You are viewing a plain text version of this content. The canonical link for it is here.
Posted to commits@cayenne.apache.org by "Donald Vrakking (JIRA)" <ji...@apache.org> on 2010/09/29 17:26:33 UTC
[jira] Created: (CAY-1487) Access to ObjectStore.objectMap not
thread safe when creating new object instance (and processing snaphot
events)
Access to ObjectStore.objectMap not thread safe when creating new object instance (and processing snaphot events)
-----------------------------------------------------------------------------------------------------------------
Key: CAY-1487
URL: https://issues.apache.org/jira/browse/CAY-1487
Project: Cayenne
Issue Type: Bug
Components: Core Library
Affects Versions: 2.0 branch
Reporter: Donald Vrakking
The method ObjectStore.registerNode(..) is not synchronized, while getNode(..) is. The objectMap can be accessed in a thread-unsafe way when a new object instance is created and when at the same time snapshotevents are processed.
When creating the instance, the unsafe registerNode method is used. It will start looping in the objectMap when at the same time when an EventDispatch thread tries to acces the objectMap through getNode(). The dispatch threads will go in a WAIT state which eventually results in a completely frozen application.
I noticed that in cayenne 3 the registerNode() method is synchronized. Can such a fix also be applied to a cayenne 2.0.5 release?
--
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.
[jira] Commented: (CAY-1487) Access to ObjectStore.objectMap not
thread safe when creating new object instance (and processing snaphot
events)
Posted by "Andrus Adamchik (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/CAY-1487?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12922050#action_12922050 ]
Andrus Adamchik commented on CAY-1487:
--------------------------------------
> The most obvious question; do you have an indication on when you have a fix ready? ;-)
Not yet.
> Or is there something we can try? In cayenne 3 the method ObjectStore.registerNode is synchronized. Is that all that need to be done or are there other considerations?
Can you upgrade to 3.0.1?
> Access to ObjectStore.objectMap not thread safe when creating new object instance (and processing snaphot events)
> -----------------------------------------------------------------------------------------------------------------
>
> Key: CAY-1487
> URL: https://issues.apache.org/jira/browse/CAY-1487
> Project: Cayenne
> Issue Type: Bug
> Components: Core Library
> Affects Versions: 2.0 branch
> Reporter: Donald Vrakking
>
> The method ObjectStore.registerNode(..) is not synchronized, while getNode(..) is. The objectMap can be accessed in a thread-unsafe way when a new object instance is created and when at the same time snapshotevents are processed.
> When creating the instance, the unsafe registerNode method is used. It will start looping in the objectMap when at the same time when an EventDispatch thread tries to acces the objectMap through getNode(). The dispatch threads will go in a WAIT state which eventually results in a completely frozen application.
> I noticed that in cayenne 3 the registerNode() method is synchronized. Can such a fix also be applied to a cayenne 2.0.5 release?
--
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.
[jira] Commented: (CAY-1487) Access to ObjectStore.objectMap not
thread safe when creating new object instance (and processing snaphot
events)
Posted by "Andrus Adamchik (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/CAY-1487?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12917587#action_12917587 ]
Andrus Adamchik commented on CAY-1487:
--------------------------------------
Sorry, was going to follow up on this, but it fell through the cracks... Are you actually seeing a problem with this code (map corruption), or did you find it via a code review? I am asking cause a quick check of the 2.0 code shows that invocations of 'registerNode' have external synchronization by the caller. E.g. in DataContext:
synchronized (getGraphManager()) {
localObject = (Persistent) descriptor.createObject();
localObject.setObjectContext(this);
localObject.setObjectId(id);
getGraphManager().registerNode(id, localObject);
}
So while this may not be intuitive, it is not actually going to cause problems (as far as I can tell).
> Access to ObjectStore.objectMap not thread safe when creating new object instance (and processing snaphot events)
> -----------------------------------------------------------------------------------------------------------------
>
> Key: CAY-1487
> URL: https://issues.apache.org/jira/browse/CAY-1487
> Project: Cayenne
> Issue Type: Bug
> Components: Core Library
> Affects Versions: 2.0 branch
> Reporter: Donald Vrakking
>
> The method ObjectStore.registerNode(..) is not synchronized, while getNode(..) is. The objectMap can be accessed in a thread-unsafe way when a new object instance is created and when at the same time snapshotevents are processed.
> When creating the instance, the unsafe registerNode method is used. It will start looping in the objectMap when at the same time when an EventDispatch thread tries to acces the objectMap through getNode(). The dispatch threads will go in a WAIT state which eventually results in a completely frozen application.
> I noticed that in cayenne 3 the registerNode() method is synchronized. Can such a fix also be applied to a cayenne 2.0.5 release?
--
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.
[jira] Commented: (CAY-1487) Access to ObjectStore.objectMap not
thread safe when creating new object instance (and processing snaphot
events)
Posted by "Donald Vrakking (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/CAY-1487?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12917619#action_12917619 ]
Donald Vrakking commented on CAY-1487:
--------------------------------------
It occurs when the app is running in production. These are the traces taken using a profiler:
TP-Processor17 [RUNNABLE] CPU time: 50:37
java.util.HashMap.put(Object, Object)
org.apache.cayenne.access.ObjectStore.registerNode(Object, Object)
org.apache.cayenne.access.ObjectStore.recordObjectCreated(Persistent)
org.apache.cayenne.access.DataContext.createAndRegisterNewObject(String)
org.apache.cayenne.access.DataContext.createAndRegisterNewObject(Class)
EventDispatchThread-3 [RUNNABLE] CPU time: 49:02
java.util.HashMap.get(Object)
org.apache.cayenne.access.ObjectStore.getNode(Object)
org.apache.cayenne.access.ObjectStore.processInvalidatedIDs(Collection)
org.apache.cayenne.access.ObjectStore.processSnapshotEvent(SnapshotEvent)
org.apache.cayenne.access.ObjectStore.snapshotsChanged(SnapshotEvent)
sun.reflect.GeneratedMethodAccessor6247.invoke(Object, Object[])
sun.reflect.DelegatingMethodAccessorImpl.invoke(Object, Object[])
java.lang.reflect.Method.invoke(Object, Object[])
org.apache.cayenne.util.Invocation.fire(Object[])
org.apache.cayenne.event.EventManager$InvocationDispatch.fire()
org.apache.cayenne.event.EventManager$DispatchThread.run()
The callstack from the first trace isn't synchronized at any point. Accessing the HashMap will cause both threads to spin forever. The other eventDispatchThreads will wait forever because the processSnapshotEvent is synchronized.
> Access to ObjectStore.objectMap not thread safe when creating new object instance (and processing snaphot events)
> -----------------------------------------------------------------------------------------------------------------
>
> Key: CAY-1487
> URL: https://issues.apache.org/jira/browse/CAY-1487
> Project: Cayenne
> Issue Type: Bug
> Components: Core Library
> Affects Versions: 2.0 branch
> Reporter: Donald Vrakking
>
> The method ObjectStore.registerNode(..) is not synchronized, while getNode(..) is. The objectMap can be accessed in a thread-unsafe way when a new object instance is created and when at the same time snapshotevents are processed.
> When creating the instance, the unsafe registerNode method is used. It will start looping in the objectMap when at the same time when an EventDispatch thread tries to acces the objectMap through getNode(). The dispatch threads will go in a WAIT state which eventually results in a completely frozen application.
> I noticed that in cayenne 3 the registerNode() method is synchronized. Can such a fix also be applied to a cayenne 2.0.5 release?
--
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.
[jira] Commented: (CAY-1487) Access to ObjectStore.objectMap not
thread safe when creating new object instance (and processing snaphot
events)
Posted by "Andrus Adamchik (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/CAY-1487?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12917622#action_12917622 ]
Andrus Adamchik commented on CAY-1487:
--------------------------------------
Thanks for the details. We'll fix it.
> Access to ObjectStore.objectMap not thread safe when creating new object instance (and processing snaphot events)
> -----------------------------------------------------------------------------------------------------------------
>
> Key: CAY-1487
> URL: https://issues.apache.org/jira/browse/CAY-1487
> Project: Cayenne
> Issue Type: Bug
> Components: Core Library
> Affects Versions: 2.0 branch
> Reporter: Donald Vrakking
>
> The method ObjectStore.registerNode(..) is not synchronized, while getNode(..) is. The objectMap can be accessed in a thread-unsafe way when a new object instance is created and when at the same time snapshotevents are processed.
> When creating the instance, the unsafe registerNode method is used. It will start looping in the objectMap when at the same time when an EventDispatch thread tries to acces the objectMap through getNode(). The dispatch threads will go in a WAIT state which eventually results in a completely frozen application.
> I noticed that in cayenne 3 the registerNode() method is synchronized. Can such a fix also be applied to a cayenne 2.0.5 release?
--
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.
[jira] Commented: (CAY-1487) Access to ObjectStore.objectMap not
thread safe when creating new object instance (and processing snaphot
events)
Posted by "Donald Vrakking (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/CAY-1487?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12922042#action_12922042 ]
Donald Vrakking commented on CAY-1487:
--------------------------------------
The most obvious question; do you have an indication on when you have a fix ready? ;-)
Or is there something we can try? In cayenne 3 the method ObjectStore.registerNode is synchronized. Is that all that need to be done or are there other considerations?
> Access to ObjectStore.objectMap not thread safe when creating new object instance (and processing snaphot events)
> -----------------------------------------------------------------------------------------------------------------
>
> Key: CAY-1487
> URL: https://issues.apache.org/jira/browse/CAY-1487
> Project: Cayenne
> Issue Type: Bug
> Components: Core Library
> Affects Versions: 2.0 branch
> Reporter: Donald Vrakking
>
> The method ObjectStore.registerNode(..) is not synchronized, while getNode(..) is. The objectMap can be accessed in a thread-unsafe way when a new object instance is created and when at the same time snapshotevents are processed.
> When creating the instance, the unsafe registerNode method is used. It will start looping in the objectMap when at the same time when an EventDispatch thread tries to acces the objectMap through getNode(). The dispatch threads will go in a WAIT state which eventually results in a completely frozen application.
> I noticed that in cayenne 3 the registerNode() method is synchronized. Can such a fix also be applied to a cayenne 2.0.5 release?
--
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.
[jira] Commented: (CAY-1487) Access to ObjectStore.objectMap not
thread safe when creating new object instance (and processing snaphot
events)
Posted by "Donald Vrakking (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/CAY-1487?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12922067#action_12922067 ]
Donald Vrakking commented on CAY-1487:
--------------------------------------
I don't see us upgrading to 3.x on the short term. It will require some (re)engineering effort.
> Access to ObjectStore.objectMap not thread safe when creating new object instance (and processing snaphot events)
> -----------------------------------------------------------------------------------------------------------------
>
> Key: CAY-1487
> URL: https://issues.apache.org/jira/browse/CAY-1487
> Project: Cayenne
> Issue Type: Bug
> Components: Core Library
> Affects Versions: 2.0 branch
> Reporter: Donald Vrakking
>
> The method ObjectStore.registerNode(..) is not synchronized, while getNode(..) is. The objectMap can be accessed in a thread-unsafe way when a new object instance is created and when at the same time snapshotevents are processed.
> When creating the instance, the unsafe registerNode method is used. It will start looping in the objectMap when at the same time when an EventDispatch thread tries to acces the objectMap through getNode(). The dispatch threads will go in a WAIT state which eventually results in a completely frozen application.
> I noticed that in cayenne 3 the registerNode() method is synchronized. Can such a fix also be applied to a cayenne 2.0.5 release?
--
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.
[jira] Commented: (CAY-1487) Access to ObjectStore.objectMap not
thread safe when creating new object instance (and processing snaphot
events)
Posted by "Donald Vrakking (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/CAY-1487?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12917583#action_12917583 ]
Donald Vrakking commented on CAY-1487:
--------------------------------------
Is there any followup on this?
> Access to ObjectStore.objectMap not thread safe when creating new object instance (and processing snaphot events)
> -----------------------------------------------------------------------------------------------------------------
>
> Key: CAY-1487
> URL: https://issues.apache.org/jira/browse/CAY-1487
> Project: Cayenne
> Issue Type: Bug
> Components: Core Library
> Affects Versions: 2.0 branch
> Reporter: Donald Vrakking
>
> The method ObjectStore.registerNode(..) is not synchronized, while getNode(..) is. The objectMap can be accessed in a thread-unsafe way when a new object instance is created and when at the same time snapshotevents are processed.
> When creating the instance, the unsafe registerNode method is used. It will start looping in the objectMap when at the same time when an EventDispatch thread tries to acces the objectMap through getNode(). The dispatch threads will go in a WAIT state which eventually results in a completely frozen application.
> I noticed that in cayenne 3 the registerNode() method is synchronized. Can such a fix also be applied to a cayenne 2.0.5 release?
--
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.