[rules-users] Drools & JBPM Persistence

Fri Jun 22 09:00:28 EDT 2012

I see your point, but IMHO that doesn't mean that in certain circumstances,
when the process is being executed in a thread that it is no the same
thread as the one in which drools is executing leads to a situation in
which the persistence mechanisms are not enough to allow a fault tolerant
JBPM for long-time running processes.

As mentioned, there is at least one scenario, at least when mina is
involved, where things are broken.

Alberto R. Galdo
argaldo at gmail.com

On Fri, Jun 22, 2012 at 2:50 PM, Mauricio Salatino <salaboy at gmail.com>wrote:

> I think that you are mixing things up.
> Did you take a look at the CommandBasedStatefulKnowledgeSession?
> Every command that represent an operation against the knowledge session is
> being executed inside a transaction, for both rules and processes. As soon
> as a safe point is found (for both processes and rules) the persistence
> mechanism commits the transaction.
>
> "In fact, this will never dissapear unless some communication mechanism
> between Drools & JBPM is developed to allow the processes to be executed
> inside Drools Reteoo thread."
> Take a look at the class that I mention and then try to explain me what
> you mean with the previous sentence.
>
> Cheers
>
>
> On Fri, Jun 22, 2012 at 9:45 AM, Alberto R. Galdo <argaldo at gmail.com>wrote:
>
>>
>> No, I didn't. I need to be able to deploy the human task server and my
>> knowledge session in separate JVM's. And Mina is on my way.
>>
>> The fact that I am able to do things in some other way doesn't make this
>> very problem dissapear ... :(. In fact, this will never dissapear unless
>> some communication mechanism between Drools & JBPM is developed to allow
>> the processes to be executed  inside Drools Reteoo thread.
>>
>> Isn't that so?
>>
>>
>> Alberto R. Galdo
>> argaldo at gmail.com
>>
>>
>>
>> On Fri, Jun 22, 2012 at 2:17 PM, Mauricio Salatino <salaboy at gmail.com>wrote:
>>
>>> Both persistence mechanisms are already unified.
>>> the jBPM-persistence module extends the Drools one adding the relevant
>>> entities by the processes.
>>>
>>> You can be having problems with the Mina Server, did you try the local
>>> configuration? The Mina Server was designed to run in a different JVM than
>>> the session, as a standalone component, if you are running it in the same
>>> JVM that can be causing some transactional problems as you mention. If you
>>> need to run it in the same JVM you can use the local configuration, did you
>>> try that?
>>> Cheers
>>>
>>> On Fri, Jun 22, 2012 at 8:31 AM, Alberto R. Galdo <argaldo at gmail.com>wrote:
>>>
>>>> Hi,
>>>>
>>>>    I'm opening this thread in the aim of generating a debate about the
>>>> approach to session persistence in Drools and JBPM for BPMN processes which
>>>> by definition are able to generate asynchronous human tasks.
>>>>
>>>>    IMHO the current approach needs to be refactored in favor of joining
>>>> the management of the different Drools and JBPM entities in an unique
>>>> manager.
>>>>
>>>>    The current implementation offers two managers one in Drools, one in
>>>> JBPM. Each of this managers are wrappers of a shared JPA EntityManager
>>>> context and manage their own entities.
>>>>
>>>>    When the integration of JBPM into Drools was done ( leaving behind
>>>> drools flow ), the approach seemed to be to make the entities in JBPM (
>>>> workitems, processinstance and so on ) look like the entities in Drools. As
>>>> a result, the implementation of those entities in JBPM now implement the
>>>> interfaces of the same entities in Drools. That looked like a good
>>>> approach, but the experience, at least mine, seems to reveal it as not that
>>>> good.
>>>>
>>>>    In my opinion, the first problem with that approach is that Drools,
>>>> the reteoo algorithm, runs in a single-threaded environment. Drools
>>>> persistence was designed having this in mind, so for the code in Drools,
>>>> there's no doubt that when in a persistent enviroment, the transaction, if
>>>> any, will be bound to the same thread as the one in which the reteoo
>>>> algorithm is executed. That leads to situations where whenever a class in
>>>> JBPM calls drools in a JBPM's thread ( the mina handler thread, a NIO one
>>>> for instance ), Drools thinks that is being executed in it's own thread (
>>>> where things are expected, as the JTA transaction bound for example ) and
>>>> clearly, in some situations it is not the case. Then Drools expects to find
>>>> certain resources and certain environment which are not always there.
>>>> Leading to failure.
>>>>
>>>>    As Drools now is a dependency for JBPM through the Knowledge-API, I
>>>> think that the management of the persistence for Drools and JBPM should be
>>>> merged in one that makes no assumptions and manages the needs for
>>>> persistence in a coherent way for both products.
>>>>
>>>>    What do you think?
>>>>
>>>>
>>>> "There can be only one" ->
>>>> http://en.wikipedia.org/wiki/Highlander_%28film%29
>>>>
>>>>
>>>> Alberto R. Galdo
>>>> argaldo at gmail.com
>>>>
>>>>
>>>> _______________________________________________
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>>>> https://lists.jboss.org/mailman/listinfo/rules-users
>>>>
>>>>
>>>
>>>
>>> --
>>>  - MyJourney @ http://salaboy.wordpress.com
>>>  - Co-Founder @ http://www.jugargentina.org
>>>  - Co-Founder @ http://www.jbug.com.ar
>>>
>>>  - Salatino "Salaboy" Mauricio -
>>>
>>>
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>>>
>>
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>
>
> --
>  - MyJourney @ http://salaboy.wordpress.com
>  - Co-Founder @ http://www.jugargentina.org
>  - Co-Founder @ http://www.jbug.com.ar
>
>  - Salatino "Salaboy" Mauricio -
>
>
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