following appears:

                            Resource Partitions (0 - 4)
    Id  Partition Name    Weight  Limit
     1  RP1                  50     40
     
    >>>>> Changed to:
     1  RP1                  50    none

    Example  

    To change the Resource Partition name, the relative weight, and the total CPU limit for Resource Partition 1, type:

    schmon -b  1 "RP NO 1" 100 none

    The following appears:

    Resource Partitions (0 - 4)
    Id  Partition Name    Weight  Limit
     1  rp1                  30     40
    >>>>> Changed to:
     1  RP NO 1             100    none