Hi,
I'm not using caching in that case.
But I'm working with 'child DC'.
I did a test without these 'children DC'. It is now working properly.
The exception OptimisticLockException is properly threw by the Cayenne
framework. So the problem seems to be link with 'child DC'.
-----Original Message-----
From: Michael Gentry [mailto:blacknex..mail.com]
Sent: Wednesday, April 11, 2007 3:03 PM
To: use..ayenne.apache.org
Subject: Re: Optimistic locking
Are you using caching?
http://cayenne.apache.org/doc20/object-caching.html
http://cayenne.apache.org/doc20/configuring-caching-behavior.html
/dev/mrg
On 4/11/07, Marc Gabriel-Willem
<marc.gabriel-wille..ide-international.com>
wrote:
>
> Thank you for your reply.
>
> For information, I'm working on a JSF web application.
> I was doing test using two different browsers (Firefox + IE) in order
to
> avoid session management problem.
>
> Your document describes the optimistic locking as a mechanism that
> detects update done using an external application (SQL+, etc). For
that
> situation, regarding the Cayenne log file, I can tell you it is ok, it
> works.
>
> My concern was the concurrency management in the same Cayenne
> application (for example, 2 users using the same application and
> modifying the same DataObject !).
>
> In that situation, Cayenne does not raise error... Is it normal ?
> Should I use the "snapshot version" data to check if something has
> changed since the beginning of the user modification ?
>
> Thank you
> Marc
>
>
> -----Original Message-----
> From: Michael Gentry [mailto:blacknex..mail.com]
> Sent: Tuesday, April 10, 2007 5:37 PM
> To: use..ayenne.apache.org
> Subject: Re: Optimistic locking
>
> In a lot of web applications (JSP, Struts, Tapestry, ...) the session
is
> usually stored as a cookie in the browser, so opening a new browser
> window
> and re-connecting to the application won't give you a new session and
> therefore you'd be connected to the original session (and DataContext
-- > I'm > assuming you are storing the DC in the session) with the updated values. > Try your test using different concurrent browsers, such as Firefox and > IE/Safari (for example) and see if you get the same results. I use > optimistic locking on pretty much everything and haven't noticed a > problem. > I wrote this a long time ago, too, which may or may not help: > > http://cwiki.apache.org/CAY/optimistic-locking-explained.html > > I'll be out-of-touch for most of the rest of the day, but if you still > have > problems, perhaps someone else on the list can help. > > Thanks, > > /dev/mrg > > > > On 4/10/07, Marc Gabriel-Willem > <marc.gabriel-wille..ide-international.com> > wrote: > > > > Hi, > > > > > > > > I have some trouble with the optimistic locking function. > > > > I set the 'optimistic locking' option to an ObjEntity and moreover I > set > > an attribute as "used for locking". > > > > > > > > I'm in a web environment. > > > > > > > > When I do some modification in a DataObject, the 'log' displayed by > > Cayenne displays properly the query using the attribute for locking > > check. > > > > But, when a concurrent client modifies the 'same' DataObject, no error > > is detected ... because the new value for the optimistic check is > used. > > > > > > > > It is important to note that the DataObject is modified by different > > browser (so different session data context) and by different child > data > > context ! > > > > > > > > Scenario: > > > > > > > > My original record > attr1=MyAttr1, attr2=10:15:10 > > > > My record modified by client #1> attr1=MyAttr2, > > attr2(UseForLock)=10:18:15 [ attrSpecifiedInWhereClause: 10:15:10 ] > > > > My record modified by client #2> attr1=MyAttr3, > > attr2(UseForLock)=10:19:40 [ attrSpecifiedInWhereClause: 10:18:15 ] > > > > > > > > The value of the attribute used for optimistic locking seems to be > > refreshed... > > > > > > > > Thank you, > > > > Marc > > > > > >
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