Hi Paul,
Among other things, unless there's been a recent change, Java is not an
ILE participant. I would go further than Dieter and run Java on a separate
server. Among other things you can stay up to date with the latest and
throw tons of cheap memory at it. JTOpen provides everything you need for
AS/400 communication and calls.
Depending on what version you're running, I have a suggestion. I had a
series that ran batch reports along with lots of other applications. The
version I ran still had async garbage collection, which sounds like a great
idea but wasn't implemented very well. At times things came to a complete
halt. Turned out the system was starting another async collection before
the previous one ended, and I believe they got into contention. There
wasn't much I could do about it because the reports were third party and I
had no control over them.
I was about to force then to go to a single threaded queue ( not job
queue, just queue up the reports ) when admin "found" 8 gigs of extra
memory. They added that to the pool and things worked after that. But
that's an expensive solution in several ways.
Anyhow, I'd suggest pausing the job periodically during its run and see
if that allows things to unclog. Obviously there's some contention or other
work going on to cause the slowdown.
HTH, or gives some ideas.
Joe Sam
Joe Sam Shirah - www.conceptgo.com (904) 302-6870
conceptGO - Consulting/Development/Outsourcing
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-----Original Message-----
From: Steinmetz, Paul
Sent: Monday, June 22, 2015 3:04 PM
To: 'java400-l@xxxxxxxxxxxx'
Subject: RE: Java batch job performance issue
Dieter,
< A Java application ist started via QShell or QP2Term and programm java.
What you are describing is looking like some Java, RPG, CLLE mix. What are
you trying to accomplish, needing a mix of those three languages? That's far
away from all best practices and as you noticed yourself, you will get lots
of problems, you won't have with any of those languages by itself.>
Why should you not call Java from an RPGLE or CLLE pgm?
< But anyway best practice in Java is not to mix up Java with JNI for
applications. JNI is designed for the implementation of the JVM and the Java
Tools (java, javac, jar ...) not for writing applications.>
Again, why best practice?
Programmer added code to free up local Java objects.
Big improvement, but still loses performance over time.
"The job ran approx. 1 million API calls in 20 hours. I put in new code to
free up local Java objects so the garbage collector makes note of them.
The heap size was cut in half and it processed faster. The original one I
ran on Tuesday - Wednesday took 6 hours 15 minutes to perform the first
400000. This one performed the 400000 in 3 hours 7 minutes.
However, it still appears to lose processing speed over time. At the start
the job will perform 60 API calls per second. At the end, it only does
about 6 API calls per second."
Paul
-----Original Message-----
From: JAVA400-L [mailto:java400-l-bounces@xxxxxxxxxxxx] On Behalf Of D*B
Sent: Saturday, June 20, 2015 5:17 AM
To: java400-l@xxxxxxxxxxxx
Subject: Re: Java batch job performance issue
<Paul>
We are testing our first Java application</Paul> <Paul> The process is
called from an RPGLE pgm, Java is initialized in CLLE pgm.
</Paul>
A Java application ist started via QShell or QP2Term and programm java. What
you are describing is looking like some Java, RPG, CLLE mix. What are you
trying to accomplish, needing a mix of those three languages? That's far
away from all best practices and as you noticed yourself, you will get lots
of problems, you won't have with any of those languages by itself.
Java on AS/400 (and all compatible systems) is optimized for server java, in
other words: the startup of a JVM is rather slow (compared to Wintel and
Co.), if it is once up and running speed is ok for older JVMs and good for
J9 JVM. Compared to native workload each JVM needs much more ressources than
5250 or RPG/CL Batch and the JNI support of the RPG compiler is rather
buggy. But anyway best practice in Java is not to mix up Java with JNI for
applications. JNI is designed for the implementation of the JVM and the Java
Tools (java, javac, jar ...) not for writing applications.
If you are really needing RPG/Java interaction, an asynchronous approach
(RPG talking to a Java Server Job via DataQ or socket connect) would be by
far easier and better. Feel free to use my OpenSource appserver4rpg, it's
the base layer for ArdGate and CommandGate and extendable.
D*B
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