Hi,
>From the comments on that class:
/// There is meant to be a one-to-one correspondence between a
SessionImpl and /// a PersistentContext.
A SessionImpl is the same as "a session", and sessions are not safe for use
from multiple threads concurrently. So I think the first thing for you to
check is to carefully examine if you might be accessing some session
instance from multiple threads. This can be a bit devious of course...
consider that "accessing an entity" loaded from session A must be regarded
as "accessing session A" (unless the entity have been detached) even if you
might not reference the session directly in that part of the code. So
beware if you are loading entity somewhere are allowing them to linger in
working memory for access from multiple requests/threads.
/Oskar
2017-02-10 11:01 GMT+00:00 <[email protected]>:
> Hi there, I am looking for some general advice, we have 2 web servers
> which frequently (once to twice a day) hit 100% CPU, using process explorer
> I can drill into the W3WP.exe and its associated threads to determine the
> cause, and it appears to be NHibernate when trying to either access or add
> to collections in the 'StatefulPersistenceContext' class. I have provided
> an example stack trace of the process which has been captured directly from
> the web server during high CPU, there are always 2-3 threads with the same
> stack trace:
>
> mscorlib.dll!System.Collections.Generic.Dictionary`2.FindEntry+0x12c
> mscorlib.dll!System.Collections.Generic.Dictionary`2.TryGetValue+0x14
> NHibernate.dll!NHibernate.Engine.StatefulPersistenceContext.
> AddCollection+0x170
> NHibernate.dll!NHibernate.Engine.StatefulPersistenceContext.
> AddUninitializedCollection+0x9e
> NHibernate.dll!NHibernate.Type.CollectionType.GetCollection+0x344
> NHibernate.dll!NHibernate.Type.CollectionType.ResolveKey+0x58
> NHibernate.dll!NHibernate.Type.CollectionType.Assemble+0x12b
> NHibernate.dll!NHibernate.Type.TypeHelper.Assemble+0x2ab
> NHibernate.dll!NHibernate.Cache.Entry.CacheEntry.Assemble+0xae
> NHibernate.dll!NHibernate.Cache.Entry.CacheEntry.Assemble+0x12b
> NHibernate.dll!NHibernate.Event.Default.DefaultLoadEventListener.
> AssembleCacheEntry+0x601
> NHibernate.dll!NHibernate.Event.Default.DefaultLoadEventListener.
> LoadFromSecondLevelCache+0xa30
> NHibernate.dll!NHibernate.Event.Default.DefaultLoadEventListener.
> DoLoad+0x561
> NHibernate.dll!NHibernate.Event.Default.DefaultLoadEventListener.Load+
> 0x3be
> NHibernate.dll!NHibernate.Event.Default.DefaultLoadEventListener.
> ProxyOrLoad+0x267
> NHibernate.dll!NHibernate.Event.Default.DefaultLoadEventListener.
> OnLoad+0x8b4
> NHibernate.dll!NHibernate.Impl.SessionImpl.FireLoad+0x152
> NHibernate.dll!NHibernate.Impl.SessionImpl.InternalLoad+0x155
> NHibernate.dll!NHibernate.Type.EntityType.ResolveIdentifier+0x26a
> NHibernate.dll!NHibernate.Type.ManyToOneType.Assemble+0xff
> NHibernate.dll!NHibernate.Collection.PersistentBag.
> InitializeFromCache+0x16c
> NHibernate.dll!NHibernate.Cache.Entry.CollectionCacheEntry.Assemble+0x66
> NHibernate.dll!NHibernate.Event.Default.DefaultInitializeCollectionEve
> ntListener.InitializeCollectionFromCache+0xa8d
> NHibernate.dll!NHibernate.Event.Default.DefaultInitializeCollectionEve
> ntListener.OnInitializeCollection+0x56f
> NHibernate.dll!NHibernate.Impl.SessionImpl.InitializeCollection+0x18c
> NHibernate.dll!NHibernate.Collection.AbstractPersistentCollection.
> Initialize+0xf9
> NHibernate.dll!NHibernate.Collection.AbstractPersistentCollection.
> Read+0x35
> NHibernate.dll!NHibernate.Collection.Generic.
> PersistentGenericBag`1.System.Collections.Generic.
> IEnumerable<T>.GetEnumerator+0x46
>
> This appears to be a race condition, we are using version 3.3.3.GA. I've
> looked through the source code for a few versions (3.3.3.SP1 and 4.0.0.GA)
> but the code is the same so I am led to believe this could be a
> configuration issue rather than a bug in NHibernate.
>
> Some googling revealed a similar issue posted on S/O and was fixed:
>
> http://stackoverflow.com/questions/26536361/nhibernate-
> enumerating-the-same-collection-on-multiple-threads
>
> Can anyone offer any advice on this at all?
>
>
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