RE: Arrays and Performance

Jonathan,

Try 'guarding' your secondary file reads with an IF statement instead of using arrays/tables/indexes. With the '80/20 rule' there is a good chance you've already got the secondary file record and donât have to look it up again. A four hour run on a monthly telecom billing program was cut in half to two hours with just if statements guarding secondary file reads.

Alternatively try using SQL and let SQL determine how to access the secondary files. I just recently tested a SQL statement that duplicated an RPG program with one primary and two secondary files. The RPG program took twelve minutes and the SQL took two.

Paul Morgan

Principal Programmer Analyst
IS Supply Chain/Replenishment
508-253-3934


-----Original Message-----
From: rpg400-l-bounces@xxxxxxxxxxxx [mailto:rpg400-l-bounces@xxxxxxxxxxxx] On Behalf Of Jonathan Mason
Sent: Wednesday, August 04, 2010 6:36 AM
To: rpg400-l@xxxxxxxxxxxx
Subject: Arrays and Performance

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.

...

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