[rules-users] Rulebase locking

[Joe White]

We have encountered a problem with a lock getting generated on an
AbstractRuleBase and then never released causing new threads to not be
able to execute in that RuleBase. We are on an older version 5.0.1 of
Drools and are working on creating a unit test that we can use to see if
the defect exists in newer releases. That said, any tips that somebody
might have to reproduce a concurrency issue related to rule bases used
across threads would be very helpful. Or if there are other similar JIRA
entries that we can look at that?

 

This occurs only when the system is under relatively high load and there
potentially could be 100 threads attempting to access and use the same
rulebase.

 

This is very similar to this JIRA:

https://issues.jboss.org/browse/JBRULES-2086?page=com.atlassian.jira.plu
gin.system.issuetabpanels:all-tabpanel

 

We have confirmed that we have the fix generated in that ticket.

 

The general related stack traces for the waiting threads is  :

 

java.lang.Thread.State: WAITING

       ...

        at
java.util.concurrent.locks.ReentrantReadWriteLock$ReadLock.lock(Reentran
tReadWriteLock.java:423)

        at
org.drools.common.AbstractRuleBase.readLock(AbstractRuleBase.java:414)

        at
org.drools.common.AbstractWorkingMemory.insert(AbstractWorkingMemory.jav
a:866)

        at
org.drools.common.AbstractWorkingMemory.insert(AbstractWorkingMemory.jav
a:788)

   ...

 

 

   java.lang.Thread.State: BLOCKED on
org.drools.reteoo.ReteooStatefulSession at fec3cf owned by:
DefaultMessageListenerContainer-145

        at
org.drools.common.AbstractWorkingMemory.fireAllRules(AbstractWorkingMemo
ry.java:627)

        at
org.drools.base.FireAllRulesRuleBaseUpdateListener.beforeRuleBaseUnlocke
d(FireAllRulesRuleBaseUpdateListener.java:41)

        at
org.drools.event.RuleBaseEventSupport.fireBeforeRuleBaseUnlocked(RuleBas
eEventSupport.java:123)

        at
org.drools.common.AbstractRuleBase.unlock(AbstractRuleBase.java:408)

        at
org.drools.common.AbstractRuleBase.addPackages(AbstractRuleBase.java:517
)

        at
org.drools.reteoo.ReteooRuleBase.addPackage(ReteooRuleBase.java:388)

        .....

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