activemq-users mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Gary Tully <gary.tu...@gmail.com>
Subject Re: CountDownLatch problem . MultiCast Discovery and refusal of connection on DUPLEX connection (Fuse 5.3.0.5) .
Date Tue, 06 Jul 2010 12:03:08 GMT
Hi, as you can see, this is a complicated area of the code. The best
approach is to try and produce a test case for your scenario. Take a
look at the test: BrokerQueueNetworkWithDisconnectTest in
activemq-core. This can simulate network failures and can use
multicast (bridgeAllBrokers). Getting a reproducible test case is the
best way to validate your changes and protect them into the future.

The only other alternative is to keep adding your suggestions to the
jira issue (https://issues.apache.org/activemq/browse/AMQ-2774) and
with a bit of luck I (or some one else) will have a change to look at
it before 5.4 .


On 6 July 2010 12:37, Eric-AWL <eric.vincent@atosorigin.com> wrote:
>
> I wonder if it could not have some undesirable effects on both side of the
> duplex connection ....
>
> perhaps we should test the started AtomicBoolean, in the start() method
> after the corresponding "await" and shouldn't execute the end of the start
> method ?
>
>            if (configuration.isDuplex() && duplexInitiatingConnection ==
> null) {
>                // initiator side of duplex network
>                remoteBrokerNameKnownLatch.await();
>            }
>
> HERE ??? (if started.get()) { ???
>
>            try {
>                triggerRemoteStartBridge();
>            } catch (IOException e) {
>                LOG.warn("Caught exception from remote start", e);
>            }
>            NetworkBridgeListener l = this.networkBridgeListener;
>            if (l != null) {
>                l.onStart(this);
>            }
>
> It's the first big problem I have with ActiveMQ complex configuration, it
> happens when network is faulty (that happens not very often), and I don't
> know ActiveMQ source code very well ....
>
> Who could help me to identify potential effects of this change, before I try
> to modify it ? (I can't do that on my production system without some tests
> and expert validation)
>
> Eric-AWL
>
>
> Gary Tully wrote:
>>
>> that seems reasonable. want to submit a patch against trunk?
>>
>> On 6 July 2010 12:10, Eric-AWL <eric.vincent@atosorigin.com> wrote:
>>>
>>> What could happen if we add
>>>
>>>         if (configuration.isDuplex() && duplexInitiatingConnection
==
>>> null)
>>> {
>>>                // initiator side of duplex network
>>>                remoteBrokerNameKnownLatch.countDown();
>>>            }
>>>
>>> into the stop() method of DemandForwardingBridgeSupport class ?
>>>
>>> Eric-AWL
>>>
>>>
>>> Eric-AWL wrote:
>>>>
>>>> Hi
>>>>
>>>> I'm sure that I identified a Latch problem in Multicast Network
>>>> Discovery
>>>> mechanism on Duplex connection
>>>>
>>>> The multicast notifier thread is blocked. here the trace
>>>>
>>>> "Notifier-MulticastDiscoveryAgent-listener:DiscoveryNetworkConnector:NOCSupervisorP5-ADMIN-OUT-IN:BrokerService[SIBBusModule-NOCP5-tpnocp08s-bus]"
>>>> daemon prio=10 tid=0x0000000044ff2400 nid=0x1389 waiting on condition
>>>> [0x0000000044c26000..0x0000000044c26b90]
>>>>    java.lang.Thread.State: WAITING (parking)
>>>>       at sun.misc.Unsafe.park(Native Method)
>>>>       - parking to wait for  <0x00002aaab3dd66f0> (a
>>>> java.util.concurrent.CountDownLatch$Sync)
>>>>       at
>>>> java.util.concurrent.locks.LockSupport.park(LockSupport.java:158)
>>>>       at
>>>> java.util.concurrent.locks.AbstractQueuedSynchronizer.parkAndCheckInterrupt(AbstractQueuedSynchronizer.java:747)
>>>>       at
>>>> java.util.concurrent.locks.AbstractQueuedSynchronizer.doAcquireSharedInterruptibly(AbstractQueuedSynchronizer.java:905)
>>>>       at
>>>> java.util.concurrent.locks.AbstractQueuedSynchronizer.acquireSharedInterruptibly(AbstractQueuedSynchronizer.java:1217)
>>>>       at
>>>> java.util.concurrent.CountDownLatch.await(CountDownLatch.java:207)
>>>>       at
>>>> org.apache.activemq.network.DemandForwardingBridgeSupport.start(DemandForwardingBridgeSupport.java:231)
>>>>       at
>>>> org.apache.activemq.network.DiscoveryNetworkConnector.onServiceAdd(DiscoveryNetworkConnector.java:114)
>>>>       at
>>>> org.apache.activemq.transport.discovery.multicast.MulticastDiscoveryAgent$2.run(MulticastDiscoveryAgent.java:484)
>>>>       at
>>>> java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
>>>>       at
>>>> java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
>>>>       at java.lang.Thread.run(Thread.java:619)
>>>>
>>>> The problem appears when the network is quickly and alternatively on/off
>>>> between the two components.
>>>> The bridge is created in one direction, but the answer can not be
>>>> received.
>>>>
>>>> The thread is blocked on the CountDownLatch. Even if multicast frames
>>>> are
>>>> received, the component can not establish a new network connection.
>>>>
>>>> Here are an corresponding activemq trace
>>>>
>>>> When it is OK :
>>>> 2010-06-22 22:56:24,500 [-tpnocp08s-bus]] INFO
>>>>  DiscoveryNetworkConnector
>>>> - Establishing network connection from
>>>> vm://SIBBusModule-NOCP5-tpnocp08s-bus to
>>>> tcp://tpnocp11v-bus.vdm.priv.amm.noc:14101?useLocalHost=false
>>>> 2010-06-22 22:56:26,083 [nocp08s-bus#160] INFO  DemandForwardingBridge
>>>> - Network connection between vm://SIBBusModule-NOCP5-tpnocp08s-bus#160
>>>> and
>>>> tcp://tpnocp11v-bus.vdm.priv.amm.noc/10.18.126.30:14101(SIBBusSupervisor-tpnocp11v-bus)
>>>> has been established.
>>>>
>>>> 2010-06-22 22:57:34,807 [-tpnocp08s-bus]] INFO  DemandForwardingBridge
>>>> - SIBBusModule-NOCP5-tpnocp08s-bus bridge to
>>>> SIBBusSupervisor-tpnocp11v-bus stopped
>>>>
>>>> 2010-06-22 22:57:34,811 [-tpnocp08s-bus]] INFO
>>>>  DiscoveryNetworkConnector
>>>> - Establishing network connection from
>>>> vm://SIBBusModule-NOCP5-tpnocp08s-bus to
>>>> tcp://tpnocp11v-bus.vdm.priv.amm.noc:14101?useLocalHost=false
>>>> 2010-06-22 22:57:39,064 [nocp08s-bus#162] INFO  DemandForwardingBridge
>>>> - Network connection between vm://SIBBusModule-NOCP5-tpnocp08s-bus#162
>>>> and
>>>> tcp://tpnocp11v-bus.vdm.priv.amm.noc/10.18.126.30:14101(SIBBusSupervisor-tpnocp11v-bus)
>>>> has been established.
>>>>
>>>> 2010-06-22 22:58:42,578 [-tpnocp08s-bus]] INFO  DemandForwardingBridge
>>>> - SIBBusModule-NOCP5-tpnocp08s-bus bridge to
>>>> SIBBusSupervisor-tpnocp11v-bus stopped
>>>>
>>>> When it is KO : "Unknown"
>>>>
>>>> 2010-06-22 22:58:42,648 [-tpnocp08s-bus]] INFO
>>>>  DiscoveryNetworkConnector
>>>> - Establishing network connection from
>>>> vm://SIBBusModule-NOCP5-tpnocp08s-bus to
>>>> tcp://tpnocp11v-bus.vdm.priv.amm.noc:14101?useLocalHost=false
>>>> 2010-06-22 22:59:18,031 [18.126.30:14101] WARN  DemandForwardingBridge
>>>> - Network connection between vm://SIBBusModule-NOCP5-tpnocp08s-bus#164
>>>> and
>>>> tcp://tpnocp11v-bus.vdm.priv.amm.noc/10.18.126.30:14101 shutdown due to
>>>> a
>>>> remote error: java.net.SocketException: Connection reset
>>>> 2010-06-22 22:59:18,033 [NetworkBridge  ] INFO  DemandForwardingBridge
>>>> - SIBBusModule-NOCP5-tpnocp08s-bus bridge to Unknown stopped
>>>>
>>>>
>>>> Here is the other side corresponding activemq trace
>>>>
>>>> activemq-server.log:2010-06-22 22:55:44,295 [26.190.27:40517] INFO
>>>> TransportConnection            - Created Duplex Bridge back to
>>>> SIBBusModule-NOCP5-tpnocp08s-bus
>>>>
>>>> activemq-server.log:2010-06-22 22:56:24,438 [26.190.27:40517] INFO
>>>> DemandForwardingBridge         - SIBBusSupervisor-tpnocp11v-bus bridge
>>>> to
>>>> SIBBusModule-NOCP5-tpnocp08s-bus stopped
>>>>
>>>> activemq-server.log:2010-06-22 22:56:26,135 [26.190.27:40518] INFO
>>>> TransportConnection            - Created Duplex Bridge back to
>>>> SIBBusModule-NOCP5-tpnocp08s-bus
>>>> activemq-server.log:2010-06-22 22:56:26,135 [ocp11v-bus#1770] INFO
>>>> DemandForwardingBridge         - Network connection between
>>>> vm://SIBBusSupervisor-tpnocp11v-bus#1770 and
>>>> tcp:///10.26.190.27:40518(SIBBusModule-NOCP5-tpnocp08s-bus) has been
>>>> established.
>>>>
>>>> activemq-server.log:2010-06-22 22:57:34,818 [26.190.27:40518] INFO
>>>> DemandForwardingBridge         - SIBBusSupervisor-tpnocp11v-bus bridge
>>>> to
>>>> SIBBusModule-NOCP5-tpnocp08s-bus stopped
>>>>
>>>> activemq-server.log:2010-06-22 22:57:39,153 [26.190.27:40519] INFO
>>>> TransportConnection            - Created Duplex Bridge back to
>>>> SIBBusModule-NOCP5-tpnocp08s-bus
>>>> activemq-server.log:2010-06-22 22:57:39,153 [ocp11v-bus#1806] INFO
>>>> DemandForwardingBridge         - Network connection between
>>>> vm://SIBBusSupervisor-tpnocp11v-bus#1806 and
>>>> tcp:///10.26.190.27:40519(SIBBusModule-NOCP5-tpnocp08s-bus) has been
>>>> established.
>>>>
>>>> activemq-server.log:2010-06-22 22:58:44,328 [26.190.27:40519] INFO
>>>> DemandForwardingBridge         - SIBBusSupervisor-tpnocp11v-bus bridge
>>>> to
>>>> SIBBusModule-NOCP5-tpnocp08s-bus stopped
>>>>
>>>>
>>>> Eric-AWL
>>>>
>>>
>>> --
>>> View this message in context:
>>> http://old.nabble.com/MultiCast-Discovery-and-refusal-of-connection-tp28827529p29084235.html
>>> Sent from the ActiveMQ - User mailing list archive at Nabble.com.
>>>
>>>
>>
>>
>>
>> --
>> http://blog.garytully.com
>>
>> Open Source Integration
>> http://fusesource.com
>>
>>
>
> --
> View this message in context: http://old.nabble.com/MultiCast-Discovery-and-refusal-of-connection-tp28827529p29084410.html
> Sent from the ActiveMQ - User mailing list archive at Nabble.com.
>
>



-- 
http://blog.garytully.com

Open Source Integration
http://fusesource.com

Mime
View raw message