RE: RPG IV Performance

[Eric DeLong <Eric.DeLong@xxxxxxxxxxxxxxxxx>]

     Hi Lisa,
     
     You contractor seems to be applying some outdated reasoning to 
     reach his conclusions. While it is true that RPGIV executables are 
     larger than OPM executables, the increase in size does not adversly 
     affect performance. The RPGIV compiler does a much better job of 
     optimizing, and the resulting code will almost always run faster 
     than its OPM counterpart. RPGIV programs will use more storage than 
     OPM, so on undersized AS400, there could be issues relating to 
     memory management that could degrade performance, but if that were 
     the case, I would certainly hesitate to do ANY database triggers. 
     
     There have been several discussions on trigger performance in the 
     past. Some of it should still be in the archives. There's even some 
     sample code (written in RPGIV of course). I cannot recall anyone 
     ever claiming that RPGIII trigger programs outperform RPGIV. 
     
     good luck,
     Eric
     


______________________________ Reply Separator
_________________________________
Subject: RPG IV Performance
Author:  "Lisa.Abney@universalflavors.com" 
<SMTP:Lisa.Abney@universalflavors.com> at EXCHANGE
Date:    1/19/01 7:06 AM


Hi all!  I've just heard some rather negative performance things on RPG IV,
and 
wonder if anyone can give me some feedback on how true this might be.
     
We're working with a consulting company who is doing some performance
analysis 
on some of our programs.  They seem very knowledgeable, and I have a lot of 
confidence in what they've done up until now.  However, today they were
showing 
us a mock-up of a trigger program they want to use.  As they explained it,
this 
trigger program will be constantly running in the background for every user
on 
the system to monitor changes to two files, and will feed data to a dataque.
The
program they showed me was written in RPGIII, and I made my usual request to
an 
outside contractor that this be done in RPGIV.  His response was "Sure, if
you 
want the program size to be 5 - 10 times the size of an RPGIII program."
When I 
asked him to explain that, he only said that, in his experience, this is
always 
true, and that it would have a very negative performance.  I even mentioned 
removing observability (not that I really understand what that means, but I
just
read something the other day about that being a way to reduce program
size!), 
and he said that might move it down to 3 - 5 times the size of an equivalent

RPGIII program.  The program will only be about 50 - 100 lines of code.
     
Can someone explain if this is true, and, if so, why?  And, if true, what
does 
this really mean from a performance standpoint?
     
     
     
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