[rules-users] Reclaiming memory usage
Edson Tirelli
ed.tirelli at gmail.com
Mon Jul 25 20:32:57 EDT 2011
Chris
That defines the expiration policy for ReconfigEvent, but it does not
define the relationship between ReconfigEvent and DataReading. Imagine a
timeline, dotted with ReconfigEvents... what your rule is saying is for each
DataReading event, match it with all the "periods where there is no
ReconfigEvent", as the lifetime of DataReading is infinity.
Maybe a simpler way of understanding it (without using the "not" for
simplification) is think about this:
declare Man
@livesUpTo( 100 years )
end
rule "marriage"
when
$w : Woman( age > 18 )
$m : Man( )
then
// marry woman and man
end
The rule above defines that each woman will merry every existing man,
even if each of them only lives for 100 years.
Edson
2011/7/26 Chris Richmond <crichmond at referentia.com>
> **
> Edson,
>
> I was under the impression that this:
>
>
> declare ReconfigEvent
> @role( event )
> @expires ( 5s )
> end
>
> would cover that, meaning that every ReconfigEvent would expire after 5s,
> thus causing to no longer be needed by the engine.
>
> Thanks,
> Chris
>
>
> On 7/25/2011 12:17 PM, Edson Tirelli wrote:
>
>
> Chris,
>
> I haven't tried your code, but just looking at the rule, there is no
> temporal correlation between DataReading and ReconfigEvent, so if I am not
> mistaken, that will create a required interval of infinite time when the
> temporal reasoning is applied, meaning the engine has to keep the readings
> in memory forever.
>
> Adding a temporal constraint on the ReconfigEvent pattern on your rule
> or defining an explicit expiration policy for the DataReadings are ways to
> work around that.
>
> Edson
>
> 2011/7/26 Chris Richmond <crichmond at referentia.com>
>
>> Hello
>>
>> I am performing a simple test of injecting an event every 1 millisecond
>> like so:
>>
>> for (int x = 0; x < 100000; x++){
>> DataReading dr = new DataReading("Reading " + x, 12.0f);
>> myStream.insert(dr);
>> ksession.fireAllRules();
>> Thread.sleep(1);
>>
>> }
>>
>>
>> The rule that evaluates this is simple. It basically delays "then" for
>> 3s to see if a followup reading is inserted and makes sure that no
>> ReconfigEvent is active(5s expiration).
>>
>> So if a reading comes in and a followup reading is not inserted within 3
>> seconds and there is is not an existing ReconfigEvent event alive, then
>> it should output and insert a ReconfigEvent, essentially disabling any
>> DataReading action on those events for the next 5 seconds or so. This
>> all works just fine as expected.
>>
>> My question is, how come I don't get memory back when all 100,000 of my
>> events have been inserted. Memory goes up slowly over the course of
>> insertions, which I can understand, but once that loop is finished,
>> memory never reduces, so essentially, the application will eventually
>> run out of memory after some time. I should not have to explicitly
>> remove/retract events should I? Shouldn't they be removed from working
>> memory as soon as they are no longer viable? What should I be doing to
>> reclaim memory from the session/knowledgebase?
>>
>> I have included the full Main program here and the Sample.drl file below
>> it.
>>
>> ************FusionMain.java*****************
>>
>> package com.sample;
>>
>> import org.drools.KnowledgeBase;
>> import org.drools.KnowledgeBaseConfiguration;
>> import org.drools.KnowledgeBaseFactory;
>> import org.drools.builder.KnowledgeBuilder;
>> import org.drools.builder.KnowledgeBuilderError;
>> import org.drools.builder.KnowledgeBuilderErrors;
>> import org.drools.builder.KnowledgeBuilderFactory;
>> import org.drools.builder.ResourceType;
>> import org.drools.conf.EventProcessingOption;
>> import org.drools.io.ResourceFactory;
>> import org.drools.logger.KnowledgeRuntimeLogger;
>> import org.drools.logger.KnowledgeRuntimeLoggerFactory;
>> import org.drools.runtime.KnowledgeSessionConfiguration;
>> import org.drools.runtime.StatefulKnowledgeSession;
>> import org.drools.runtime.conf.ClockTypeOption;
>> import org.drools.runtime.rule.WorkingMemoryEntryPoint;
>>
>>
>> public class FusionMain {
>>
>> @SuppressWarnings("restriction")
>> public static void main(String[] args) {
>>
>>
>> try {
>>
>> KnowledgeSessionConfiguration config =
>> KnowledgeBaseFactory.newKnowledgeSessionConfiguration();
>> config.setOption( ClockTypeOption.get("realtime") );
>>
>>
>> KnowledgeBase kbase;
>> kbase = readKnowledgeBase();
>> StatefulKnowledgeSession ksession =
>> kbase.newStatefulKnowledgeSession();
>>
>> WorkingMemoryEntryPoint myStream =
>> ksession.getWorkingMemoryEntryPoint("My Stream");
>>
>> for (int x = 0; x < 100000; x++){
>> DataReading dr = new DataReading("Reading " + x, 12.0f);
>> myStream.insert(dr);
>> ksession.fireAllRules();
>> Thread.sleep(1);
>>
>> }
>>
>> } catch (Exception e) {
>> // TODO Auto-generated catch block
>> e.printStackTrace();
>> }
>>
>> }
>>
>> @SuppressWarnings("restriction")
>> private static KnowledgeBase readKnowledgeBase() throws Exception {
>> KnowledgeBuilder kbuilder =
>> KnowledgeBuilderFactory.newKnowledgeBuilder();
>> kbuilder.add(ResourceFactory.newClassPathResource("Sample.drl"),
>> ResourceType.DRL);
>> KnowledgeBuilderErrors errors = kbuilder.getErrors();
>> if (errors.size() > 0) {
>> for (KnowledgeBuilderError error: errors) {
>> System.err.println(error);
>> }
>> throw new IllegalArgumentException("Could not parse knowledge.");
>> }
>>
>> KnowledgeBaseConfiguration kbConfig =
>> KnowledgeBaseFactory.newKnowledgeBaseConfiguration();
>> kbConfig.setOption( EventProcessingOption.STREAM );
>> KnowledgeBase kbase = KnowledgeBaseFactory.newKnowledgeBase(kbConfig);
>> kbase.addKnowledgePackages(kbuilder.getKnowledgePackages());
>>
>>
>> return kbase;
>> }
>>
>>
>> }
>>
>>
>> *********Sample.drl*************************
>>
>> package com.sample
>>
>>
>> import java.util.Date;
>>
>> declare DataReading
>> @role( event )
>> end
>>
>>
>> declare ReconfigEvent
>> @role( event )
>> @expires ( 5s )
>> end
>>
>>
>>
>> rule "Wait for follup reading or no config"
>> //lock-on-active
>> when
>>
>> $dr: DataReading(reading > 10.0) from entry-point "My Stream"
>> not(DataReading(reading < 10.0, this after[0s,3s] $dr) from
>> entry-point "My Stream")
>> not(ReconfigEvent() from entry-point "My Stream")
>>
>> then
>> System.err.println("Action: " + new Date(System.currentTimeMillis()));
>> System.err.println("Data reading " + $dr.getName() + " > 10");
>> ReconfigEvent rce = new ReconfigEvent();
>> entryPoints["My Stream"].insert( rce );
>>
>> end
>>
>>
>>
>>
>>
>>
>> _______________________________________________
>> rules-users mailing list
>> rules-users at lists.jboss.org
>> https://lists.jboss.org/mailman/listinfo/rules-users
>>
>
>
>
> --
> Edson Tirelli
> JBoss Drools Core Development
> JBoss by Red Hat @ www.jboss.com
>
>
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>
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>
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--
Edson Tirelli
JBoss Drools Core Development
JBoss by Red Hat @ www.jboss.com
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