[jboss-jira] [JBoss JIRA] Commented: (JBPM-1071) Possible problem in concurrent signalling from multiple threads

[Koen Aers (JIRA)]

    [ http://jira.jboss.com/jira/browse/JBPM-1071?page=comments#action_12388692 ] 
            
Koen Aers commented on JBPM-1071:
---------------------------------

I have been able to reproduce the issue for MySQL (not for HSQLDB) on my T60 Dual Core. So it looks like it only happens in the case of 'true' concurrency on a multi processor system as Len pointed out. I'll investigate some more to track down the possible causes and/or fixes

> Possible problem in concurrent signalling from multiple threads
> ---------------------------------------------------------------
>
>                 Key: JBPM-1071
>                 URL: http://jira.jboss.com/jira/browse/JBPM-1071
>             Project: JBoss jBPM
>          Issue Type: Bug
>          Components: Core Engine
>    Affects Versions: jBPM jPDL 3.2.2
>         Environment: Linux  2.6.21-1.3228.fc7 #1 SMP Tue Jun 12 14:56:37 EDT 2007 x86_64 x86_64 x86_64 GNU/Linux
> MySQL 5.0.22
>            Reporter: Jiri Pechanec
>         Assigned To: Tom Baeyens
>            Priority: Critical
>         Attachments: expl.tar.gz, LockingTest.java
>
>
> Attached is a simple test case that
> 1) Deploys process definition with two nodes
> 2) Starts the process instance that will go to the wait state on first node
> 3) Starts 20 threads that tries concurrently signal the same process instance
> 4) The second node writes a record to the database
> The test case needs to be executed multiple times to see the incorrect behaviour.
> This is an example of run output
> Isol 8
> Action 1
> Action 2
> Action 2
> Action 2
> Action 2
> Action 2 1
> Action 2 1
> Action 2 1
> Action 2 1
> Signalist 5
> Signalist 6
> Signalist 8
> Signalist 12
> Signalist 7
> Signalist 13
> Signalist 14
> Signalist 15
> Signalist 9
> Signalist 16
> Signalist 17
> Signalist 18
> Signalist 4
> Success 7
> Failure 13
> Explanation of the outcome
> 4 threads successfully executed the node action including database operation. All database opeartion were comitted (4 new records were created)
> 3 threads successfully executed the signal operation but no real action was performed
> 13 threads attempted to execute the signal operation but ended with an exception

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