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<DIV><html><body style="word-wrap: break-word; -webkit-nbsp-mode:
space; -webkit-line-break: after-white-space; ">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-top: 0px;
margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal
normal normal 11px/normal Monaco; min-height: 15px; "><br></div><div
style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px;
margin-left: 0px; font: normal normal normal 11px/normal Monaco; color:
rgb(255, 0, 0); "><span style="text-decoration: underline ; color:
#000080">org.drools.RuntimeDroolsException</span>: Exception executing
predicate org.drools.base.mvel.MVELPredicateExpression@bb981e</div><div
style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px;
margin-left: 0px; font: normal normal normal 11px/normal Monaco; color:
rgb(255, 0, 0); "><span class="Apple-tab-span" style="white-space:pre"></span>atorg.drools.rule.PredicateConstraint.isAllowedCachedRight(<span
style="text-decoration: underline ; color:
#000080">PredicateConstraint.java:246</span>)</div><div style="margin-top:
0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal
normal normal 11px/normal Monaco; color: rgb(255, 0, 0); "><span
class="Apple-tab-span" style="white-space:pre"> </span>at
org.drools.common.TripleBetaConstraints.isAllowedCachedRight(<span
style="text-decoration: underline ; color:
#000080">TripleBetaConstraints.java:200</span>)</div><div
style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px;
margin-left: 0px; font: normal normal normal 11px/normal Monaco; color:
rgb(255, 0, 0); "><span class="Apple-tab-span" style="white-space:pre"></span>atorg.drools.reteoo.JoinNode.assertObject(<span style="text-decoration:
underline ; color: #000080">JoinNode.java:150</span>)</div><div
style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px;
margin-left: 0px; font: normal normal normal 11px/normal Monaco; color:
rgb(255, 0, 0); "><span class="Apple-tab-span" style="white-space:pre"></span>atorg.drools.reteoo.CompositeObjectSinkAdapter.propagateAssertObject(<span
style="text-decoration: underline ; color:
#000080">CompositeObjectSinkAdapter.java:318</span>)</div><div
style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px;
margin-left: 0px; font: normal normal normal 11px/normal Monaco; color:
rgb(255, 0, 0); "><span class="Apple-tab-span" style="white-space:pre"></span>atorg.drools.reteoo.ObjectTypeNode.assertObject(<span
style="text-decoration: underline ; color:
#000080">ObjectTypeNode.java:153</span>)</div><div style="margin-top: 0px;
margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal
normal normal 11px/normal Monaco; color: rgb(255, 0, 0); "><span
class="Apple-tab-span" style="white-space:pre"> </span>at
org.drools.reteoo.Rete.assertObject(<span style="text-decoration:
underline ; color: #000080">Rete.java:175</span>)</div><div
style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px;
margin-left: 0px; font: normal normal normal 11px/normal Monaco; color:
rgb(255, 0, 0); "><span class="Apple-tab-span" style="white-space:pre"></span>atorg.drools.reteoo.ReteooRuleBase.assertObject(<span
style="text-decoration: underline ; color:
#000080">ReteooRuleBase.java:192</span>)</div><div style="margin-top: 0px;
margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal
normal normal 11px/normal Monaco; color: rgb(255, 0, 0); "><span
class="Apple-tab-span" style="white-space:pre"> </span>at
org.drools.reteoo.ReteooWorkingMemory.doInsert(<span
style="text-decoration: underline ; color:
#000080">ReteooWorkingMemory.java:71</span>)</div><div style="margin-top:
0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal
normal normal 11px/normal Monaco; color: rgb(255, 0, 0); "><span
class="Apple-tab-span" style="white-space:pre"> </span>at
org.drools.common.AbstractWorkingMemory.insert(<span
style="text-decoration: underline ; color:
#000080">AbstractWorkingMemory.java:909</span>)</div><div
style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px;
margin-left: 0px; font: normal normal normal 11px/normal Monaco; color:
rgb(255, 0, 0); "><span class="Apple-tab-span" style="white-space:pre"></span>atorg.drools.common.AbstractWorkingMemory.insert(<span
style="text-decoration: underline ; color:
#000080">AbstractWorkingMemory.java:881</span>)</div><div
style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px;
margin-left: 0px; font: normal normal normal 11px/normal Monaco; color:
rgb(255, 0, 0); "><span class="Apple-tab-span" style="white-space:pre"></span>atorg.drools.common.AbstractWorkingMemory.insert(<span
style="text-decoration: underline ; color:
#000080">AbstractWorkingMemory.java:682</span>)</div><div
style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px;
margin-left: 0px; font: normal normal normal 11px/normal Monaco; color:
rgb(255, 0, 0); "><span class="Apple-tab-span" style="white-space:pre"></span>atxxxx.DroolsPD.validate(<span style="text-decoration: underline ; color:
#000080">DroolsPD.java:66</span>)</div><div style="margin-top: 0px;
margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal
normal normal 11px/normal Monaco; color: rgb(255, 0, 0); "><span
class="Apple-tab-span" style="white-space:pre"> </span>at
xxxx.DroolsMTRunner.run(<span style="text-decoration: underline ; color:
#000080">DroolsMTRunner.java:30</span>)</div><div style="margin-top: 0px;
margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal
normal normal 11px/normal Monaco; color: rgb(255, 0, 0); "><span
class="Apple-tab-span" style="white-space:pre"> </span>at
java.lang.Thread.run(<span style="text-decoration: underline ; color:
#000080">Thread.java:552</span>)</div><div style="margin-top: 0px;
margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal
normal normal 11px/normal Monaco; color: rgb(255, 0, 0); ">Caused by:
<span style="text-decoration: underline ; color:
#000080">org.mvel.CompileException</span>: cannot invoke getter:
getSAClass [declr.class: xxx.AbstractSA; act.class: null]</div><div
style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px;
margin-left: 0px; font: normal normal normal 11px/normal Monaco; color:
rgb(255, 0, 0); "><span class="Apple-tab-span" style="white-space:pre"></span>atorg.mvel.optimizers.impl.refl.GetterAccessor.getValue(<span
style="text-decoration: underline ; color:
#000080">GetterAccessor.java:52</span>)</div><div style="margin-top: 0px;
margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal
normal normal 11px/normal Monaco; color: rgb(255, 0, 0); "><span
class="Apple-tab-span" style="white-space:pre"> </span>at
org.mvel.optimizers.impl.refl.VariableAccessor.getValue(<span
style="text-decoration: underline ; color:
#000080">VariableAccessor.java:39</span>)</div><div style="margin-top:
0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal
normal normal 11px/normal Monaco; color: rgb(255, 0, 0); "><span
class="Apple-tab-span" style="white-space:pre"> </span>at
org.mvel.ast.VariableDeepPropertyNode.getReducedValueAccelerated(<span
style="text-decoration: underline ; color:
#000080">VariableDeepPropertyNode.java:22</span>)</div><div
style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px;
margin-left: 0px; font: normal normal normal 11px/normal Monaco; color:
rgb(255, 0, 0); "><span class="Apple-tab-span" style="white-space:pre"></span>atorg.mvel.ast.PropertyASTNode.getReducedValueAccelerated(<span
style="text-decoration: underline ; color:
#000080">PropertyASTNode.java:21</span>)</div><div style="margin-top: 0px;
margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal
normal normal 11px/normal Monaco; color: rgb(255, 0, 0); "><span
class="Apple-tab-span" style="white-space:pre"> </span>at
org.mvel.ast.BinaryOperation.getReducedValueAccelerated(<span
style="text-decoration: underline ; color:
#000080">BinaryOperation.java:21</span>)</div><div style="margin-top: 0px;
margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal
normal normal 11px/normal Monaco; color: rgb(255, 0, 0); "><span
class="Apple-tab-span" style="white-space:pre"> </span>at
org.mvel.MVELRuntime.execute(<span style="text-decoration: underline ;
color: #000080">MVELRuntime.java:88</span>)</div><div style="margin-top:
0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal
normal normal 11px/normal Monaco; color: rgb(255, 0, 0); "><span
class="Apple-tab-span" style="white-space:pre"> </span>at
org.mvel.CompiledExpression.getValue(<span style="text-decoration:
underline ; color: #000080">CompiledExpression.java:111</span>)</div><div
style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px;
margin-left: 0px; font: normal normal normal 11px/normal Monaco; color:
rgb(255, 0, 0); "><span class="Apple-tab-span" style="white-space:pre"></span>atorg.mvel.MVEL.executeExpression(<span style="text-decoration: underline ;
color: #000080">MVEL.java:235</span>)</div><div style="margin-top: 0px;
margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal
normal normal 11px/normal Monaco; color: rgb(255, 0, 0); "><span
class="Apple-tab-span" style="white-space:pre"> </span>at
org.drools.base.mvel.MVELPredicateExpression.evaluate(<span
style="text-decoration: underline ; color:
#000080">MVELPredicateExpression.java:36</span>)</div><div
style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px;
margin-left: 0px; font: normal normal normal 11px/normal Monaco; color:
rgb(255, 0, 0); "><span class="Apple-tab-span" style="white-space:pre"></span>atorg.drools.rule.PredicateConstraint.isAllowedCachedRight(<span
style="text-decoration: underline ; color:
#000080">PredicateConstraint.java:240</span>)</div><div style="margin-top:
0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal
normal normal 11px/normal Monaco; color: rgb(255, 0, 0); "><span
class="Apple-tab-span" style="white-space:pre"> </span>... 13
more</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom:
0px; margin-left: 0px; font: normal normal normal 11px/normal Monaco;
color: rgb(0, 0, 128); "><span style="color: #ff0000">Caused by:
</span><span style="text-decoration:
underline">java.lang.NullPointerException</span></div><div
style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px;
margin-left: 0px; font: normal normal normal 11px/normal Monaco; color:
rgb(255, 0, 0); "><span class="Apple-tab-span" style="white-space:pre"></span>atsun.reflect.GeneratedMethodAccessor6.invoke(Unknown Source)</div><div
style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px;
margin-left: 0px; font: normal normal normal 11px/normal Monaco; color:
rgb(255, 0, 0); "><span class="Apple-tab-span" style="white-space:pre"></span>atsun.reflect.DelegatingMethodAccessorImpl.invoke(<span
style="text-decoration: underline ; color:
#000080">DelegatingMethodAccessorImpl.java:25</span>)</div><div
style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px;
margin-left: 0px; font: normal normal normal 11px/normal Monaco; color:
rgb(255, 0, 0); "><span class="Apple-tab-span" style="white-space:pre"></span>atjava.lang.reflect.Method.invoke(<span style="text-decoration: underline ;
color: #000080">Method.java:324</span>)</div><div style="margin-top: 0px;
margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal
normal normal 11px/normal Monaco; color: rgb(255, 0, 0); "><span
class="Apple-tab-span" style="white-space:pre"> </span>at
org.mvel.optimizers.impl.refl.GetterAccessor.getValue(<span
style="text-decoration: underline ; color:
#000080">GetterAccessor.java:42</span>)</div><div style="margin-top: 0px;
margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal
normal normal 11px/normal Monaco; color: rgb(255, 0, 0); "><span
class="Apple-tab-span" style="white-space:pre"> </span>... 22
more</div></div><div><br
class="webkit-block-placeholder"></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
class="webkit-block-placeholder"></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></body></html><BR></DIV>
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