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Greg, thanks for the tip. I wasn't aware of jconsole. I grew up on
'C' and am still finding my way around java and its tools.<br>
<br>
I recreated the situation and both jconsole and netbeans (running under
its debugger) report "No deadlock detected". Yet here I am with three
threads in the middle of api calls to drools and nothing moving. Sar
says 98-100% idle, so I don't think I put into a spin loop of some
sort. While paused, I added breakpoints to the next line after the
various calls into drools just to make sure I wasn't repeatedly calling
the same thing. No hits.<br>
<br>
This round I again have the same three scenarios:<br>
- fireAllRules<br>
- insert<br>
- add package<br>
<br>
cb<br>
<br>
<br>
<br>
Greg Barton wrote:
<blockquote cite="mid:35825.75558.qm@web81501.mail.mud.yahoo.com"
type="cite">
<pre wrap="">Did you do deadlock detection in a tool like jconsole?
--- On Thu, 8/6/09, Charles Binford <a class="moz-txt-link-rfc2396E" href="mailto:Charles.Binford@sun.com"><Charles.Binford@sun.com></a> wrote:
</pre>
<blockquote type="cite">
<pre wrap="">From: Charles Binford <a class="moz-txt-link-rfc2396E" href="mailto:Charles.Binford@sun.com"><Charles.Binford@sun.com></a>
Subject: [rules-users] multi-threaded deadlock?
To: "Rules Users List" <a class="moz-txt-link-rfc2396E" href="mailto:rules-users@lists.jboss.org"><rules-users@lists.jboss.org></a>
Date: Thursday, August 6, 2009, 4:08 PM
All,
Drools 4.0.7.
I have a single rulebase and three threads running
stateless sessions
(each thread has it's own session). All appears to
work fine until I
try to dynamically update the packages in the
rulebase. That scenario
intermittently hangs on an apparent deadlock. The
documentation says,
"Packages can be added and removed at any time...", but
maybe this
wasn't assuming a multi-threaded context?
The stack trace of my three threads is below.
- Thread 10 is in the middle if fireAllRules
- Thread 12 is trying to add facts to its session
- thread 11 is trying to add a new package to the ruleBase,
but seems to
be in some flavor of fireAllRules on the ruleBase even
though there is
no session argument in this code path.
Am I breaking some fundamental drools rule for
multi-threading? Do I
need to lock out other sessions from activity while
updating packages?
Thanks
Charles Binford
"Thread-10"
java.lang.Object.wait(Object.java)
java.lang.Object.wait(Object.java:485)
org.drools.util.concurrent.locks.ReentrantLock$NonfairSync.lock(ReentrantLock.java:106)
org.drools.util.concurrent.locks.ReentrantLock.lock(ReentrantLock.java:195)
org.drools.common.AbstractWorkingMemory.getFactHandleByIdentity(AbstractWorkingMemory.java:604)
org.drools.base.DefaultKnowledgeHelper.update(DefaultKnowledgeHelper.java:98)
com.sun.evtl.pe.customerPolicy.adm.rules.Rule_turn_on_batch_0.consequence(Rule_turn_on_batch_0.java:8)
com.sun.evtl.pe.customerPolicy.adm.rules.Rule_turn_on_batch_0ConsequenceInvoker.evaluate(Rule_turn_on_batch_0ConsequenceInvoker.java:22)
org.drools.common.DefaultAgenda.fireActivation(DefaultAgenda.java:554)
org.drools.common.DefaultAgenda.fireNextItem(DefaultAgenda.java:518)
org.drools.common.AbstractWorkingMemory.fireAllRules(AbstractWorkingMemory.java:475)
org.drools.common.AbstractWorkingMemory.fireAllRules(AbstractWorkingMemory.java:439)
com.sun.evtl.pe.common.PolicyManager.fireRules(PolicyManager.java:353)
com.sun.evtl.pe.customerPolicy.adm.rules.ArchiveMgrThrd.fireRules(ArchiveMgrThrd.java:132)
com.sun.evtl.pe.customerPolicy.adm.rules.ArchiveMgrThrd.runEngine(ArchiveMgrThrd.java:51)
com.sun.evtl.pe.customerPolicy.adm.msg.PolicyListenerThrd.run(PolicyListenerThrd.java:57)
java.lang.Thread.run(Thread.java:619)
"Thread-11"
org.drools.common.AbstractWorkingMemory.fireAllRules(AbstractWorkingMemory.java:439)
org.drools.base.FireAllRulesRuleBaseUpdateListener.beforeRuleBaseUnlocked(FireAllRulesRuleBaseUpdateListener.java:29)
org.drools.event.RuleBaseEventSupport.fireBeforeRuleBaseUnlocked(RuleBaseEventSupport.java:168)
org.drools.common.AbstractRuleBase.unlock(AbstractRuleBase.java:361)
org.drools.common.AbstractRuleBase.addPackage(AbstractRuleBase.java:456)
com.sun.evtl.pe.common.PolicyManager.addPackage(PolicyManager.java:237)
com.sun.evtl.pe.customerPolicy.adm.rules.ArchiveMgr.loadNewUserRules(ArchiveMgr.java:170)
com.sun.evtl.pe.customerPolicy.adm.msg.PolicyListenerThrd.run(PolicyListenerThrd.java:78)
java.lang.Thread.run(Thread.java:619)
"Thread-12"
java.lang.Object.wait(Object.java)
java.lang.Object.wait(Object.java:485)
org.drools.util.concurrent.locks.ReentrantLock$NonfairSync.lock(ReentrantLock.java:106)
org.drools.util.concurrent.locks.ReentrantLock.lock(ReentrantLock.java:195)
org.drools.common.AbstractWorkingMemory.insert(AbstractWorkingMemory.java:743)
org.drools.common.AbstractWorkingMemory.insert(AbstractWorkingMemory.java:704)
com.sun.evtl.pe.common.PolicyManager.insertSensor(PolicyManager.java:316)
com.sun.evtl.pe.customerPolicy.adm.rules.ArchiveMgrThrd.assertFacts(ArchiveMgrThrd.java:79)
com.sun.evtl.pe.customerPolicy.adm.rules.ArchiveMgrThrd.runEngine(ArchiveMgrThrd.java:50)
com.sun.evtl.pe.customerPolicy.adm.msg.PolicyListenerThrd.run(PolicyListenerThrd.java:57)
java.lang.Thread.run(Thread.java:619)
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<pre wrap=""><!---->
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