*Excellent* description of the system operation and overall and answer to my question.   Thank you very much!

Chris

---

From: rules-users-bounces@lists.jboss.org [mailto:rules-users-bounces@lists.jboss.org] On Behalf Of Edson Tirelli
Sent: Thursday, June 25, 2009 2:28 AM
To: Rules Users List
Subject: Re: [rules-users] Firiing explicit rules

   Chris,

   The decision between A and B must be taken on the basis of: do you need to join objects from the different streams together? If so, you need A. If not, better go with B.

   Regarding threads, the engine works with a single thread, unless you activate the KnowledgeBase partitioning option (check the Drools Fusion documentation), in which case the engine spawns a pool of worker threads. The threads are not assigned to specific streams. They are used as a pool for processing of all required rules in the knowledge base.

   In any case, as long as you don't have multiple threads concurrently inserting facts/events into a single entry-point, everything else is thread safe.

   []s
   Edson

2009/6/24 Chris Richmond <crichmond@referentia.com>

Hello,

For performance reasons, assuming I am using STREAM mode, is it better to :

A. create several streams in my rule file and inject objects into various streams depending on my needs

or

B. create a different session for each stream that I might have had in A. above?

And if I do use option A, is my understanding correct that each stream will be processed on it’s own thread?   

And if so, I notice that I am able to update a common statistical object that I created within my rule file and update it from consequences on different streams.  If each stream is processed on it’s own thread, is updating of this in rule defined statistics object synchronized/thread safe?

For example in my rule file I have the following “stats” object:

# stats object

declare ObjectStats

    id : String @key

    name: String

    lastReadingA : int

    lastReadingB : int

end

….then I have the following two rules……

rule "update stats from objects A”

    lock-on-active

when

    $stats : ObjectStats( $id : id)

    $a : ObjectTypeA(parentId == $id, $aValue : value) from entry-point “stream for objects of type a”

then

    modify($stats) { lastReadingA = $aValue };

end

rule "update stats from objects B”

    lock-on-active

when

    $stats : ObjectStats( $id : id)

    $b : ObjectTypeB(parentId == $id, $bValue : value) from entry-point “stream for objects of type b”

then

    modify($stats) { lastReadingB= $bValue };

end

This is working fine and the lock-on-active seems to be preventing me from getting the “cross product” problem, but is each of these streams processed independantly on their own thread?

Thanks,

Chris

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