[rabbitmq-discuss] Bug: Java ConnectionFactory can hangs forever in network packet loss cases

[Steve Powell]

Ildar,

Just a note to confirm that this bug is now fixed and will be in the next release.

Steve Powell  (a funny bunny)
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On 16 Feb 2012, at 13:27, Steve Powell wrote:

> Dear Ildar,
> 
> First, may I apologise for not getting back to you sooner. It seems that you
> have clearly identified a bug, and have helped to narrow it down for us.
> 
> Thank you very much. I have raised a problem for us to fix and track this
> (24747).
> 
> I have a few comments regarding your settings: it seems to me that a heartbeat
> of 30s is not unreasonable, but you should be aware that anything up to a minute
> may pass before noticing that a heartbeat is missed, so you must not rely on
> this interval.
> 
> The ConnectionTimeout will only affect waiting for the socket connection so is
> not involved in this. I think your interval here is again quite large, but not
> unreasonable in unreliable networks. I would expect the herartbeat to be about
> half of this (see note above).
> 
> We'll get on to this bug asap.
> Steve Powell
> steve at rabbitmq.com
> [wrk: +44-2380-111-528] [mob: +44-7815-838-558]
> 
> On 13 Feb 2012, at 09:28, Ильдар Нурисламов wrote:
> 
>> Can anybody help with this problem or prove that i'm wrong?
>> 
>> 2012/2/7 Ильдар Нурисламов <absorbb at gmail.com>
>> Hello.
>> 
>> We have rabbitMQ 2.7.1 java clients remotely connected to the server.
>> We started experience short-term bad network scenarios and serious problem occurred:
>> 1. factory.setRequestedHeartbeat set to 30s
>> 2. factory.setConnectionTimeout set to 30000ms
>> client properly closes connection after missing 30 seconds of heartbeats.
>> But sometimes it hangs completely when tries to open a new connection.
>> 
>> I tried to analyze java client code and what is result:
>> 
>> AMQConnection.java:286 :
>>          _frameHandler.setTimeout(HANDSHAKE_TIMEOUT); - socket.soTimeout is set to 10s here
>> then it starts the MainLoop at line 294
>> and blocks till get a reply for a handshake at line 300:
>>     connStart =
>>                (AMQP.Connection.Start) connStartBlocker.getReply().getMethod();
>> 
>> problem is that it's possible that it'll never get a reply. Because MainLoop relies on heartbeats functional to handle such situation which is not enabled yet. It happens only at line 368:
>>            setHeartbeat(heartbeat);
>> MainLoop endlessly runs at 492:              
>>    Frame frame = _frameHandler.readFrame();
>> which returns null every 10s (this is how SocketTimeoutException handled in Frame.readFrom..)
>> and handleSocketTimeout() do nothing because _heartbeat is not set yet.
>> 
>> Thanks.
>> 
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> 
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