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This looks different to what was fixed in 4.0.4. I'm cc'ing brockm to
get his feedback as it looks like an MVEL bug on accessors.<br>
<br>
Mark<br>
Fernando Meyer wrote:
<blockquote
cite="mid:bc9e67320801220548k7bc226a1s365ac3d9a7ec99ea@mail.gmail.com"
type="cite">Hi Ingomar, <br>
<br>
Which drools version are you using? We made improvements on 4.0.4, that
fixes concurrency issues on mvel core, so if you aren't using it please
do an update and try test against your environment. <br>
<br>
Please let me know if your problems go away when you upgrade.<br>
<br>
Thanks <br>
<br>
<div class="gmail_quote">On Jan 22, 2008 11:13 AM, Ingomar Otter <<a
moz-do-not-send="true" href="mailto:ingomar.otter@valtech.de">ingomar.otter@valtech.de
</a>> wrote:<br>
<blockquote class="gmail_quote"
style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
<div>
<div>
<div style="">Folks,
<div>I am currently trying to scale our implementation by farming
out request into mutliple threads. I am on a 4 CPU Mac.</div>
<div>A few things I am wondering about:</div>
<div>1. Although I see an increase in CPU load when going from
single to multi-threaded processing the throughput increased
marginally. I am pretty sure that my measurements are correct. I have
checked the GC and this is not the source of congestion. My question
here is whether Drools is using lot's of synchronization that may
explain this. </div>
<div>2. When I share the RuleBase accross threads (which I think is
valid?) I get interesting errors during execution. eg:</div>
<div>
<div style="margin: 0px; min-height: 15px;"><br>
</div>
<div style="margin: 0px; color: rgb(255, 0, 0);"><span
style="text-decoration: underline; color: rgb(0, 0, 128);">org.drools.RuntimeDroolsException
</span>: Exception executing predicate
org.drools.base.mvel.MVELPredicateExpression@bb981e</div>
<div style="margin: 0px; color: rgb(255, 0, 0);"><span
style="white-space: pre;"></span>atorg.drools.rule.PredicateConstraint.isAllowedCachedRight(<span
style="text-decoration: underline; color: rgb(0, 0, 128);">
PredicateConstraint.java:246</span>)</div>
<div style="margin: 0px; color: rgb(255, 0, 0);"><span
style="white-space: pre;"> </span>at
org.drools.common.TripleBetaConstraints.isAllowedCachedRight(<span
style="text-decoration: underline; color: rgb(0, 0, 128);">TripleBetaConstraints.java:200</span>)</div>
<div style="margin: 0px; color: rgb(255, 0, 0);"><span
style="white-space: pre;"><br>
</span>atorg.drools.reteoo.JoinNode.assertObject(<span
style="text-decoration: underline; color: rgb(0, 0, 128);">JoinNode.java:150</span>)</div>
<div style="margin: 0px; color: rgb(255, 0, 0);"><span
style="white-space: pre;"><br>
</span>atorg.drools.reteoo.CompositeObjectSinkAdapter.propagateAssertObject(<span
style="text-decoration: underline; color: rgb(0, 0, 128);">CompositeObjectSinkAdapter.java:318</span>)</div>
<div style="margin: 0px; color: rgb(255, 0, 0);"><span
style="white-space: pre;"></span>atorg.drools.reteoo.ObjectTypeNode.assertObject(<span
style="text-decoration: underline; color: rgb(0, 0, 128);">ObjectTypeNode.java:153</span>)</div>
<div style="margin: 0px; color: rgb(255, 0, 0);"><span
style="white-space: pre;"> </span>at
org.drools.reteoo.Rete.assertObject(<span
style="text-decoration: underline; color: rgb(0, 0, 128);">Rete.java:175</span>)</div>
<div style="margin: 0px; color: rgb(255, 0, 0);"><span
style="white-space: pre;"></span>atorg.drools.reteoo.ReteooRuleBase.assertObject
(<span style="text-decoration: underline; color: rgb(0, 0, 128);">ReteooRuleBase.java:192</span>)</div>
<div style="margin: 0px; color: rgb(255, 0, 0);"><span
style="white-space: pre;"> </span>at
org.drools.reteoo.ReteooWorkingMemory.doInsert(<span
style="text-decoration: underline; color: rgb(0, 0, 128);">ReteooWorkingMemory.java:71</span>)</div>
<div style="margin: 0px; color: rgb(255, 0, 0);"><span
style="white-space: pre;"><br>
</span>at org.drools.common.AbstractWorkingMemory.insert(<span
style="text-decoration: underline; color: rgb(0, 0, 128);">AbstractWorkingMemory.java:909</span>)</div>
<div style="margin: 0px; color: rgb(255, 0, 0);"><span
style="white-space: pre;"><br>
</span>atorg.drools.common.AbstractWorkingMemory.insert(<span
style="text-decoration: underline; color: rgb(0, 0, 128);">AbstractWorkingMemory.java:881</span>)</div>
<div style="margin: 0px; color: rgb(255, 0, 0);"><span
style="white-space: pre;"><br>
</span>atorg.drools.common.AbstractWorkingMemory.insert(<span
style="text-decoration: underline; color: rgb(0, 0, 128);">AbstractWorkingMemory.java:682</span>)</div>
<div style="margin: 0px; color: rgb(255, 0, 0);"><span
style="white-space: pre;"><br>
</span>atxxxx.DroolsPD.validate(<span
style="text-decoration: underline; color: rgb(0, 0, 128);">DroolsPD.java:66</span>)</div>
<div style="margin: 0px; color: rgb(255, 0, 0);"><span
style="white-space: pre;"> </span>at xxxx.DroolsMTRunner.run(<span
style="text-decoration: underline; color: rgb(0, 0, 128);">DroolsMTRunner.java:30</span>)</div>
<div style="margin: 0px; color: rgb(255, 0, 0);"><span
style="white-space: pre;"> </span>at java.lang.Thread.run(<span
style="text-decoration: underline; color: rgb(0, 0, 128);">Thread.java:552</span>)</div>
<div style="margin: 0px; color: rgb(255, 0, 0);">Caused by: <span
style="text-decoration: underline; color: rgb(0, 0, 128);">org.mvel.CompileException</span>:
cannot invoke getter: getSAClass [declr.class: xxx.AbstractSA;
act.class: null]</div>
<div style="margin: 0px; color: rgb(255, 0, 0);"><span
style="white-space: pre;"></span>atorg.mvel.optimizers.impl.refl.GetterAccessor.getValue(<span
style="text-decoration: underline; color: rgb(0, 0, 128);">
GetterAccessor.java:52</span>)</div>
<div style="margin: 0px; color: rgb(255, 0, 0);"><span
style="white-space: pre;"> </span>at
org.mvel.optimizers.impl.refl.VariableAccessor.getValue(<span
style="text-decoration: underline; color: rgb(0, 0, 128);">VariableAccessor.java:39</span>)</div>
<div style="margin: 0px; color: rgb(255, 0, 0);"><span
style="white-space: pre;"><br>
</span>at
org.mvel.ast.VariableDeepPropertyNode.getReducedValueAccelerated(<span
style="text-decoration: underline; color: rgb(0, 0, 128);">VariableDeepPropertyNode.java:22</span>)</div>
<div style="margin: 0px; color: rgb(255, 0, 0);"><span
style="white-space: pre;"></span>atorg.mvel.ast.PropertyASTNode.getReducedValueAccelerated(<span
style="text-decoration: underline; color: rgb(0, 0, 128);">PropertyASTNode.java:21</span>)</div>
<div style="margin: 0px; color: rgb(255, 0, 0);"><span
style="white-space: pre;"> </span>at
org.mvel.ast.BinaryOperation.getReducedValueAccelerated(<span
style="text-decoration: underline; color: rgb(0, 0, 128);">BinaryOperation.java:21</span>)</div>
<div style="margin: 0px; color: rgb(255, 0, 0);"><span
style="white-space: pre;"><br>
</span>at org.mvel.MVELRuntime.execute(<span
style="text-decoration: underline; color: rgb(0, 0, 128);">MVELRuntime.java:88</span>)</div>
<div style="margin: 0px; color: rgb(255, 0, 0);"><span
style="white-space: pre;"> </span>at
org.mvel.CompiledExpression.getValue(<span
style="text-decoration: underline; color: rgb(0, 0, 128);">CompiledExpression.java:111</span>)</div>
<div style="margin: 0px; color: rgb(255, 0, 0);"><span
style="white-space: pre;"><br>
</span>atorg.mvel.MVEL.executeExpression(<span
style="text-decoration: underline; color: rgb(0, 0, 128);">MVEL.java:235</span>)</div>
<div style="margin: 0px; color: rgb(255, 0, 0);"><span
style="white-space: pre;"> </span>at
org.drools.base.mvel.MVELPredicateExpression.evaluate(<span
style="text-decoration: underline; color: rgb(0, 0, 128);">MVELPredicateExpression.java:36</span>)</div>
<div style="margin: 0px; color: rgb(255, 0, 0);"><span
style="white-space: pre;"><br>
</span>atorg.drools.rule.PredicateConstraint.isAllowedCachedRight(<span
style="text-decoration: underline; color: rgb(0, 0, 128);">PredicateConstraint.java:240</span>)</div>
<div style="margin: 0px; color: rgb(255, 0, 0);"><span
style="white-space: pre;"> </span>... 13 more</div>
<div style="margin: 0px; color: rgb(0, 0, 128);"><span
style="color: rgb(255, 0, 0);">Caused by: </span><span
style="text-decoration: underline;">java.lang.NullPointerException</span></div>
<div style="margin: 0px; color: rgb(255, 0, 0);"><span
style="white-space: pre;"></span>atsun.reflect.GeneratedMethodAccessor6.invoke
(Unknown Source)</div>
<div style="margin: 0px; color: rgb(255, 0, 0);"><span
style="white-space: pre;"></span>atsun.reflect.DelegatingMethodAccessorImpl.invoke(<span
style="text-decoration: underline; color: rgb(0, 0, 128);">
DelegatingMethodAccessorImpl.java:25</span>)</div>
<div style="margin: 0px; color: rgb(255, 0, 0);"><span
style="white-space: pre;"></span>atjava.lang.reflect.Method.invoke(<span
style="text-decoration: underline; color: rgb(0, 0, 128);">
Method.java:324</span>)</div>
<div style="margin: 0px; color: rgb(255, 0, 0);"><span
style="white-space: pre;"> </span>at
org.mvel.optimizers.impl.refl.GetterAccessor.getValue(<span
style="text-decoration: underline; color: rgb(0, 0, 128);">GetterAccessor.java:42</span>)</div>
<div style="margin: 0px; color: rgb(255, 0, 0);"><span
style="white-space: pre;"><br>
</span>... 22 more</div>
</div>
<div><br>
</div>
<div>Details:</div>
<div> * I use StatelessSessions which are private to the threads</div>
<div> * No data is shared between threads (with the exception of
the RuleBase, as outline above)</div>
<div> * I am on JDK 1.5</div>
<div><br>
</div>
<div>I would be grateful for any pointers for 'correct' use of
Drools in an MT environment.</div>
<div>Cheers,</div>
<div> Ingomar</div>
</div>
<br>
</div>
<div
style="font-size: 8pt; color: rgb(128, 128, 128); line-height: 100%; font-family: Arial,Helvetica,sans-serif;"><span
style="font-weight: bold; font-size: 9pt; color: rgb(0, 0, 0);"><br>
Ingomar Otter</span><br>
<span
style="font-weight: bold; font-size: 9pt; color: rgb(255, 135, 10);">Chief
Technology Officer</span><br>
<a moz-do-not-send="true" href="mailto:ingomar.otter@valtech.de"
target="_blank">ingomar.otter@valtech.de</a><br>
Mobile: +49 172 2367867<br>
<br>
<span
style="font-weight: bold; font-size: 9pt; color: rgb(0, 0, 0);">Valtech
GmbH</span><br>
Bahnstraße 16<br>
40212 Düsseldorf<br>
Germany<br>
<br>
Phone: +49 (0)211 179237-0<br>
Fax: +49 211 179237-19<br>
<br>
<a moz-do-not-send="true" style="color: rgb(128, 128, 128);"
href="http://www.valtech.de/" target="_blank">www.valtech.de</a><br>
<br>
Geschäftsführer: Ingo Kriescher<br>
Amtsgericht Düsseldorf HRB48672</div>
<br>
<div>
</div>
</div>
<br>
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<br>
</blockquote>
</div>
<br>
<br clear="all">
<br>
-- <br>
Fernando Meyer <a moz-do-not-send="true" href="http://fmeyer.org">http://fmeyer.org</a><br>
JBoss Rules Core Developer<br>
<a moz-do-not-send="true" href="mailto:fernando@fmeyer.org">fernando@fmeyer.org</a>
<pre wrap="">
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</blockquote>
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