[rules-users] Out of Mem and thousand threads : Disabling JIT ?

Hi, I am using Drools for some time an I recently increased the number of rules and their complexity. I have now about 200 rules, for 700 x 200 facts (rules on a cartesian product on them). Since then, the computation of rules explodes with the following exception : java.lang.OutOfMemoryError: unable to create new native thread at java.lang.Thread.$$YJP$$start0(Native Method) [na:1.6.0_30] at java.lang.Thread.start0(Thread.java) [na:1.6.0_30] at java.lang.Thread.start(Thread.java:640) [na:1.6.0_30] at java.util.concurrent.ThreadPoolExecutor.addIfUnderMaximumPoolSize(ThreadPoolExecutor.java:727) ~[na:1.6.0_30] at java.util.concurrent.ThreadPoolExecutor.execute(ThreadPoolExecutor.java:657) ~[na:1.6.0_30] at org.drools.rule.constraint.MvelConstraint.jitEvaluator(MvelConstraint.java:232) ~[org-drools-drools-core-5.5.0.Final.jar:5.5.0.Final] at org.drools.rule.constraint.MvelConstraint.evaluate(MvelConstraint.java:197) ~[org-drools-drools-core-5.5.0.Final.jar:5.5.0.Final] at org.drools.rule.constraint.MvelConstraint.isAllowed(MvelConstraint.java:157) ~[org-drools-drools-core-5.5.0.Final.jar:5.5.0.Final] at org.drools.reteoo.AlphaNode.assertObject(AlphaNode.java:137) ~[org-drools-drools-core-5.5.0.Final.jar:5.5.0.Final] at org.drools.reteoo.SingleObjectSinkAdapter.propagateAssertObject(SingleObjectSinkAdapter.java:59) ~[org-drools-drools-core-5.5.0.Final.jar:5.5.0.Final] at org.drools.reteoo.AlphaNode.assertObject(AlphaNode.java:141) ~[org-drools-drools-core-5.5.0.Final.jar:5.5.0.Final] at org.drools.reteoo.SingleObjectSinkAdapter.propagateAssertObject(SingleObjectSinkAdapter.java:59) ~[org-drools-drools-core-5.5.0.Final.jar:5.5.0.Final] at org.drools.reteoo.AlphaNode.assertObject(AlphaNode.java:141) ~[org-drools-drools-core-5.5.0.Final.jar:5.5.0.Final] at org.drools.reteoo.SingleObjectSinkAdapter.propagateAssertObject(SingleObjectSinkAdapter.java:59) ~[org-drools-drools-core-5.5.0.Final.jar:5.5.0.Final] at org.drools.reteoo.AlphaNode.assertObject(AlphaNode.java:141) ~[org-drools-drools-core-5.5.0.Final.jar:5.5.0.Final] at org.drools.reteoo.SingleObjectSinkAdapter.propagateAssertObject(SingleObjectSinkAdapter.java:59) ~[org-drools-drools-core-5.5.0.Final.jar:5.5.0.Final] ... After Googling a bit, I saw that this is due to JIT compilation of my rules. For some reason, each one seem to create a Thread and ends up with thousands of them. First of all, I find a bit risky that the JIT compilation is fired by some *hardcoded *threshold : I was not expecting such a technical tricky optimization to randomly activate depending of my data. Anyway, I wanted to disable this JIT thing. I saw that the disabling is only available since *5.5.0.-final* right ? I have switched to that version but I can't seem to be able to disable it. I have tried both : *-Dmvel2.disable.jit=true* (which would not be a viable solution for production anyway : We can't rely on some settings of the server to ensure things work) And also this : *OptimizerFactory.setDefaultOptimizer("reflective"); *(found here<http://mvel.codehaus.org/Disabling+the+JIT+Compiler> ) Any help would be appreciated. Brgds, Raphael