[rabbitmq-discuss] RabbitMQ server closing connection every few minutes

Tue May 22 09:00:49 BST 2012

On 22/05/2012 08:48, Tim Watson wrote:
> On 22/05/2012 07:34, David Tinker wrote:
>> Hi
>>
>> We have a Java application using RabbitMQ that keeps getting its
>> connection closed by the server every few minutes. On the client side
>> we see this:
>>
>> 2012-05-22 05:30:05,337 [AMQP Connection 127.0.0.1:5671] ERROR
>> pork.RabbitService - Connection to Rabbit Exchange shutting down:
>> com.rabbitmq.client.ShutdownSignalException: connection error; reason:
>> java.net.SocketException: Connection reset
>> Reason: java.net.SocketException: Connection reset
>>
>> On the server side we get this:
>>
>> =INFO REPORT==== 22-May-2012::05:25:20 ===
>> accepting AMQP connection<0.32660.612> (127.0.0.1:45458 ->
>> 127.0.0.1:5671)
>>
>> =ERROR REPORT==== 22-May-2012::05:30:05 ===
>> closing AMQP connection<0.32660.612> (127.0.0.1:45458 -> 127.0.0.1:5671):
>> {timeout,running}
>>
>
> Hi David. The second error message will appear in the logs when there
> has been an un-handled exception in rabbit's 'reader process'. The
> '{timeout, running}' state occurs when receiving data from the network
> takes too long (which is where the 'timeout' tag originates) but the
> AMQP connection state is 'running' - the second tag. When this condition
> arises, the broker's reader process shuts down the connection.
>
> So at first glance, it does look like a networking problem to me,
> although TBH I'm not sure about the nature of it just yet. I suspect it
> could have something to do with "... It can sometimes be several minutes
> before a message is acked or nacked ...".
>
>> It happens more frequently when the system is busy (500-1000
>> messages/s) than when it is cruising (50 messages/s). The application
>> and RabbitMQ are on the same box so I don't think its a
>> networking/firewall problem.
>>
>> The application only uses one connection and one channel. Messages are
>> received using Connection.basicConsume(..) and acked or nacked
>> sometime later on different threads. It can sometimes be several
>> minutes before a message is acked or nacked. We are using
>> Connection.basicQos(10000) to limit the number of outstanding messages
>> but its not often that reaches 10000 and the error happens anytime.
>> There is defensive code to make sure messages are not acked/nacked
>> more than once.
>>
>> Anyone have any ideas? Is there any way to get more information on the
>> server or client side regarding the error?
>>
>
> Well the server error seems pretty clear and just to be 100% sure, I can
> verify that the error message you're seeing is only generated in one
> place in the whole code base:
> https://github.com/rabbitmq/rabbitmq-server/blob/master/src/rabbit_reader.erl#L241.
>
>

Except that this isn't quite as clear as I suggested initially. The 
networking layer isn't going to send a timeout on a blocking receive 
like this - the 'timeout' message is being sent to the reader from some 
other process. I will investigate further! :)

> The code handling the timeout condition is
> https://github.com/rabbitmq/rabbitmq-server/blob/master/src/rabbit_reader.erl#L321,
> the call site for which is
> https://github.com/rabbitmq/rabbitmq-server/blob/master/src/rabbit_reader.erl#L284.
> The origin of this is
> https://github.com/rabbitmq/rabbitmq-server/blob/master/src/rabbit_net.erl#L108
> in rabbit_net - what the code does is make the calling process wait for
> a message from the Erlang networking layer. So it is the underlying
> TCP/IP layer in Erlang which is noticing a timeout on the connection.
>
> How this is mediated through the client's behaviour is another matter.
>
> Hope this helps us get started figuring out what's wrong!
>
> Cheers,
> Tim
>
>> RabbitMQ 2.8.1 on Gentoo Linux 64bit
>> Erlang R15B (erts-5.9) [source] [64-bit]
>> amqp-client-2.8.2 (also tried amqp-client-2.7.1)
>> java version "1.6.0_31"
>> Java(TM) SE Runtime Environment (build 1.6.0_31-b04)
>> Java HotSpot(TM) 64-Bit Server VM (build 20.6-b01, mixed mode)
>>
>> Thanks
>> David
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