This Db2 for z/OS News from the Lab blog entry was originally published on 2018-01-12.

By Haakon Roberts and Eric Radzinski.

Over the past several Db2 for z/OS versions, one of our focus areas has been CPU reduction. A big part of that effort has been to cut the cost of database management by further exploitation of z Systems Integrated Information Processors (zIIPs) in IBM utilities. For example, we enabled the offloading of index build in LOAD, REORG, and REBUILD INDEX in Version 8, of the UNLOAD phase of REORG in Version 9, of RUNSTATS in Db2 10, and of inline stats in Db2 11. As you're probably aware, CPU processing that occurs on zIIPs does not impact MLC license charges, so generally the more processing that occurs on zIIPs the better.

In keeping with this trend, we've recently enabled a portion of the RELOAD phase of the REORG and LOAD utilities to be offloaded to a zIIP, and we've done so without requiring changes to existing utility jobs. All Db2 11 and Db2 12 environments that have at least one zIIP configured with spare capacity will automatically experience this general purpose processor CPU time reduction after the related maintenance is applied. To give you some idea of the potential benefit, one client reported a 50% CPU reduction for REORG and 65% CPU reduction for LOAD.

To take advantage of these CPU savings, apply the PTFs for the following APARs:

• APAR PI73882 for Db2 11 and Db2 12, which enables zIIP offload for the RELOAD phase of the LOAD and REORG utilities
• APAR PI80243 for Db2 11 and APAR PI80310 for Db2 12, which enables zIIP offload for the RELOAD phase of the LOAD utility when the PARALLEL keyword is specified with SHRLEVEL NONE or SHRLEVEL REFERENCE

Again, as long as one or more zIIPs are installed and spare capacity exists on them, CPU time during the RELOAD phase will be reduced just by ensuring the above maintenance is applied. Another example of how the IBM Db2 utilities continue to focus on reducing the cost of running Db2.

Haakon Roberts is a Distinguished Engineer at the IBM Silicon Valley Laboratory in San Jose, California and the chief technical architect and strategist for Db2 for z/OS Utilities and Tools.

Eric Radzinski is a technical writer for Db2 for z/OS at the IBM Silicon Valley Laboratory in San Jose, California.