Hmm... I don't see a deadlock, just a contention with other threads
waiting for "userDataBeanMessageListener-5" to finish commit. So does
it result in slowness or a complete deadlock?
(there are known issues with nested contexts [1], but there weren't
any with the top-level contexts in a while).
Andrus
[1] https://issues.apache.org/cayenne/browse/CAY-957
On May 15, 2008, at 11:02 AM, Martin Thelian wrote:
> Hi,
>
> in our application we are using cayenne 1.2.4 and have the problem
> that
> we run into a deadlock if two users try to update their data in
> parallel. I've analyzed the thread-dumps and this are the threads that
> are involved:
>
> ------------------------------------------
> "userDataBeanMessageListener-5" prio=1 tid=0x08f85f58 nid=0x53d3
> runnable [0x83cf5000..0x83cf6e30]
> at java.net.SocketInputStream.socketRead0(Native Method)
> at java.net.SocketInputStream.read(SocketInputStream.java:129)
> at java.io.BufferedInputStream.fill(BufferedInputStream.java:
> 218)
> at java.io.BufferedInputStream.read(BufferedInputStream.java:
> 235)
> - locked <0x9303e150> (a java.io.BufferedInputStream)
> at org.postgresql.core.PGStream.ReceiveChar(PGStream.java:256)
> at
> org
> .postgresql
> .core.v3.QueryExecutorImpl.processResults(QueryExecutorImpl.java:1163)
> at
> org
> .postgresql.core.v3.QueryExecutorImpl.execute(QueryExecutorImpl.java:
> 347)
> - locked <0x93027df8> (a
> org.postgresql.core.v3.QueryExecutorImpl)
> at
> org
> .postgresql
> .jdbc2
> .AbstractJdbc2Statement.executeBatch(AbstractJdbc2Statement.java:2574)
> at
> org
> .objectstyle
> .cayenne.access.jdbc.BatchAction.runAsBatch(BatchAction.java:164)
> at
> org
> .objectstyle
> .cayenne.access.jdbc.BatchAction.performAction(BatchAction.java:114)
> at
> org
> .objectstyle
> .cayenne
> .access.DataNodeQueryAction.runQuery(DataNodeQueryAction.java:95)
> at
> org.objectstyle.cayenne.access.DataNode.performQueries(DataNode.java:
> 309)
> at
> org
> .objectstyle
> .cayenne
> .access.DataDomainFlushAction.runQueries(DataDomainFlushAction.java:
> 255)
> at
> org
> .objectstyle
> .cayenne
> .access.DataDomainFlushAction.flush(DataDomainFlushAction.java:177)
> - locked <0x92f78110> (a
> org.objectstyle.cayenne.access.DataRowStore)
> at
> org
> .objectstyle.cayenne.access.DataDomain.onSyncFlush(DataDomain.java:
> 846)
> at
> org.objectstyle.cayenne.access.DataDomain
> $2.transform(DataDomain.java:817)
> at
> org
> .objectstyle
> .cayenne.access.DataDomain.runInTransaction(DataDomain.java:862)
> at
> org.objectstyle.cayenne.access.DataDomain.onSync(DataDomain.java:814)
> at
> org
> .objectstyle
> .cayenne.access.DataContext.flushToParent(DataContext.java:1270)
> - locked <0x8eff78d8> (a
> org.objectstyle.cayenne.access.ObjectStore)
> at
> org
> .objectstyle
> .cayenne.access.DataContext.commitChanges(DataContext.java:1174)
> at
> cc
> .lovo
> .data
> .cayenne.CayenneUserDataBean.setUserData(CayenneUserDataBean.java:851)
> at
> cc
> .lovo
> .data
> .cayenne.CayenneUserDataBean.createUser(CayenneUserDataBean.java:627)
> [...]
>
> "userDataBeanMessageListener-1" prio=1 tid=0x08f81cd0 nid=0x53cf
> waiting
> for monitor entry [0x83ef9000..0x83efb030]
> at
> org
> .objectstyle
> .cayenne
> .access.DataRowStore.snapshotsUpdatedForObjects(DataRowStore.java:272)
> - waiting to lock <0x92f78110> (a
> org.objectstyle.cayenne.access.DataRowStore)
> at
> org
> .objectstyle
> .cayenne
> .access.ObjectResolver.objectsFromDataRows(ObjectResolver.java:157)
> at
> org
> .objectstyle
> .cayenne
> .access
> .ObjectResolver.synchronizedObjectsFromDataRows(ObjectResolver.java:
> 133)
> - locked <0x8eff7dc8> (a
> org.objectstyle.cayenne.access.ObjectStore)
> at
> org
> .objectstyle
> .cayenne
> .access
> .DataDomainQueryAction
> .interceptObjectConversion(DataDomainQueryAction.java:355)
> at
> org
> .objectstyle
> .cayenne
> .access.DataDomainQueryAction.execute(DataDomainQueryAction.java:152)
> at
> org.objectstyle.cayenne.access.DataDomain.onQuery(DataDomain.java:782)
> at
> org
> .objectstyle
> .cayenne
> .util
> .ObjectContextQueryAction.runQuery(ObjectContextQueryAction.java:253)
> at
> org
> .objectstyle
> .cayenne
> .access.DataContextQueryAction.execute(DataContextQueryAction.java:90)
> at
> org.objectstyle.cayenne.access.DataContext.onQuery(DataContext.java:
> 1431)
> at
> org
> .objectstyle
> .cayenne.access.DataContext.performQuery(DataContext.java:1420)
> at
> cc
> .lovo
> .data
> .cayenne.common.CayenneDataBean.getMBForLanCou(CayenneDataBean.java:
> 156)
> at
> cc
> .lovo
> .data
> .cayenne.common.CayenneDataBean.getCurrLocale(CayenneDataBean.java:
> 177)
> at
> cc
> .lovo
> .data
> .cayenne.CayenneUserDataBean.getProfileData(CayenneUserDataBean.java:
> 199)
> at
> cc
> .lovo
> .data.cayenne.CayenneUserDataBean.getUser(CayenneUserDataBean.java:
> 147)
> [...]
>
> "EventDispatchThread-4" daemon prio=1 tid=0x85b9e280 nid=0x5488
> waiting
> for monitor entry [0x7d428000..0x7d429030]
> at
> org
> .objectstyle
> .cayenne.access.ObjectStore.processSnapshotEvent(ObjectStore.java:813)
> - waiting to lock <0x8eff78d8> (a
> org.objectstyle.cayenne.access.ObjectStore)
> at
> org
> .objectstyle
> .cayenne.access.ObjectStore.snapshotsChanged(ObjectStore.java:804)
> at sun.reflect.GeneratedMethodAccessor113.invoke(Unknown
> Source)
> at
> sun
> .reflect
> .DelegatingMethodAccessorImpl
> .invoke(DelegatingMethodAccessorImpl.java:25)
> at java.lang.reflect.Method.invoke(Method.java:585)
> at
> org.objectstyle.cayenne.util.Invocation.fire(Invocation.java:240)
> at
> org.objectstyle.cayenne.event.EventManager
> $InvocationDispatch.fire(EventManager.java:452)
> at
> org.objectstyle.cayenne.event.EventManager
> $DispatchThread.run(EventManager.java:499)
>
> ------------------------------------------
>
> The thread "userDataBeanMessageListener-5" seem to lock the whole
> DataRowCache via a call to function
> org
> .objectstyle
> .cayenne
> .access.DataDomainFlushAction.flush(DataDomainFlushAction.java:177):
>
> |> synchronized (context.getObjectStore().getDataRowCache()) {
> |> [...]
> |> runQueries();
> |> [...]
> |> }
>
> but itself seems to wait via Socket-read for the thread
> userDataBeanMessageListener-1 to finishes its DB-query. The Problem is
> that this thread also tries to enter a sync block in the DataRowStore
> but blocks.
>
> The relevant code in
> org
> .objectstyle
> .cayenne
> .access.DataRowStore.snapshotsUpdatedForObjects(DataRowStore.java:
> 272):
>
> |> void snapshotsUpdatedForObjects(List objects, List snapshots,
> boolean refresh) {
> |> [...]
> |>
> |> synchronized (this) {
> |> [...]
>
>
> A third thread also seems to try to enter a synchronized block in
> |> synchronized void processSnapshotEvent(SnapshotEvent event) {
> |> [...]
> |> }
>
>
> Any hints how we can get around this problem?
>
> Thanks,
> Martin
>
This archive was generated by hypermail 2.0.0 : Thu May 15 2008 - 11:44:10 EDT