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From: "sbarriba" <sbarriba@yahoo.co.uk>
To: <users@jackrabbit.apache.org>
References: <0e2f01c8d6ac$876066a0$962133e0$@co.uk>
 <F186AC080E44C146BBE4A33472CFA79F01DB0581@mxs01.tirol.local>
In-Reply-To: <F186AC080E44C146BBE4A33472CFA79F01DB0581@mxs01.tirol.local>
Subject: RE: Locking issues with XAItemStateManager - help appreciated
Date: Wed, 25 Jun 2008 11:35:01 +0100
Message-ID: <0e5a01c8d6af$24127770$6c376650$@co.uk>
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Hi Claus,
Thanks for the quick response.

We're not intentionally using an XA transaction. We're using Spring +
Transaction Manager + Hibernate elsewhere to satisfy the request.

....so a few quick questions:

* Is there a way to force JackRabbit not to use XA? What are the =
alternative
ItemStateManager(s)?
* Does using XA cause more locking?

Thanks in advance,
Regards,
Shaun

-----Original Message-----
From: K=D6LL Claus [mailto:C.KOELL@TIROL.GV.AT]=20
Sent: 25 June 2008 11:24
To: users@jackrabbit.apache.org
Subject: AW: Locking issues with XAItemStateManager - help appreciated

hi,

do you use a xa transaction ?
take a look @ https://issues.apache.org/jira/browse/JCR-1334
i see in your stack that the lock comes from acquireReadLock()
this was also in my issue
feel free do test the PatchedDefaultISMLocking.java by Marcel

BR,
claus

-----Urspr=FCngliche Nachricht-----
Von: sbarriba [mailto:sbarriba@yahoo.co.uk]=20
Gesendet: Mittwoch, 25. Juni 2008 12:16
An: users@jackrabbit.apache.org
Betreff: Locking issues with XAItemStateManager - help appreciated

Hi all,

As follow up to a previous thread we're seeing lots and lots of =
contention
around the following lock. We're using Weblogic 9.1 / JRocket 27.4.0 =
(1.5).

=20

Even with very little load on the app a thread dump shows active threads =
at
exactly this point. As the concurrent load increases the contention
increases until the app is continually thrashing on these locks and =
stops
responding.

=20

Is there a way to configure JackRabbit to reduce the amount of locking?

For example, I note the use of XAItemStateManager in the stack - is =
there an
alternative ItemStateManager implementation which requires less locking?

=20

All help appreciated.

=20

Regards,

Shaun

=20

=20

"[ACTIVE] ExecuteThread: '36' for queue: 'weblogic.kernel.Default
(self-tuning)'" id=3D133 idx=3D0x20c tid=3D6426 prio=3D5 alive, in =
native, daemon

    at =
jrockit/vm/Locks.monitorEnterUnmatched(Ljava/lang/Object;)V(Native
Method)

    at
EDU/oswego/cs/dl/util/concurrent/WriterPreferenceReadWriteLock$ReaderLock=
..ac
quire()V(Unknown Source)

    at
org/apache/jackrabbit/core/state/DefaultISMLocking$ReadLockImpl.<init>(De=
fau
ltISMLocking.java:103)

    at
org/apache/jackrabbit/core/state/DefaultISMLocking$ReadLockImpl.<init>(De=
fau
ltISMLocking.java:97)

    at
org/apache/jackrabbit/core/state/DefaultISMLocking.acquireReadLock(Defaul=
tIS
MLocking.java:65)

    at
org/apache/jackrabbit/core/state/SharedItemStateManager.acquireReadLock(S=
har
edItemStateManager.java:1438)[inlined]

    at
org/apache/jackrabbit/core/state/SharedItemStateManager.getItemState(Shar=
edI
temStateManager.java:237)[optimized]

    at
org/apache/jackrabbit/core/state/LocalItemStateManager.getPropertyState(L=
oca
lItemStateManager.java:118)[inlined]

    at
org/apache/jackrabbit/core/state/LocalItemStateManager.getItemState(Local=
Ite
mStateManager.java:150)[inlined]

    at
org/apache/jackrabbit/core/state/XAItemStateManager.getItemState(XAItemSt=
ate
Manager.java:226)[optimized]

    ^-- Holding lock:
org/apache/jackrabbit/core/state/XAItemStateManager@0x3ea1ae88[thin =
lock]

    at
org/apache/jackrabbit/core/state/SessionItemStateManager.getItemState(Ses=
sio
nItemStateManager.java:175)[optimized]

    at
org/apache/jackrabbit/core/ItemManager.createItemInstance(ItemManager.jav=
a:5
64)[inlined]

    at
org/apache/jackrabbit/core/ItemManager.getItem(ItemManager.java:395)[inli=
ned
]

    at
org/apache/jackrabbit/core/LazyItemIterator.prefetchNext(LazyItemIterator=
..ja
va:90)[inlined]

    at
org/apache/jackrabbit/core/LazyItemIterator.next(LazyItemIterator.java:20=
3)[
optimized]

    ^-- Holding lock: =
org/apache/jackrabbit/core/ItemManager@0x3ea1a4c0[thin
lock]

=20