Availability Guide for Application Design

Designing Applications for Change
Availability Guide for Application Design—525637-004
10-35
Installing a New Program Version
Program Upgrade Without the REGISTERONLY or
NOREGISTER Options
Traditionally, a new version of a SQL program is typically developed on a development
system from where it is copied to the production system when the development and
test cycles are finished. On the production system, the program must be registered in
the SQL catalog and recompiled to refer to the set of SQL objects that reside on the
production system. After recompilation, the new execution plans are checked to see if
they have appropriate performance characteristics, even though this task was already
done on the development system against the test database.
To install the new version, it was, therefore, necessary to bring down the application
while the new version is compiled and the execution plans examined.
The REGISTERONLY and NOREGISTER options allow you to install your new
program version on the production system without recompiling; hence without
changing the execution plans that were optimized on the development system. To use
either of these options, the objects accessed by the program must have identical
schemas on the development and production systems.
Using the REGISTERONLY ON Option
The REGISTERONLY ON option implies that a new program installed on the
production system is to be registered in the catalog but not recompiled. The same
execution plans as generated on the development system are used. Since registering
a program takes considerably less time than compiling, a significant reduction in
application downtime is achieved.
Figure 10-6 on page 10-36 shows a situation in which the REGISTERONLY option is
used to help application program upgrade. Note that SQL objects are referred to by
DEFINEs so that the new objects on the production system can be accessed by setting
a DEFINE and using the similarity check.
Using the NOREGISTER ON Option
The NOREGISTER ON option not only allows a program to be moved from your
development system to the production system without recompilation, but also enables
the installation without registering the new program in the catalog.