June 25, 2013

DB2 10 Rebind Can Reduce CPU by 5, 10, even 20%

Getting the most from a new DB2 release typically requires some work on the part of customers, who must redesign their applications to take advantage of the latest features. Of course this effort is worthwhile, because it ultimately saves CPU, thus reducing the overall cost of the new database. 

DB2 10, however, works much more closely with the hardware to curtail both CPU and memory used by DB2 workloads. As a result, IBM says that DB2 10 for z/OS is capable, of out of the box, of giving customers a 5-10 percent CPU reduction for traditional workloads and as much as a 20 percent reduction for non-traditional workloads.

Many customers are realizing the 5-10 percent reductions simply by running the REBIND command to rebuild the internal DB2 control blocks used by that batch application.

Other performance enhancements with the latest version of DB2 include:


  • Improved index matching for OR and IN predicates -- Version 10 supports index matching on multiple IN-list predicates, list prefetch and predicate transitive closure for IN-list predicates.
  • Parallelism enhancements -- Version 10 eliminates many restrictions to parallelism and utilizes access methods that guarantee work is distributed more evenly across each parallel task.
  • Early application of stage 2 predicates.

A survey of DB2 for z/OS customers who recently participated in a DBI Software webinar showed about a 50-50 split between those on DB2 9 and those on DB2 10. This is good news for the DB2 community as well as vendors. Many current DB2 9 users only recently upgraded to it; now these customers are starting to plan migrations to DB2 10.

Some work remains, though. It seems that a small percentage of IBM customers are still on DB2 8 or earlier. While IBM no longer supports these releases, it does now allow customers to migrate directly from DB2 8 to DB2 10.

Incidentally, around the time I wrote that post in July 2012, I recall IBM saying that 25 percent of customers had moved to DB2 10, while about half were on DB2 9 and another 25 percent remained on DB2 8. If all these percentages are reasonably accurate, it seems possible that a fair number of DB2 customers have taken advantage of the DB2 8-to-DB2 10 skip migration. At the very least, it's a positive that most DB2 customers have at least advanced to DB2 9, while only a handful are still on prior releases.