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How to Manage Prestart Jobs in New Navigator

One of the latest features in New Navigator is the ability to display active prestart jobs. I’ve written extensively about prestart jobs since it can be difficult to understand what these jobs are doing. Some of my earlier articles, such as subsystem configuration, prestart job tuning and client special registers, aid in understanding what prestart jobs are doing as well as what applications are using those prestart jobs.

Now, with New Navigator, you have another way to understand and manage your prestart jobs with the Work Management Active Prestart Jobs task, as shown in Figure 1 below.

Work management menu with "active prestart jobs" highlighted
Figure 1. The Work Management Active Prestart Jobs task.

When you display active prestart jobs, you will have a table with every active prestart job entry on your partition. You can filter as needed, perhaps by subsystem. The information presented is similar to that of the Display Active Prestart Jobs (DSPACTPJ) command, showing the statistics for each prestart job entry in each subsystem.

However, with DSPACTPJ, you can only review the statistics for one prestart job entry at a time; with Active Prestart Jobs, you can easily review the statistics for all prestart job entries you define. The prestart job statistics are very helpful for tuning your prestart job entries.

I strongly recommend periodically tuning your prestart job entries. Workloads change over time and it’s best to adjust these entries to match current environmental demands.

When I tune prestart job entries, I always look at the “in use” statistics: Current/average/peak prestart jobs in use. To make this easier, I move the columns to the left, as shown in Figure 2 below.

Current, average and peak in use jobs displayed in the active prestart jobs table
Figure 2. Moving columns to the left.

This screen capture shows all the prestart job entries in the DAWNMAY subsystem with the current statistics. From here, I can easily drill down to change the prestart job entry, remove the prestart job entry or view the properties of the prestart job entry, as shown in Figure 3 below.

How to change, remove or view properties of a prestart job entry
Figure 3. Drill down to change the prestart job entry, remove the prestart job entry or view the properties of the prestart job entry.

This makes it very easy to tune my prestart job entries; I can see the current statistics in the table, make a quick note of the current/average in use (peak in use may be artificially high), then drill down to the Change prestart job entry… task to adjust the initial jobs (INLJOBS), additional jobs (ADLJOBS) and threshold (THRESHOLD) parameters as needed. When you change a prestart job entry, the change takes effect over time as the jobs are reused, ended or started as defined by the prestart job entry.

Also note on my above screen capture of active prestart jobs that I gave the prestart job a different name. The JOB parameter on the prestart job entry defaults to *PGM, which gives the job the same name as the program; e.g., QZDASOINIT. But if you have a lot of different applications that use the same prestart job types (database, remote command, etc.), separating the different uses by subsystem and specifying a name on the JOB parameter can make it easier to understand more specifically what application is using that particular prestart job. Note that the JOB parameter is only available on the ADDPJE or CHGPJE commands and not on the New Navigator GUI.