We have multiple threads performing inserts/updates/queries/fireAllRules
and had to synchronize access on working memory.  The performance impact
is surprisingly almost non-existent.

________________________________

From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Anstis, Michael
(M.)
Sent: Monday, July 14, 2008 9:24 AM
To: Rules Dev List
Subject: RE: [rules-dev] Multi threading usage best practice


Hi,
 
Would synchronising on working memory effectively serialise the effects
of fireAllRules()?

        ...
        synchronised(wm) {
            wm.fireAllRules();
        }
        ...

I don't know whether this would kill your through-put either.
 
Cheers,
 
Mike


________________________________

        From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of 9Lives 9Lives
        Sent: 14 July 2008 13:41
        To: [email protected]
        Subject: [rules-dev] Multi threading usage best practice
        
        
        Hello
         
        I'm using Drools 4.0.7 inside a mail relay application 2
determine the operations that need 2 b executed on each passing message.
        To do this i'm using the following scenario:
        

        1.      
                I have a ruleBase.newStatefulSession().
        2.      
                I have a fixed set of facts.
        3.      
                I have a fixed set of rules.
        4.      
                Each mailer (a thread that is handling a single message)
is inserting the message to the working memory, calls the "fireAllRules"
method and retracts the message.
        5.      
                Rules that r executed change custom attributes in the
message.

        Problem:
        I noticed that sometimes a rule can b executed on the same
message more then once.
         
        Assumption:
        My guess is that because i'm working is a multi threading
environment but using a stateful session, what happens is:
        

        1.      Thread A is inserting Message A. 
        2.      Thread B is inserting Message B 
        3.      Thread A is calling fireAllRules 
        4.      Rule X is executed on messages A + B. 
        5.      Thread B is calling fireAllRules 
        6.      Rule X is executed on messages A + B 
        7.      Thread A is retracting Message A 
        8.      Thread B is retracting message B

        Question:
        My goal is 2 make sure a rule is executed only once on a single
message.
        Any ideas on how 2 avoid the situation described above?
         
        TnX
        Dotan
         
         
        
        
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