[rules-dev] Multi threading usage best practice

[9Lives 9Lives]

Opsss. Sorry ... my mistake
 
The phrase: 
"I did use sync on any reference ..." 
should b:
"I did not use sync on any reference ..."Dotan



From: ninelives35 at hotmail.comTo: rules-dev at lists.jboss.orgSubject: RE: [rules-dev] Multi threading usage best practiceDate: Mon, 14 Jul 2008 17:53:59 +0300


I did use sync on any reference 2 the working memory with the hope of archiving the maximum performance from Drools.Stateless session seems like a waste of resources when thinking of the volume of messages passing through the server and translating that 2 create and destroy a session per each one.MayB i should rephrase my rules in some way that they would know if the message was already processed? Dotan



Subject: RE: [rules-dev] Multi threading usage best practiceDate: Mon, 14 Jul 2008 14:51:49 +0100From: manstis1 at ford.comTo: rules-dev at lists.jboss.org


Did you synchronise on the insertion of objects into working memory too? (not as part of an activation on the RHS).
 
What about the use of a stateless session per thread (isn't session creation really quick once the package\rulebase has been compiled)? In the mail relay below won't you want the set of rules to apply to one set of facts inserted by one thread representing one message? Is this achievable with a shared working memory? (Could you not get an activation caused by the presence of a fact inserted into working memory by one thread and the insertion into the same working memory of a fact by another thread).
 
This is much more interesting that work ;-)
 
Mike




From: rules-dev-bounces at lists.jboss.org [mailto:rules-dev-bounces at lists.jboss.org] On Behalf Of Fenderbosch, EricSent: 14 July 2008 14:36To: Rules Dev ListSubject: RE: [rules-dev] Multi threading usage best practice

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: rules-dev-bounces at lists.jboss.org [mailto:rules-dev-bounces at lists.jboss.org] On Behalf Of Anstis, Michael (M.)Sent: Monday, July 14, 2008 9:24 AMTo: Rules Dev ListSubject: 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: rules-dev-bounces at lists.jboss.org [mailto:rules-dev-bounces at lists.jboss.org] On Behalf Of 9Lives 9LivesSent: 14 July 2008 13:41To: rules-dev at lists.jboss.orgSubject: [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:


I have a ruleBase.newStatefulSession().

I have a fixed set of facts.

I have a fixed set of rules.

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.

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:

Thread A is inserting Message A. 
Thread B is inserting Message B 
Thread A is calling fireAllRules 
Rule X is executed on messages A + B. 
Thread B is calling fireAllRules 
Rule X is executed on messages A + B 
Thread A is retracting Message A 
Thread B is retracting message BQuestion: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? TnXDotan  

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