Effects of the element commands

The QUERY command shows the current status of an element. If OPERTUNE has modified the element, the original ZPARM value is also shown. If OPERTUNE did not modify the element, the query returns the current value and indicates that the element is not modified.

The SET command allows you to specify a new value for an element. When you stop OPERTUNE, elements changed with the SET command are reset to their original ZPARM values. Some elements, such as ARCALLOC or BP, have multiple fields that you can modify. If you leave a field blank, it remains unchanged.

Normally, elements that you changed with a SET command return to their ZPARM values when OPERTUNE is cycled. When you use the NORESET option, OPERTUNE does not reset the ZPARM value. As shown in the following figure, when you stop OPERTUNE, elements that have been changed with the NORESET option are not returned to their original ZPARM values.

Effects of the NORESET option on ZPARM values

image2018-12-19_15-17-43.png

RESET returns an element to its group value, or to its original ZPARM value if no group value exists. See Element-command-precedence for more information on the effects of a RESET command.

Note

A SET or RESET command that is issued while the subsystem is down is queued and takes effect when the subsystem restarts.

When you use OPERTUNE to change an element, the change is maintained when Db2 cycles. However, Db2 initially starts with the unchanged ZPARM values. After Db2 startup, OPERTUNE changes the element values, based on any groups, schedules, and individual element commands that were issued.

For example, if you use OPERTUNE to set ARCRETN to 9, and Db2 shuts down, OPERTUNE will reset ARCRETN to 9 after Db2 starts. The following figure shows the values of ARCRETN over time:

image2018-12-19_15-20-21.png

Note

During the restart of Db2, before changes made with OPERTUNE have been reapplied, the ZPARM values are still in effect. Although a restart of Db2 has little or no effect on most elements, it could result in an archive failure for the archive elements.

The purpose of OPERTUNE is to make dynamic changes without stopping Db2. Changes you want to make permanent should be made to the ZPARM values the next time you recycle Db2.

Related topic

Element-command-overview

 

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