Sorry I can't be of more help. The exception happened to us only once.
I rechecked the log but I don't see anything unusual... the number of
users was high but not abnormal (56 users is high-ish for us). It
happened on a normal SelectQuery with a single matchExp, an ordering and
a fetchLimit, fetching from a simple flat entity -- eight attributes
with no relationships. I suspect it's some intermittent timing/race
thing. Maybe let your JMeter test run for a week?
Andrus Adamchik wrote:
> I did some research of CAY-565 over the weekend. Unfortunately I
> can't reproduce the issue.
>
> I wrote a test case that randomly performs one of the operations -
> select; insert of an object with relationship; object update; object
> delete with relationship. Running up to 30 parallel request threads
> with JMeter, I don't see any exceptions except for occasional fault
> failures (that are expected under these test conditions as I don't
> lock the objects). I even found and fixed an unrelated deadlock that
> I am sure nobody has ever seen in the wild (CAY-573)... still can't
> reproduce the LRUMap problem.
>
> I'll try to change the test conditions, but if Bryan or Lothar (two
> people who have experienced the issue) have any more insights on the
> ways to reproduce it, please share.
>
> Andrus
>
>
> On Jun 16, 2006, at 1:27 PM, Andrus Adamchik wrote:
>
>> On Jun 16, 2006, at 1:12 PM, Lothar Krenzien wrote:
>>
>>> I did it yesterday and now I'm getting the already known NPE again.
>>> And I'm sure that I didn't changed the cayenne version. But what I
>>> saw is that in the case of NPE always the same method of me is called.
>>
>>
>> Very very strange... so this would confirm a suspicion that there is
>> a bug in the LRUMap not related to synchronization.
>>
>>
>>> Another question :
>>> I have a class which is extended from 'WebApplicationListener'. In
>>> the method 'sessionDestroyed' the following code is executed :
>>>
>>> ObjectStore objectStore = dctx.getObjectStore();
>>> objectStore.objectsInvalidated(objectStore.getObjects());
>>>
>>> It that really neccessary ?
>>
>>
>> It may or may not be useful. On the one hand, the ObjectStore is
>> about to go out of scope at this point, so it (and all its objects)
>> will be garbage collected without any extra help.
>>
>> One other thing that invalidate does is throwing away cached
>> snapshots from the cache shared by other sessions. On the positive
>> side it frees up some memory, on the negative - it removes items
>> from cache that could've otherwise speed up object resolution in
>> other sessions.
>>
>> I'd say keep it if your sessions share just a few objects between
>> each other or share no objects at all; throw it away if the object
>> sets significantly overlap between individual sessions.
>>
>> Andrus
>>
>
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