DB2® 9 for z/OS® is an exciting new version, with many improvements in performance and
little regression. DB2 V9 improves availability and security, as well as adds greatly to SQL and
XML functions. Optimization improvements include more SQL functions to optimize, improved
statistics for the optimizer, better optimization techniques, and a new approach to providing
information for tuning. V8 SQL procedures were not eligible to run on the IBM® System z9®
Integrated Information Processor (zIIP), but changing to use the native SQL procedures on
DB2 9 makes the work eligible for zIIP processing. The performance of varying length data
can improve substantially if there are large numbers of varying length columns. Several
improvements in disk access can reduce the time for sequential disk access and improve
data rates.
The key DB2 9 for z/OS performance improvements include reduced CPU time in many
utilities, deep synergy with IBM System z® hardware and z/OS software, improved
performance and scalability for inserts and LOBs, improved SQL optimization, zIIP
processing for remote native SQL procedures, index compression, reduced CPU time for data
with varying lengths, and better sequential access. Virtual storage use below the 2 GB bar is
also improved.
This IBM Redbooks® publication provides an overview of the performance impact of DB2 9
for z/OS, especially performance scalability for transactions, CPU, and elapsed time for
queries and utilities. We discuss the overall performance and possible impacts when moving
from version to version. We include performance measurements that were made in the
laboratory and provide some estimates. Keep in mind that your results are likely to vary, as
the conditions and work will differ.
In this book, we assume that you are somewhat familiar with DB2 V9. See DB2 9 for z/OS
Technical Overview, SG24-7330, for an introduction to the new functions.
In this book we have used the new official DB2 9 for z/OS abbreviated name for IBM
Database 2 Version 9.1 for z/OS as often as possible. However, we have used the old DB2 V9
notation for consistency when directly comparing DB2 V9 to DB2 V8 or previous versions.
