Re: Cayenne commit never modified columns

[Laurent Marchal <lm...@smausa.com>]

Hi,

     Answer to myself : this was a threading issue ! I separated the 
commits in a different context and everything works fine. Don't udpate 
and commit at the same time in a context, as the Cayenne documentation 
state, the ObjectContext is not thread safe so you have to take care of 
synchronization yourself !

Regards,
Laurent.

Le 09/27/2011 10:25 AM, Laurent Marchal a écrit :
> Hi guys,
>
>     I've been successfully used Cayenne for years now, but we have a 
> really weird issue right now : Cayenne is committing columns that are 
> never modified in our code.. I'm pretty sure Cayenne is not the 
> problem, but more the way we use it and I'd like your help on Cayenne 
> internals to discover where it comes from.
>
> In our product we manipulate jobs (tasks), and you can change their 
> statuses (stop/start/restart...etc). For some reason when we commit 
> the status of a job Cayenne randomely updates another one (or more). 
> This is happening quite a lot and we discovered the issue because we 
> have triggers auditing the database. Here's an extract of the audit :
> _Change Date Time_         _UserID_		_DB Table_	_JobName_		_COLUMN_	        	_Before Value_		_After Value
> _
>
> 2010-12-09 08:00:52.700	teixeira	SMASTER_AUX	ARCANO-PUT	Change Reason		(Record Added)		Force Restart :  (Teixeira on 09/12/2010 08:00)
> 2010-12-09 08:00:52.707	teixeira	SMASTER		ARCANO-PUT	Job Status	        Failed			Wait to Start
> 2010-12-09 08:00:52.723	teixeira	SMASTER		NXGLoadPosLe	Job Status	        Finished OK		Job Running
> 2010-12-09 08:00:52.723	teixeira	SMASTER		NXGLoadPosLe	Exit Description	0000000000		Pid = 4456
>
>
> 2011-01-14 19:29:10.763	oper-jla	SMASTER_AUX	LODH-REC-T	Change Reason	        (Record Added)		Skip : RZU (Oper-JLA on 14/01/2011 19:29)
> 2011-01-14 19:29:10.773	oper-jla	SMASTER		G2-RECONSO	Job Status	        Finished OK		Job Running
> 2011-01-14 19:29:10.773	oper-jla	SMASTER		G2-RECONSO	Exit Description	0000000000		Pid = 8968
>
> 2011-01-14 19:29:10.783	oper-jla	SMASTER		LODH-REC-T	Job Status	        Wait Job Dependency	Job to be Skipped
> You can see here that when the job ARCANO-PUT is updated, the job 
> /NXGLoadPosLe /gets updated too. Same for /G2-RECONSO /who gets 
> updated along with LODH-REC-T. You can think that it's a pretty normal 
> behavior (if the objects are modified in the same ObjectContext 
> they'll be commited together) but I'm sure we NEVER modify the column 
> _Exit Description_ ! In the other hand there is a thread that 
> regularly updates those jobs from the database so Cayenne can refresh 
> this _Exit Description_ column.
>
> My guess is that while a refresh is made from the DB and the _Exit 
> Description_ is updated, a commit is made at the same time. Can it 
> cause that issue ? What happens if a thread update/refresh the jobs 
> while another commits on the same ObjectContext ?
>
> Thank you for your help on this.
> Laurent