Re: [eclipselink-users] dead lock

[James Sutherland <jamesssss@xxxxxxxxx>]

Are you having a deadlock, or just slow performance? 

If you are having a deadlock, please include the full stack of all of the
locked threads (you need at least 2 locked threads with multiple locks to
have a deadlock).

What version are you using?  There have been some cache deadlock fixes, so
please try the latest release.

The easiest workaround to a cache deadlock is to disable the shared cache. 
Another workaround that normally works is to ensure that every relationship
is marked as LAZY, and to avoid JOIN FETCH's.

For a lot of waiting on the connectionPool, this means that you have more
threads than connections in your pool, which is normally not a good idea. 
Either increase the size of your connection pool, or reduce the size of your
application server's thread pool.



ymajoros wrote:
> 
> Hello,
> 
> Regularly, either our connection pool is fully used, or threads are 
> waiting for locks. Is there a locking problem in Eclipselink? We have a 
> big application consisting of about 20 ejb and war modules packaged in 
> an ear.
> 
> I wonder if this is an eclipselink bug there. We only use injected 
> EntityManager (only 99% sure, as there are many developers involved).
> 
> Here is part of the jstack output. Lots of threads with similar trace.
> 
> "httpSSLWorkerThread-443-121" daemon prio=3 tid=0x0000000005b21800 
> nid=0x271ad in Object.wait() [0xfffffd7bc78a3000]
>     java.lang.Thread.State: WAITING (on object monitor)
>          at java.lang.Object.wait(Native Method)
>          - waiting on <0xfffffd7c4ed21e00> (a 
> org.eclipse.persistence.internal.helper.ConcurrencyManager)
>          at java.lang.Object.wait(Object.java:485)
>          at 
> org.eclipse.persistence.internal.helper.ConcurrencyManager.acquire(ConcurrencyManager.java:93)
>          - locked <0xfffffd7c4ed21e00> (a 
> org.eclipse.persistence.internal.helper.ConcurrencyManager)
>          at 
> org.eclipse.persistence.internal.identitymaps.CacheKey.acquire(CacheKey.java:113)
>          at 
> org.eclipse.persistence.internal.identitymaps.AbstractIdentityMap.acquireLock(AbstractIdentityMap.java:107)
>          at 
> org.eclipse.persistence.internal.identitymaps.IdentityMapManager.acquireLock(IdentityMapManager.java:133)
>          at 
> org.eclipse.persistence.internal.sessions.IdentityMapAccessor.acquireLock(IdentityMapAccessor.java:92)
>          at 
> org.eclipse.persistence.internal.sessions.IdentityMapAccessor.acquireLock(IdentityMapAccessor.java:83)
>          at 
> org.eclipse.persistence.internal.descriptors.ObjectBuilder.buildObject(ObjectBuilder.java:692)
> 
> 
> begin:vcard
> fn:Yannick Majoros
> n:Majoros;Yannick
> org:UCL;SGSI/EPC
> adr;quoted-printable:;;place de l'Universit=C3=A9,
> 1;Louvain-la-Neuve;;1348;Belgique
> email;internet:yannick.majoros@xxxxxxxxxxxx
> title;quoted-printable:D=C3=A9veloppeur
> tel;work:+32 10 47.94.42
> tel;cell:+32 498 70.72.13
> x-mozilla-html:TRUE
> version:2.1
> end:vcard
> 
> 
> 


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