Example of utility automation

Running reorganizations and copies on a scheduled basis instead of waiting until an object exceeds site guidelines can be costly in terms of wasted CPU cycles and work hours.

DASD MANAGER PLUS allows you to test for user-defined thresholds and, if exceptions occur, to take user-defined corrective action.

About BMCSTATS utility

The BMCSTATS utility collects the same statistics as RUNSTATS (plus some additional statistics) and writes the data to the Db2 catalog and to a historical database.

The historical database allows you to display statistics for the first, last, and previous times that you ran BMCSTATS on an object, analyze trends via reports and graphs, and perform 'what if' space estimation. You can use the additional statistics that BMCSTATS collects to determine when to run maintenance utilities on the physical objects.

For example, BMCSTATS calculates the REORGNLEVELS (the number of index levels that will be necessary if you reorganize the object). By comparing REORGNLEVELS with the current levels, you can determine whether reorganizing the index space will reduce the number of levels that the index requires.

In addition, BMCSTATS calculates REORGSPACE, which identifies the amount of space an object will consume if free space is reestablished (that is, if the object is redefined and reorganized). When the REORGSPACE of an object is greater than the current allocation, the reserved free space in an object has been used. Inserting new rows into that object causes page splits, fragmentation, and rapid disorganization. Resizing and reorganizing the object reestablishes the free space (as determined by the FREEPAGE and PCTFREE parameters on the table space or index space partition). Keeping the object tuned in this manner helps to ensure that application performance is not degraded. You can set this ratio as a threshold in the BMCTRIG utility.

About the utility-automation example

In this example, BMCTRIG evaluates thresholds and exceptions for all objects based on BMCSTATS data and generates corrective actions for the selected objects.

A corrective action is a copy, a reorganization, or a statistics-collection job step.

You can set up the automation by modifying the corrective actions and optionally modifying the threshold values. You then run BMCTRIG, which checks for objects that meet or exceed the designated thresholds and identifies those objects as exceptions. BMCTRIG automatically generates copy, reorganization, or statistics job steps for each object and action that was identified. BMCTRIG balances the workload across the number of jobs that the NUMJOBS option specifies (provided that the NUMJOBS option value is not 1).

If you choose to assign priorities to objects, actions, or thresholds, BMCTRIG generates work in priority order. You can then use a scheduler to run the generated jobs, or you can run them manually.

The following topics describe an example of the use of Utility automation: