[rules-users] Reclaiming memory usage

[Edson Tirelli]

   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
>
>
>
>
>
>
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>



-- 
  Edson Tirelli
  JBoss Drools Core Development
  JBoss by Red Hat @ www.jboss.com
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