Specifying exceptions using the Exception Threshold data set editor

Exceptions are specified as threshold values in an Exception Threshold data set. When exception processing is active, Db2 instrumentation data is checked against these values and fields that contain values outside the specified thresholds are reported.

About this task

This topic describes how to specify threshold values with the Exception Threshold data set editor, which is used to set and maintain thresholds in an Exception Threshold data set.

The threshold values in the Exception Threshold data set can also be modified by means of the exception profiling method, which uses a sample of Db2 instrumentation data to calculate and set individual threshold values in the Exception Threshold data set. Refer to Exception profiling for more details. For more details about the Exception Threshold data set and a sample data set that can be used to get started, refer to Exception Threshold data set.

The Exception Threshold data set editor is accessed indirectly from the Data Set Maintenance Menu (DGOPMENU, (Figure 1).
Figure 1. Selecting Maintain Exception Threshold data set

DGOPMENU                   Data Set Maintenance Menu

Select one of the following.

1  1. Maintain exception thresholds
   2. Maintain correlation translations
   3. Maintain time zone information
   4. Maintain MAINPACK definitions

Exception data set
'DGO710.THRESH'_______________________

DPMPARMS data set
'DGO710.DPMPARMS'_____________________






Command ===> __________________________________________________________________
 F1=Help    F2=Split   F3=Exit    F9=Swap   F12=Cancel

Type 1 in the input field to select Maintain exception thresholds, and type the name of your Exception Threshold data set on the line below Exception data set.

Press Enter. The Exception Threshold Category Selection panel is displayed, as shown in Figure 2.
Figure 2. Exception Threshold Category Selection panel

 DGOPXDS1           Exception Threshold Category Selection
 Command ===> ___________________________________________________________

 Select one or more categories, then press Enter.  Overtype with space to
 deselect any category.  Request EXIT when complete.

     Category
 /   Elapsed, CPU and Waiting Times per Plan Execution
 _   Elapsed, CPU and Waiting Times per Program Execution
 _   CPU Times per Address Space
 _   SQL Statements per Plan Execution
 _   SQL Statements per Program Execution
 _   SQL Statements per System
 _   Subsystem Events per Plan Execution
 _   Subsystem Events per System
 _   Locking Activity per Plan Execution
 _   Locking Activity per System
 _   RID List Processing per Plan Execution
 _   RID List Processing per System
 _   Query Parallelism per Plan Execution
 _   Query Parallelism per System
 _   Buffer Pools Activity per Plan Execution
 _   Buffer Pools Activity per System
 _   Distributed Activity per Location per Plan Execution
 _   Distributed Activity per System
 _   Distributed Activity per Location per System
 _   IFI and Data Capture Activity per Plan Execution
 _   IFI Activity per System
 _   EDM Pool Activity per System
 _   Open/Close Activity per System
 _   Plan/Package Processing per System
  F1=Help    F2=Split   F3=Exit    F7=Up      F8=Down    F9=Swap   F12=Cancel
This panel shows the categories of exception threshold fields from which you can choose. The name of the category indicates the area where the exception applies:
  • … per Plan … or … per Program … exceptions are reported in Accounting
  • … per System … or … per Address Space… exceptions are reported in Statistics

You can select any number of categories by typing a forward slash (/) or S in the selection field.

Fields that have previously been selected are marked by a greater than symbol (>). If you overtype the symbol in front of a category with a blank, the underlying selections are not deleted, but they are not used when exception reports are generated. To activate the category, select it again.

As an example, the Elapsed, CPU and Waiting Times per Plan Execution field is selected in Figure 2. When you press Enter, the Exception Threshold Field Selection panel is displayed, which shows all fields associated with this category, as shown in Figure 3.
Figure 3. Exception Threshold Field Selection panel

 DGOPXDS2           Exception Threshold Field Selection
 Command ===> ___________________________________________________________

 Select one or more fields, then press Enter.  Overtype with space to
 deselect any field.  Request EXIT when complete.

 Field category  . . : Elapsed, CPU and Waiting Times per Plan Execution

    Field     Description
 >  ADCPUT    CPU time in application (Class 1)
 /  ADRECETT  Elapsed time in application (Class 1)
 _  ADTWTAP   Total wait time in application (Class 1)
 _  ADDb2ETT  Elapsed time in Db2 (Class 2)
 _  ADDBBCPUT CPU time in Db2 (Class 2)
 _  ADTWTDB   Total wait time in Db2 (Class 2)
 _  ADTSUST   Total Class 3 suspensions time
 _  ADTSUSC   Total Class 3 suspensions
 _  QWACAWTL  Lock/latch suspensions time (Class 3)
 _  ADLLSUSC  Lock/latch suspensions (Class 3)
 _  QWACAWTI  Synchronous I/O susp. time (Class 3)
 _  ADIOSUSC  Synchronous I/O suspensions (Class 3)
 _  QWACAWTR  Other read I/O susp. time (Class 3)
 _  ADARSUSC  Other read I/O suspensions (Class 3)
 _  QWACAWTW  Other write I/O susp. time (Class 3)
 _  ADAWSUSC  Other write I/O suspensions (Class 3)
 _  QWACAWTE  Serv.task switch susp. time (Class 3)
 _  ADSTSUSC  Serv.task switch suspensions (Class 3)
 -- End of Items --

  F1=Help    F2=Split   F3=Exit    F7=Up      F8=Down    F9=Swap   F12=Cancel

This panel shows all fields in this category. Fields that have been selected previously are marked by a greater than symbol (>) and sorted to the top.

Select a field for which you want to specify the exception thresholds. Type a forward slash (/) or S in the selection field and press Enter. The Exception Threshold Field Details panel is displayed (Figure 4).

Figure 4. Exception Threshold Field Details

 DGOPXDSN            Exception Threshold Field Details
 Command ===> ______________________________________________________________

                                                               ENTRY 1 OF 1

 Category  . . . . . : Elapsed, CPU and Waiting Times per Plan Execution
 Field ID  . . . . . : ADRECETT
 Description . . . . : Elapsed time in application (Class 1)



 Active  . . . . . . . . . . . . . 1  1=Yes   2=No

 By  . . . . . . . . . . . . . . . 1  1=Total   2=Minute   3=Second
                                      4=Commit  5=Thread

 Compare operator  . . . . . . . . <  <=Less than >=Greater than
 Warning threshold . . . . . . . . 4
 Problem threshold . . . . . . . . ____________

 Local location  . . . . . . . . . *
 Group name  . . . . . . . . . . . *
 Subsystem ID  . . . . . . . . . . *
 Member name . . . . . . . . . . . *
 Requester location  . . . . . . . *
 Connect . . . . . . . . . . . . . *
 Planname  . . . . . . . . . . . . *
 Corrname  . . . . . . . . . . . . *
 Corrnmbr  . . . . . . . . . . . . *
 Primauth  . . . . . . . . . . . . *
  F1=Help      F2=Split     F3=Exit      F5=Add       F6=Delete    F7=Up
  F8=Down      F9=Swap     F10=Previous F11=Next     F12=Cancel

Use the Exception Threshold Field Details panel to specify the threshold criteria in the Exception Threshold data set for the field selected from the Exception Threshold Field Selection panel.

The top right-hand side of this panel shows the entry number for this specification. You can specify more than one entry for the same exception field by using different criteria. For example, you can specify different exception thresholds for different plans. Or you might want to specify different threshold values for different environments (such as batch, online, or CICS®).To add a new entry, you use the ADD command or F5 (Add). To view the different entries, use F10 (Previous) and F11 (Next). Remove entries that are no longer needed to avoid extra processing by using the DELETE command or F6 (Delete).

The first three fields in the panel show the category of the selected exception field, the field identifier, and the description of the field.

In this panel you can specify:
  • Whether you want this field to be Active when exception reports are run. If you do not want to use the exception field specification when you generate exception reports the next time, but want to keep the entry, specify 2 (No).
  • How you want the field value to be calculated before it is checked against the exception thresholds (By). If you want the value in the field used as is, without any calculation, specify Total. Alternatively, you can specify that the value for the field is divided by minutes, by seconds, or by the number of Commits, or you can specify that the exception threshold is checked for the average value per thread (this is especially useful in reports). The effect of these specifications varies according to the report or trace you produce.
  • The Compare operator. It can be greater than or less than the threshold.
  • The thresholds. You can specify two kinds of thresholds for a field: Warning threshold and Problem threshold. Specify a warning threshold value to alert you to potential problems and a problem threshold value to indicate a more serious condition.
  • The additional criteria for the data for which the exception thresholds apply.

    These criteria are useful if you want to specify different exception threshold values depending on the environment. For example, you might want to specify different Elapsed Time thresholds for online transactions and batch jobs, in which case you would supply a specific connection name in this panel, press F5 (Add), and specify a different connection name in the second panel.

    You can specify a generic name using an asterisk (*).

Usage Notes:
  • Specify the time value in seconds, for example, 90 to specify a threshold of 1 minute and 30 seconds.
  • Do not enter 2 or 3 in the By field for time values. Specifying By Minute or By Second only is appropriate for fields that are not time related.
  • For Accounting exception traces, By Thread has the same effect as Total because in an Accounting trace only one thread is used for one entry.
  • For Accounting exception reports, if you specify Total, the threshold is checked for each thread . If you specify By Thread, the threshold value is checked against the average of the threads that are reported in one entry.
  • The following applies to Statistics exception traces and reports:
    • If you specify By Minute or By Second, Db2 PE uses the value of the INTERVAL ELAPSED field in the HIGHLIGHTS block as a divisor to calculate the rate value that is to be checked against the defined threshold.
    • If you specify By Thread, the value of the THREADS field in the HIGHLIGHTS block is used as a divisor to calculate the rate value that is to be checked against the defined threshold.
    • If you specify By Commit, the value of the COMMITS field of the HIGHLIGHTS block is used as a divisor to calculate the rate value that is to be checked against the defined threshold.