On May 29, 2009, at 2:25 PM, Timo Hoepfner wrote:
Thanks for your help Chuck,
Been there...
Glad to hear I'm not dreaming this.
Oh, it gets worse. Schroedinger's Cat. Logging out some debug
information (currentSnapshot and committedSnapshot come to mind) can
make the problem go away! Of course, once you are satisfied that you
have fixed the problem and remove the debug statements, it comes back.
I have seen this in these cases:
1. Use of unlocked editing context
see below
2. Use of mutable attributes
I'm 100% certain this is not the case.
3. Faults firing during saveChanges (while processing deletes in
particular)
Everything happens in one EC. The order shouldn't be a fault at this
point,
It does not need to be the order. It can be any object that is
touched during the save process.
as the order was created and saved in it already. But nevertheless,
my stomack says, this is the route to follow. I keep the session
alife indefinitely using ERXJSLifebeat, and I'm under the impression
the problem happens more often after either app-startup or a long
period of idle time. Maybe something getting garbage collected/
invalidated after a while?
That is possible, but I have no recollection of running into these
sorts of problems. It is certainly something to be suspicious of.
Is there any chance that autolocking is turned off for ERXEC?
I'm pretty sure it's not, but I'll add more checks. The annoying
part of the problem is, that it's so hard to reproduce.
Which means that it is caused by concurrency.
I've setup Selenium tests, creating 100 orders each, but none of the
tests exhibits the problem.
You need to run these in parallel, preferrably on more than one
machine and also reproduce the other system activity.
In production I get around 10 "bad orders" a day, while 50-300
orders work fine. This morning I could immedeately reproduce the
problem 2 times in a row and already felt on the winning road, but
after that, it took hors to get the next failure...
That is pretty much par for the course. Thinking about this some
more, I think this is what is happening:
1. Order is changed
2. EC records snapshot and adds object to updated list
3. Notification is received, updated list is discarded (along with
inserted and deleted)
4. saveChanges is called, and seeing nothing in the updated list, does
nothing.
Thanks for your help. I owe you some gallons of beer at WOWODC. :)
No need, but you can help me drink some. :-)
Chuck
--
Chuck Hill Senior Consultant / VP Development
Come to WOWODC'09 in San Fran this June!
http://www.wocommunity.org/wowodc09/
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