[rules-users] Does anyone have a Fusion application running?
I'm asking because I'm continuously getting exceptions from mine. I get exceptions from the engine when it's expiring events, I get exceptions while inserting objects in my rules, I get them when I insert through a named entry point, I get them for the sin of apparently just having a sliding time window in my rules. They're all wrapped around NullPointerExceptions, and while they don't shut the engine down, they ARE preventing the system from working correctly. None of this happens immediately. In the short-term everything appears to be OK. It's after running for 6+ hours that I start to see this. I'm running with 5.2.0-Final, which I know is not the latest release, but I dropped back to it because, well, I was getting too many failures and exceptions with 5.3.0. I'm not inserting data from another thread. The rules engine is started with fireUntilHalt, and when I have a data backlog to insert into it, I call halt and the same thread that called fireUntilHalt loads the data, then calls fireUntilHalt again. I'm not using MultiThreadEvaluationOption -- which in my experience just generates MORE exceptions than I'm getting now. Nothing older than the event expiration age is being inserted. Any advice? Any examples of a continuously-running Fusion application anyone can share with me? Thanks! -- View this message in context: http://drools.46999.n3.nabble.com/Does-anyone-have-a-Fusion-application-running-tp3589002p3589002.html Sent from the Drools: User forum mailing list archive at Nabble.com. ___ rules-users mailing list rules-users@lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users
Re: [rules-users] Rules called with null references?
Another clue: these errors nearly disappear when I change garbage collection settings. I hesitate to say they completely disappear, but in an hour of running I've only seen one exception thrown from inside Drools code, as opposed to many dozens before. The difference is the presence of the options -XX:+UseConcMarkSweepGC -XX:+CMSIncrementalMode. If I run with those, I get activations with null parameters. Without them, I don't. I don't think Drools uses WeakReferences for anything, but I haven't been through all the code. Could something like that be happening? Could the objects be subjected to GC before the activation is created or fires? Oh, I've also added an AgendaListenerEvent that examines the activations for this condition and logs it happening. -- View this message in context: http://drools.46999.n3.nabble.com/Rules-called-with-null-references-tp3477164p3528455.html Sent from the Drools: User forum mailing list archive at Nabble.com. ___ rules-users mailing list rules-users@lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users
Re: [rules-users] Rules called with null references?
I enhanced my ConsequenceExceptionHandler and have a little more detail on
this. I have this rule:
rule Duplicate Alerts
when
$firstAlert : TemperatureAlert( this.saved, this.valid )
$secondAlert : TemperatureAlert (this.location == $firstAlert.location,
this != $firstAlert, this.saved, this.valid )
then
LOG.info(Removing duplicate alert for + $firstAlert.getLocation());
$secondAlert.setValid(false);
$secondAlert.setInvalidAt(new Date());
update($secondAlert);
end
The TemperatureAlert class is not defined as an event.
I'm getting this exception:
15:56:34,145 ERROR [STDERR] CONSEQUENCE EXCEPTION
15:56:34,145 ERROR [STDERR] Exception executing consequence for rule
Duplicate Alerts in xxx.xxx.rules: java.lang.NullPointerException
15:56:34,145 ERROR [STDERR] START FACT DUMP:
15:56:34,145 ERROR [STDERR]
$firstAlert:xxx.xxx.TemperatureAlert@1e3c1689
15:56:34,145 ERROR [STDERR] $secondAlert:null
15:56:34,145 ERROR [STDERR] END FACT DUMP
15:56:34,145 ERROR [STDERR] Exception executing consequence for rule
Duplicate Alerts in xxx.xxx.rules: java.lang.NullPointerException
I don't see how this activation could have ever happened.
If there never was an object that qualified, the activation would never have
been scheduled.
If there was one, but it was updated so it no longer matched or was
retracted, then the activation would have been cancelled.
Everything -- EVERYTHING -- for the session is done within a single thread:
Runnable r = new Runnable() {
public void run() {
while (!shuttingDown) {
try {
session.fireUntilHalt();
while (!commandList.isEmpty()) {
commandList.take().execute();
}
} catch (Throwable t) {
t.printStackTrace();
}
}
}
};
The commandList is a BlockingQueue of objects that, when execute() is
called, variously insert, retract, or update objects. All the data feeding
into the session flows through that queue. The halt() method is called
either when the queue gets too long and periodically if it's not empty.
Any ideas?
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[rules-users] Rules called with null references?
I have this rule: rule Defrost: Turned On when $reading : SwitchReading( switchOn == true ) from entry-point ReadingsStream not SwitchReading (this.circuit == $reading.circuit, this after $reading ) from entry-point ReadingsStream not DefrostSwitchOn(this.circuit == $reading.circuit) then LOG.info(Defrost switch turned on by reading ' + $reading + '.); insert(new DefrostSwitchOn($reading)); end SwitchReading is an event; DefrostSwitchOn is a POJO fact. Multiple times I've gotten exceptions where this rule's RHS is called with a null. The ConsequenceExceptionHandler is supposed to list the facts the RHS was called with, but it's getting an empty list. Now, I know my system as it currently stands can take a LONG time between receiving an event and executing the consequence, primarily when it first starts and is loading its previous known state. It's entirely believable to me that the event will have expired before the rule's RHS is called. But shouldn't the event still be referenced by the Activation? -- View this message in context: http://drools.46999.n3.nabble.com/Rules-called-with-null-references-tp3477164p3477164.html Sent from the Drools: User forum mailing list archive at Nabble.com. ___ rules-users mailing list rules-users@lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users
Re: [rules-users] Help with troubleshooting rules/Drools
I've rolled back to 5.2.0 and it seems to be doing better. Almost an hour of uptime. I already have a custom consequence exception handler -- I think it's cribbed from that link, even. But this exception doesn't appear to happen during the execution of a consequence -- I *think* it's during an event expiration, but I can't swear to that. -- View this message in context: http://drools.46999.n3.nabble.com/Help-with-troubleshooting-rules-Drools-tp3469285p3471173.html Sent from the Drools: User forum mailing list archive at Nabble.com. ___ rules-users mailing list rules-users@lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users
Re: [rules-users] Live Queries and Expired Events
Well, the live query is started *before* any events get inserted, and I have a ViewChangedEventListener registered to listen to that query. I expected to see rowRemoved() called every time an event is expired, but instead only see it happening *MOST* of the time. For example, I have 5000 events inserted. The ViewChangedEventListener updates the corresponding database row as the events expire. I shut off the event feed (so nothing new is going into either the database or the session) and over time the events expire. I can watch the database being updated as the events expire, but then the number flattens out to 50-60 or so that just haven't been touched. As I understand it, expiration happens even if the event matches the conditions for a rule, so they're not being retained for that reason, right? Oh, and when I've had the system down for a while and I'm receiving a backlog of events, they simply seem to disappear on insertion. I haven't traced the path of execution yet, though. -- View this message in context: http://drools.46999.n3.nabble.com/Live-Queries-and-Expired-Events-tp3469198p3471214.html Sent from the Drools: User forum mailing list archive at Nabble.com. ___ rules-users mailing list rules-users@lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users
Re: [rules-users] Live Queries and Expired Events
My terms are likely incorrect, but: - Section 4.3.3.2.2. Live Querries: We have now complimented this with Live Querries, which has a listener attached instead of returning an iterable result set. These live querries stay open creating a view and publish change events for the contents of this view. So now you can execute your query, with parameters and listen to changes in the resulting view. - The listener is not being called for every event, as I'd expect it to be called. -- View this message in context: http://drools.46999.n3.nabble.com/Live-Queries-and-Expired-Events-tp3469198p3471324.html Sent from the Drools: User forum mailing list archive at Nabble.com. ___ rules-users mailing list rules-users@lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users
Re: [rules-users] Help with troubleshooting rules/Drools
They can recalculate just fine -- the underlying AccumulateData is just a SortedSet -- but ISTR there are problems with that code outside of my functions. -- View this message in context: http://drools.46999.n3.nabble.com/Help-with-troubleshooting-rules-Drools-tp3469285p3471330.html Sent from the Drools: User forum mailing list archive at Nabble.com. ___ rules-users mailing list rules-users@lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users
Re: [rules-users] Preventing re-evaluation on modification of 'output' fact
Have you considered making the reasons for being suspicious objects in their own right and inserting them independently? Let's say: SuspectedFraudReason (abstract parent class) TransactionsTooOften (extends SuspectedFraudReason) TransactionsTooHigh (extends SuspectedFraudReason) then indicate the reasons by inserting a new instance of an object, rather than modifying your results object. If you have rules that depend on other indicators of fraud, then they only get evaluated when that particular class of SuspectedFraudReason is inserted, rather than every time you modify the results object. At the end, you can use a query() to collect all the reasons. -- View this message in context: http://drools.46999.n3.nabble.com/Preventing-re-evaluation-on-modification-of-output-fact-tp3455022p3472137.html Sent from the Drools: User forum mailing list archive at Nabble.com. ___ rules-users mailing list rules-users@lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users
[rules-users] Live Queries and Expired Events
I have a live query that should match *all* the events I insert. However, it's apparently not being called for a large number of them. It appears that if an event is expired at the time of insert, it's not tripping the rowRemoved part of the query. Is this the expected behavior? If so, is there some way to catch this condition? Thanks! -- View this message in context: http://drools.46999.n3.nabble.com/Live-Queries-and-Expired-Events-tp3469198p3469198.html Sent from the Drools: User forum mailing list archive at Nabble.com. ___ rules-users mailing list rules-users@lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users
[rules-users] Help with troubleshooting rules/Drools
Any advice on how to troubleshoot problems? I have a fairly simple set of rules (a couple dozen), but keep having problems with fatal exceptions. The most recent was: org.drools.RuntimeDroolsException: Unexpected exception executing action org.drools.reteoo.PropagationQueuingNode$PropagateAction@1e60aa7 at org.drools.common.AbstractWorkingMemory.executeQueuedActions(AbstractWorkingMemory.java:977) at org.drools.common.DefaultAgenda.fireUntilHalt(DefaultAgenda.java:1231) at org.drools.common.AbstractWorkingMemory.fireUntilHalt(AbstractWorkingMemory.java:753) at org.drools.common.AbstractWorkingMemory.fireUntilHalt(AbstractWorkingMemory.java:729) at org.drools.impl.StatefulKnowledgeSessionImpl.fireUntilHalt(StatefulKnowledgeSessionImpl.java:234) at com.kroger.tempmonitor.app.service.RuleService$1.run(RuleService.java:214) at java.lang.Thread.run(Thread.java:662) Caused by: java.util.NoSuchElementException at java.util.LinkedList.remove(LinkedList.java:788) at java.util.LinkedList.removeFirst(LinkedList.java:134) at org.drools.common.PropagationContextImpl.evaluateActionQueue(PropagationContextImpl.java:264) at org.drools.reteoo.PropagationQueuingNode$AssertAction.execute(PropagationQueuingNode.java:357) at org.drools.reteoo.PropagationQueuingNode.propagateActions(PropagationQueuingNode.java:238) at org.drools.reteoo.PropagationQueuingNode$PropagateAction.execute(PropagationQueuingNode.java:502) at org.drools.common.AbstractWorkingMemory.executeQueuedActions(AbstractWorkingMemory.java:975) ... 6 more No mention of a rule name, so where do I begin? My architecture is simple: one thread ran fireUntilHalt(), other (multiple) threads inserting objects. Should I synchronize on the session so only one thread is inserting at a time? There's one rule that triggers a large number of inserts, and it used to give me problems, but I've moved those inserts into Commands and those problems seem to have gone away. Any advice would be welcome, no matter how basic you think it is! Thanks! -- View this message in context: http://drools.46999.n3.nabble.com/Help-with-troubleshooting-rules-Drools-tp3469285p3469285.html Sent from the Drools: User forum mailing list archive at Nabble.com. ___ rules-users mailing list rules-users@lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users
[rules-users] JBRULES-3260: Events forced to zero expirationOffset
It seems like ever since I found this, I can't stop tripping this condition. Basically, while adding the DRL files to the KnowledgeBuilder, ReteooRuleBase decides it has to reconcile event definitions from different packages, so it looks for any that are assignable. At first I thought this was just a guard against having a parent expire quicker than a child class and breaking rules for the child. But now I'm getting this condition for A SINGLE CLASS WITH NO INHERITANCE. At the root of the problem is ReteooRuleBase line 477: node.setExpirationOffset( Math.max( node.getExpirationOffset(), typeDeclaration.getExpirationOffset()+1 ) ); Since neither node nor typeDeclaration have declared expirations, they both have expirationOffset values of -1. The code evaluates: max(-1, -1 + 1) sets the expirationOffset for node to zero, and from then on my objects are expired literally as I insert them. If someone could more clearly state the conditions that trip this code, I'd do my best to avoid them. I've already eliminated inheritance among my events, but that doesn't seem to be enough. -- View this message in context: http://drools.46999.n3.nabble.com/JBRULES-3260-Events-forced-to-zero-expirationOffset-tp3444069p3444069.html Sent from the Drools: User forum mailing list archive at Nabble.com. ___ rules-users mailing list rules-users@lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users
Re: [rules-users] Caching RuleBase in Drools
On Aug 11, 2008, at 9:30 AM, Ingomar Otter wrote: Typically, a rulebase would be generated and cached on first use; to save on the continually re-generation of the Rule Base; which is expensive. Read: Cache the rulebase (the rulebase object) with a Cache mechanism of your choice. AFAIK there is no dedicated caching mechanism in Drools per se. This makes sense, otherwise the next person would look for cache distribution, cache synchronization in a cluster. A can of worms that should not be touched. For example we use JBOSS TreeCache and are happy with it. This may be overkill, simpler implementations like oscache may just be fine - all depends on your requirements and deployment situation. I've just been using a singleton for the moment, tossing it and rebuilding when the rules change. Works OK. ___ rules-users mailing list rules-users@lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users
[rules-users] Parameterized Queries?
Does anyone know how to use parameterized queries? I'm trying to retrieve
ONLY the results for a single installation, with a query like this:
query find errors for site
validationError: ValidationError(this.siteId == $1)
end
QueryResults results = session.getQueryResults(find errors for site, new
Object[] {siteId});
I get the error
org.drools.RuntimeDroolsException: Exception executing predicate
org.drools.base.mvel.MVELPredicateExpression
Caused by: org.mvel.PropertyAccessException: unable to resolve property: $1
I'm pretty sure I'm not writing the rule correctly in the DRL; does anyone
know the correct syntax? The manual isn't clear on this.
Thanks!
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Re: [rules-users] Parameterized Queries?
On Sep 5, 2007, at 2:19 PM, Edson Tirelli wrote: I think Mark just updated documentation for that and it will be included in 4.0.2. Meanwhile: query find errors for site( int $param1, String $param2, ...) validationError: ValidationError( this.siteId == $param1) end Parameter type is optional, and you can have as many parameters as you need. Thanks! That worked perfectly! ___ rules-users mailing list rules-users@lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users
[rules-users] Functionality/Performance Test Results
Our users are asking to be able to specify custom validations in our application. I've been undecided whether to use a rules engine or write our own dynamic validation code. While it's admittedly still in the toy problem stage, I tried using drools in place of some existing hand-coded validation. The drools version took the SAME amount of time. Then I added another rule, to simulate the types of validations our users want to add, and re-ran. Again, SAME time. Admittedly, database access was the big time consumer -- average of 6 seconds per unit of work, and about 15 units of work per test -- but it was the same for both the rules-based and hand-coded validations. Excellent work, everyone! You've made my life much, much simpler! ___ rules-users mailing list rules-users@lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users
