topic Re: How to multi instance on sub process in Alfresco Archive

How to multi instance on sub process

nbuso — Wed, 31 Oct 2012 13:08:47 GMT

Hi,I'm trying to obtain concurrent execution of a subprocess, but the behaviour is not what expected; this is how the subprocess is defined: <subProcess id="PerDomainSubProcess" name="PerDomainSubProcess" activiti:async="true"> <multiInstanceLoopCharacteristics isSequential="false"

Re: How to multi instance on sub process

jbarrez — Fri, 02 Nov 2012 08:41:30 GMT

First of all, did you read http://activiti.org/faq.html#WhatIsTheDifferenceBetweenProcessConcurrencyAndJavaConcurrency ?

So yes, your subprocesses will be executed sequentially in the engine.
However, the difference with 'isSequential='true'' is that now all your subprocesses are created at once. In the 'true' case, one subprocess will be created, and when that is finished, the second one will be created.

Re: How to multi instance on sub process

nbuso — Fri, 02 Nov 2012 10:54:24 GMT

thank for the reply.

first of all I'm new to BPM, I'm learning! Than sorry if I'm not completely aware of the subject.

First of all, did you read http://activiti.org/faq.html#WhatIsTheDifferenceBetweenProcessConcurrencyAndJavaConcurrency ?

Yes I read the FAQ before to write the process; but it seem a bit outdated or I didn't read correctly?
It's written "In the future we envision configurations that allow for asynchronous execution of the service methods", what you mean with service methods? are you speaking about tasks in some way?
it's also written " Asynchronous continuations will be introduced to allow for a more fine grained demarcation of transactions for those situations where it is needed"

The User Guide document about this http://activiti.org/userguide/index.html#asyncContinuations. For this reason I'm thinking Activiti is a step forward the FAQ.

So yes, your subprocesses will be executed sequentially in the engine.
However, the difference with 'isSequential='true'' is that now all your subprocesses are created at once. In the 'true' case, one subprocess will be created, and when that is finished, the second one will be created.

Changing a bit the process I obtained something different; I changed the configuration of the first task in the subprocess:


      <scriptTask id="scripttask2" name="simple printout" activiti:async="true" activiti:exclusive="false" scriptFormat="groovy"> …

In this way I'm obtaining some kind of concurrency, is this a correct way to obtain concurrency? but seem to be limited in number of thread used (3). Can this value be changed?
I'm obtaining also some exceptions:


org.activiti.engine.ActivitiOptimisticLockingException: ExecutionEntity[7713] was updated by another transaction concurrently

Explained here http://forums.activiti.org/en/viewtopic.php?f=6&t=4124&p=16187&hilit=ActivitiOptimisticLockingException#p16187

Do you think I can resolve this with the suggestions proposed by ' frederikheremans'?

I will continue reading forums, to me seem other people are interested in concurrency and the User Guide seem not extensively clear on this. I think you should point the reader to "the BPMN" way to manage concurrency, also using external references.

n.

Re: How to multi instance on sub process

jbarrez — Mon, 05 Nov 2012 07:54:59 GMT

In this way I'm obtaining some kind of concurrency, is this a correct way to obtain concurrency? but seem to be limited in number of thread used (3). Can this value be changed?

Yes. In some way. Async continuations are also a way of 'designing' your processes.

You must ask yourself before introducing it: do I really need threading? In most cases, we see that people don't really need threading added to their business processes, and having 'business concurrency' is often way more appropriate (that was actually the section I linked to in the FAQ).

I'm obtaining also some exceptions:

Yes, these are expected when you introduce concurrency.