We migrated from DB2 V7.0 to DB2 V8.1. What will be the impact on current applications after migration? If there is any impact on current applications, what steps do I have to
follow to overcome them?
QUESTION POSED ON: 06 JAN 2005
QUESTION ANSWERED BY:
Craig Mullins
Well, you do not specify on which platform your DB2 is running, so I will
provide a broad overview as an answer. In general, most DB2 migrations will
have only light to moderate impact on existing applications. However, if you
are rebinding all of your application programs as a result of the migration,
then the impact can be considerable. Be sure to double-check all access
paths of all SQL statements in all programs that have been rebound. Any
access path that changes could negatively impact performance. Of course, the
hope is that the performance impact will be positive, but that is not
guaranteed. New versions of DB2 generally improve the capabilities of the
optimizer and therefore the tendency is for performance to improve at the
macro level, but at the micro level (that is, for a single SQL statement)
performance could degrade.
Additional impacts of a migration include improvement to the availability,
serviceability and managability of the databases used by the applications.
Additional utility functionality, available memory, and parameters can
produce a positive impact. However, such an impact is unlikely to be
experienced unless changes are made to existing procedures. For example, to
take advantage of the availability gains possible from data partitioned
secondary indexes you would have to convert existing indexes to the new
format (note: I am not necessarily suggesting you do this). On the other
hand, if you are running DB2 for z/OS and migrate to V8, your system might
improve because you can immediately take advantage of the virtual storage
constraint relief provided in this version.
Of course, much also will depend on the applications for which you are using
DB2. How were they written and what are they doing? As you can see, there is
no short answer to your question. I would suggest that you download the
what's new and intro manuals for the DB2 V8 platform you are using:
For z/OS download:
For Linux, Unix, Windows download:
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