To answer the easy question first, 0.32 clients should be totally compatible with an 0.16 broker.
In terms of the deadlock issue, I know there are a number of open deadlock JIRAs that Robbie and Rajith have looked at in the past... Hopefully one of them will be able to chip in here and discuss the feasibility of fixing your particular issue for 0.32. -- Rob On 4 February 2015 at 23:36, Helen Kwong <helenkw...@gmail.com> wrote: > Hi Qpid gurus, > > We are using 0.16 Java broker and client on 0-10, and we are running into > deadlock issues on the client that involve AMQSession's > _messageDeliveryLock and AMQConnection's _failoverMutex, where different > threads acquire them in different orders. This is leading to major > production headaches for us and has us very worried. > > (I've been looking at 0.16 code mostly but also skimmed the relevant parts > in 0.32, which seem largely the same in those places.) > > Deadlock Variety 1 > > This is an example of a deadlock we see, where the IOReceiver thread > deadlocks with Session dispatcher thread (we have listeners that call > session rollback or commit in onMessage()): > > IOReceiver > org.apache.qpid.client.AMQSession.closed(AMQSession.java:818) ----------> > waiting for session's messageDeliveryLock > > org.apache.qpid.client.AMQConnection.closeAllSessions(AMQConnection.java:938) > > org.apache.qpid.client.AMQConnection.exceptionReceived(AMQConnection.java:1282) > ----------> acquires connection's failoverMutex > > org.apache.qpid.client.AMQSession_0_10.setCurrentException(AMQSession_0_10.java:1057) > org.apache.qpid.client.AMQSession_0_10.exception(AMQSession_0_10.java:907) > > org.apache.qpid.transport.SessionDelegate.executionException(SessionDelegate.java:182) > > org.apache.qpid.transport.SessionDelegate.executionException(SessionDelegate.java:32) > > org.apache.qpid.transport.ExecutionException.dispatch(ExecutionException.java:103) > org.apache.qpid.transport.SessionDelegate.command(SessionDelegate.java:55) > org.apache.qpid.transport.SessionDelegate.command(SessionDelegate.java:50) > org.apache.qpid.transport.SessionDelegate.command(SessionDelegate.java:32) > org.apache.qpid.transport.Method.delegate(Method.java:159) > org.apache.qpid.transport.Session.received(Session.java:585) > org.apache.qpid.transport.Connection.dispatch(Connection.java:412) > > org.apache.qpid.transport.ConnectionDelegate.handle(ConnectionDelegate.java:64) > > org.apache.qpid.transport.ConnectionDelegate.handle(ConnectionDelegate.java:40) > > org.apache.qpid.transport.MethodDelegate.executionException(MethodDelegate.java:110) > > org.apache.qpid.transport.ExecutionException.dispatch(ExecutionException.java:103) > > org.apache.qpid.transport.ConnectionDelegate.command(ConnectionDelegate.java:54) > > org.apache.qpid.transport.ConnectionDelegate.command(ConnectionDelegate.java:40) > org.apache.qpid.transport.Method.delegate(Method.java:159) > org.apache.qpid.transport.Connection.received(Connection.java:367) > org.apache.qpid.transport.Connection.received(Connection.java:65) > org.apache.qpid.transport.network.Assembler.emit(Assembler.java:97) > org.apache.qpid.transport.network.Assembler.assemble(Assembler.java:198) > org.apache.qpid.transport.network.Assembler.frame(Assembler.java:131) > org.apache.qpid.transport.network.Frame.delegate(Frame.java:128) > org.apache.qpid.transport.network.Assembler.received(Assembler.java:102) > org.apache.qpid.transport.network.Assembler.received(Assembler.java:44) > org.apache.qpid.transport.network.InputHandler.next(InputHandler.java:189) > > org.apache.qpid.transport.network.InputHandler.received(InputHandler.java:105) > > org.apache.qpid.transport.network.InputHandler.received(InputHandler.java:44) > org.apache.qpid.transport.network.io.IoReceiver.run(IoReceiver.java:152) > java.lang.Thread.run(Thread.java:745) > > Session dispatcher thread > > org.apache.qpid.client.AMQConnection.exceptionReceived(AMQConnection.java:1255) > ---------> waiting for connection's failoverMutex > > org.apache.qpid.client.AMQSession_0_10.setCurrentException(AMQSession_0_10.java:1057) > org.apache.qpid.client.AMQSession_0_10.sync(AMQSession_0_10.java:1034) > > org.apache.qpid.client.AMQSession_0_10.sendSuspendChannel(AMQSession_0_10.java:812) > org.apache.qpid.client.AMQSession.suspendChannel(AMQSession.java:3075) > org.apache.qpid.client.AMQSession.rollback(AMQSession.java:1837) > common.messaging.QpidSession.rollback(QpidSession.java:211) > > common.messaging.QpidMessageHandler.rollbackSession(QpidMessageHandler.java:284) > common.messaging.QpidMessageHandler.onMessage(QpidMessageHandler.java:113) > > org.apache.qpid.client.BasicMessageConsumer.notifyMessage(BasicMessageConsumer.java:748) > > org.apache.qpid.client.BasicMessageConsumer_0_10.notifyMessage(BasicMessageConsumer_0_10.java:141) > > org.apache.qpid.client.BasicMessageConsumer.notifyMessage(BasicMessageConsumer.java:722) > > org.apache.qpid.client.BasicMessageConsumer_0_10.notifyMessage(BasicMessageConsumer_0_10.java:186) > > org.apache.qpid.client.BasicMessageConsumer_0_10.notifyMessage(BasicMessageConsumer_0_10.java:54) > > org.apache.qpid.client.AMQSession$Dispatcher.notifyConsumer(AMQSession.java:3454) > > org.apache.qpid.client.AMQSession$Dispatcher.dispatchMessage(AMQSession.java:3393) > -----------> acquires session's messageDeliverylock > > org.apache.qpid.client.AMQSession$Dispatcher.access$1000(AMQSession.java:3180) > org.apache.qpid.client.AMQSession.dispatch(AMQSession.java:3173) > > org.apache.qpid.client.message.UnprocessedMessage.dispatch(UnprocessedMessage.java:54) > org.apache.qpid.client.AMQSession$Dispatcher.run(AMQSession.java:3316) > java.lang.Thread.run(Thread.java:745) > > The problem is that the IOReceiver thread acquires failoverMutex before > messageDeliveryLock (for each session), whereas the dispatcher thread > acquires it in the other order. We also see potential problems where other > threads (instead of IOReceiver) can deadlock with the dispatcher thread, as > long as it acquires failoverMutex before messageDeliveryLock. Examples we > can think of: > > A) Another thread calling AMQSession.close() > B) Another thread calling BasicMessageConsumer.close() > C) Same connection, different session's dispatcher thread, calling > rollback() or commit() -> sync() -> setCurrentException() -> > AMQConnection.exceptionReceived() -> AMQConnection.closeAllSessions(), > which can try to acquire the messageDeliveryLock of another session and > deadlock with the other session's dispatcher thread > > > Deadlock Variety 2: > From code inspection, it also appears that AMQConnection.close() can > deadlock with either AMQSession.close() or BasicMessageConsumer.close() > (where the session / consumer is on the same connection). This is because > AMQConnection.close() first acquires the messageDeliveryLock of all its > sessions in the recursive doClose(), before trying to acquire the > connection's failoverMutex. But the Session / consumer's close() acquires > the failoverMutex before messageDeliveryLock. We haven't seen this happen > but would like to know if this is possible. > > > We'd really appreciate your help on this. Assuming these can be fixed in > 0.32, we are also wondering if clients are backward compatible -- i.e., can > we upgrade only our client to 0.32 while continuing to use the 0.16 broker? > > Thanks, > Helen >
