Tuning to improve memory use

Tuning sort processing

Specifying a value greater than 0 for the SORTNUM option tells UNLOAD PLUS that BMCSORT will control sort work allocations, which should eliminate sort work constraints.

The amount of multitasking that sort processing performs depends on the number of CPUs, the SMAX or MAXSORTS option value, the number of SORTWK data sets, and available memory. You might be able to improve memory usage by adjusting the SMAX or MAXSORTS option value or the number of SORTWK data sets.

Tuning when unloading objects with a large number of partitions

Unloading objects with a large number of partitions increase the potential for encountering such issues as performance problems and memory restrictions.

Use the following information to help you avoid these issues:

• Ensure that you have specified a region size that allows the system to allocate as much virtual storage as possible to the UNLOAD PLUS job. We recommend that you specify REGION=0M in the JOB or EXEC statement of your execution JCL.
• If you have specified REGION=0M and your unload job fails with a constrained resources error, consider unloading fewer partitions in a single job.
• When specifying the &PART variable, you should limit the number of dynamically allocated SYSREC data sets to no more than 300 to 500. This limitation is due to the amount of below-the-line storage that is available to the job step.
• If you are unloading a large number of partitions, consider lowering the value of the VOLCNT option from the default of 25 to avoid data set allocation limitations.