[rules-users] Query for a fact, and concurrent rule execution

[Michael Anstis]

That's a possibility, but it'd depend on your rules.

As a thought, you could serialise the initialised StatelessKnowledgeSession
into a byte[] (cached at application scope) and deserialise with each
web-service call.

I would wait to see if Mark Proctor, Edson Tirelli or community members
have other thoughts on use of a single StatefulKnowledgeSession.

IIRC it is meant to be thread-safe but think people have reported problems
in the past. Recently:
http://lists.jboss.org/pipermail/rules-dev/2012-February/003857.html

With kind regards,

Mike

On 2 May 2012 11:58, Stephen Lomax <stephen.lomax at mattelli.com> wrote:

> Hi Mike,
>
> Each quote does not enrich the session, we were actively looking to remove
> the quote at the end of the session to prevent it growing as we were just
> comparing the quote to the core product attribute facts.
>
> What is the performance hit in launching a Stateful knowledge session with
> say 10,000 facts, would it make the web service call slow?
>
> Thanks very much for the help on the query also…we will look into that.
>
> Kind Regards
>
> Ste
>
> On 2 May 2012, at 11:31, Michael Anstis wrote:
>
> Does each quote validation exercise enrich the StatefulKnowledgeSession
> with other facts that could influence validation of other quotes?
>
> If not probably using a StatefulKnowledgeSession per HTTP request might be
> more simple (with the KnowledgeBase as an application scoped variable).
>
> Regarding retrieval of results, there are a couple of options that spring
> to mind:-
>
>    - Look at using a Global to collate results.
>    - Look at using a Query (
>    http://stackoverflow.com/questions/5872215/how-do-i-add-facts-to-working-memory-at-runtime-in-the-drools-drl-and-retrieve-t
>    )
>
> With kind regards,
>
> Mike
>
> On 2 May 2012 10:39, stelomax <stephen.lomax at mattelli.com> wrote:
>
>> Hi,
>>
>> Please bear with me, I am relatively new to the world of Drools and have a
>> question.  I am hoping it will be a simple issue.
>>
>> First let me frame my planned implementation at a high level.  I am hoping
>> to use Drools as a real time service enabled quote validation tool.
>>
>> Facts representing products and attributes will be loaded into a stateful
>> knowledge session upon boot (using a piece of Java that loads these as
>> facts
>> from our product DB).
>>
>> The front-end application will allow users to build up quotes consisting
>> of
>> quote lines that make references to these products.  Once the quote is
>> built
>> they will press a "Validate" button.  This will call a webservice that
>> will:
>>
>> 1) Insert the quote details as facts into the knowledge session
>> 2) Run a "rule flow" to validate the quote against the product facts
>> 3) The rules will insert validation results as facts tagged against the
>> quote
>> 4) QUERY for the validation results
>> 5) Retract the facts for the quote (inc validation results)
>> 6) Send the validation results back as a response to the webservice call
>>
>> My first question is how to implement step 4 --> how to physically query
>> for
>> the validation results pertaining to that specific quote.  Any help here
>> would be greatly appreciated.
>>
>> My second question relates to concurrency.  As this is a quote validation
>> tool there will be multiple users validating quotes so we will get
>> concurrent validation requests.
>>
>> What is the recommended manner of dealing with concurrent rule requests
>> within a stateful knowledge session.  If 2 people attempt to validate a
>> different quote at the same time we will have two quotes within the
>> knowledge session together with all of the product facts.  Is drools
>> capable
>> of running two concurrent rule flows against the knowledge session, each
>> referencing a different quote or would we need to instantiate 2 knowledge
>> sessions, or even deal with the matter in a serial manner placing the 2nd
>> quote validation flow on hold until the first completes?
>>
>> Any help/pointers would be great.  I am hoping someone out there has
>> attempted to use Drools in a similar manner :)
>>
>> Many Thanks
>>
>> Ste
>>
>> --
>> View this message in context:
>> http://drools.46999.n3.nabble.com/Query-for-a-fact-and-concurrent-rule-execution-tp3954737.html
>> Sent from the Drools: User forum mailing list archive at Nabble.com.
>> _______________________________________________
>> rules-users mailing list
>> rules-users at lists.jboss.org
>> https://lists.jboss.org/mailman/listinfo/rules-users
>>
>
> _______________________________________________
> rules-users mailing list
> rules-users at lists.jboss.org
> https://lists.jboss.org/mailman/listinfo/rules-users
>
>
>
> _______________________________________________
> rules-users mailing list
> rules-users at lists.jboss.org
> https://lists.jboss.org/mailman/listinfo/rules-users
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.jboss.org/pipermail/rules-users/attachments/20120502/3a2ad42b/attachment.html