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From "Kevin Sutter (JIRA)" <j...@apache.org>
Subject [jira] Commented: (OPENJPA-115) Bottleneck(s) with using OpenJPA in a Container-managed environment
Date Thu, 01 Feb 2007 22:22:05 GMT

    [ https://issues.apache.org/jira/browse/OPENJPA-115?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#action_12469598
] 

Kevin Sutter commented on OPENJPA-115:
--------------------------------------

I'm going to go ahead with the proposed changes to remove the explicit lock/unlock invocations,
and change the _brokers definition to use ConcurrentReferenceHashSet with weak references.
 The problem at shutdown was with the EMF.close processing.  It is attempting to close any
outstanding EM's that had not been closed.  But, as it was iterating through this list, one
of the EM instances became null and caused an NPE.  Not sure if this is due to the weak references
being GC'd or it indicates a possible problem with the underlying Collections MapBackedSet
or something else, but a simple null check gets around this problem.

With these changes, the initial bottleneck with running OpenJPA in a server environment has
been resolved.  We are still pursuing other performance concerns, but we'll open new JIRA
reports when we get something more concrete.

Kevin

> Bottleneck(s) with using OpenJPA in a Container-managed environment
> -------------------------------------------------------------------
>
>                 Key: OPENJPA-115
>                 URL: https://issues.apache.org/jira/browse/OPENJPA-115
>             Project: OpenJPA
>          Issue Type: Bug
>          Components: kernel
>            Reporter: Kevin Sutter
>         Assigned To: Kevin Sutter
>            Priority: Critical
>
> Running some benchmarks against OpenJPA using the Sun Java System (SunOne) application
server.  Under load, we're not able to push the cpu to 100%.  The culprit seems to be the
lock and synchronization processing within AbstractBrokerFactory.newBroker(..).  According
to sections 5.9.1 and 5.9.2 in the JPA specification, it looks like OpenJPA is attempting
to do too much management of the created EntityManagers.  Within a Container-managed environment,
the Container takes care of the lifecycle of the EntityManagers.  So, there does not seem
to be a need to do the findBroker(..) invocation, nor is there a need to keep track of the
created EntityManagers (_brokers) so that they can be closed when the Factory is closed.
> Once we have verified these changes, there may be others that are needed.  But, we have
to get by this bottleneck first before going to the next layer...
> Kevin

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