Re: Arrays and Performance

If you are looking at a significant investment in changing your applications
then I would strongly recommend you enlist the aid of a company
knowledgeable in the tradeoffs involved with different approaches. Your
question has no one "right" answer. It all depends on how you would answer a
variety of follow-on questions related to data sizes, access methods,
staticity of the data, sharing of the data across jobs, etc.
IBM Rochester can provide these types of services (as I used to be one of
the people you might have worked with there on such an endeavor), along with
(start of vendor response) my company Bruce Vining Services (end of vendor
response) and others.

What you have asked is not an easy question to answer (correctly) though
many of the potential answers will include moving from RPG/400 to ILE RPG.

Bruce
On Wed, Aug 4, 2010 at 5:35 AM, Jonathan Mason <
jonathan.mason@xxxxxxxxxxxxxxxx> wrote:

Hi All

We have a number of programs, some in RPG/400 and others in RPG IV, that
load reference data from various files into arrays in an attempt to
reduce the performance impact of multiple chains to database files.

The trouble with this approach is that the arrays are limited in size, a
maximum 9,999 elements in RPG/400 and 32,767 elements in RPG IV.

One thought was to use the arrays for the first however many records
would fit and then chain to the database file for the remaining records,
but there's concern about the performance impact of that approach.

An alternative is to make use of user indexes, which could provide a lot
more space for storing entries, but we're not sure on the performance
impact of that approach.

Does anybody have any knowledge of the performance benefits and pitfalls
of any of these approaches? What do others do when faced with the same
problem?

Thanks


Jonathan Mason


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