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I'm using Jess from Java.

I'd like to know if there exist any command and/or parameter that could help providing more memory to the Jess engine ?

Thank you, have a good day. Edouard

Edouard Batot
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  • http://docs.oracle.com/javase/7/docs/technotes/tools/windows/java.html . Start with -Xmx and -Xms – fvu Mar 13 '17 at 14:48
  • Done : 4GB each, thanks :) – Edouard Batot Mar 13 '17 at 14:58
  • I mean, this has been done ages ago, I need more space for Jess... – Edouard Batot Mar 13 '17 at 15:00
  • I assume that the Jess code is running in the same VM as the rest of your Java program, so specifying these parameters when starting Java should help. You can use JVisualVM to see what's going on in a JVM's memory and create a heap dump to see where the memory is being used. You may need to increase the heap size beyond 4G for all we know. – fvu Mar 13 '17 at 15:04
  • You are compiling and running you Java app with jess.jar in the classpath and there is nothing but Java classes being pulled in. It is fairly easy to run out of memory with a sufficiently large number of rules and facts, although the way you write your rules can make a big - very (!) big - difference. – laune Mar 13 '17 at 15:46
  • "You may need to increase the heap size beyond 4" this is harder... Increasing heapsize beyond 4G isn't always possible... is it ? (I have 32G on my comp and no way to go that high..) But thanks thanks, it's for a colleague and I SERIOUSLY hope he's tried before the xmxs args ! I'll get back. – Edouard Batot Mar 13 '17 at 15:49
  • [You can go beyond 4GB on a 64 bits system](http://stackoverflow.com/questions/1565388/increase-heap-size-in-java) and I assume that you're not running that kind of heavy duty programs on a decade old 32-bits only system, or on a 32 bits Java... – fvu Mar 13 '17 at 16:07
  • Suggesting to increase the heap memory without knowing the number and nature of the rules and the number of facts is very likely not going to help. Even if you avoid the OOM, you'll then complain about very slow performance. That's what a Rete network from sub-optimal rules may cause. – laune Mar 13 '17 at 16:28
  • Yes, but on a forum and tiny little coments like here, it is hard to get into semantics of the Jess Structure... I really appreciate your point laune, but I am not the guy to talk about it more thouroughly. I transmit your help to the interested one - and come back. Thanks fvu - I didn't realize their was such a difference lol. It's gona help on other projects :) – Edouard Batot Mar 13 '17 at 20:17

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