RE: EJB versus RPG/COBOL

Joe,

I spent this week load testing performance of a large scale java-based
system running on the iSeries. The average across the system response on
RPG green screen apps has historically been about .5 seconds. The
results using jMeter for a mix of 10 users hitting a mix of the same the
same applications (actually much more functional) continuously was .71
seconds with an overall load on the system of about 20%. This load
allows a weeks worth of transactions to be put through in 30 minutes.
Increasing the load to 25 continuous simultaneous users results in 2.1
second response with about a 40% load but a weeks worth of transactions
would have been completed in about 20 minutes. Pushing it up to 50 users
to see if we could overwork the machine performance dropped to about 9
second response at 65% utilization. Actual concurrency testing with live
bodies also seems to back up these results. These tests were run during
slow business hours but still had to contend with production work. This
system is somewhat constrained by memory and to a lesser extent disk
arms.

You mention simple panels and I can assure you that is not the case
here. The database this runs against contains tables with > 100,000,000
records and the database I/O for several of these scripts involves
processing/summarizing > 30,000 records. The heavy lifting in those
cases is done by SQL, which is nice because the system puts those on
separate threads that help fully utilize the CPU. 

This site is running Tomcat/Hibernate/iBatis on a low-end 825 and
replaces a mixture of customized Software 2000 and custom ERP systems. I
haven't had a chance to do any performance tuning so I expect that these
numbers will get better. Still if I took 10-100 times RPG performance
these applications would not work.

David Morris

>>> joepluta@xxxxxxxxxxxxxxxxx 3/11/2004 7:05:33 PM >>>

And it required the bloated overkill of EJBs to make multiple-second
response time for a simple inquiry panel the norm.  On the other hand,
my clients get subsecond response time using RPG and Java on REAL
business applications.

And since the point evidently wasn't clear amongst all that LOFLOL, my
example program was showing that the Java->RPG call interface takes
two
milliseconds on a tiny little Model 270.  Now, since RPG is anywhere
from 10 to 100 times faster than Java in typical database
transactions,
that means that Java/RPG architecture will handily outperform EJBs.

If you want to do some real comparisons of performance, I'm willing to
discuss it.  But if you just want to take potshots at RPG, I advise
you
to find another list.

Joe