[rabbitmq-discuss] Blocking Queue - Close connection by client

[Claire Fautsch]

Hi Michael and all,

Unfortunatelly calling the abort function instead of close, will show
exactly the same behaviour, as there is still a flush at the end (I also
tested this, and indeed not a solution). The only difference is that
Exceptions/Stacktraces are ignroed.
The only option I see so far to avoid hanging here, is to set a timeout to
the close method.

Regards
Claire


2014-03-03 9:18 GMT+01:00 Claire Fautsch <cfautsch at goodgamestudios.com>:

> Hi,
>
> we have following issue with blocking queues:
>
> Once the memory watermark is reached, the connection from the client gets
> blocked by the RabbitMQ server and it is no longer possible to publish
> messages.
>
> If this happens, we are for some time still able to publish  messages,
> however they remain in the socket's write buffer and are not actually
> published until the connection is un-blocked again. Once this buffer is
> full, publishing blocks completely.
>
> After some research we found out, that with a newer version of the
> official Java client, it is possible to use blocked connection
> notifications to react on this situation.
>
> Our prefered reaction would be to close the connection, and re-connect to
> another broker. Here however comes the problem: It is not possible to close
> the connection to the RabbitMQ, as the method to do so, involves a flush on
> the socket before the socket is closed and this is blocked as well.
>
> Is there any possibility for a force-closed on the client side? Or is the
> only possibility to open a new connection without closing the old one, and
> "let it die"?
>
> Re-writing the SocketFrameHandler would of course also be a  possibility,
> but one we would (if possible) like to avoid. (see also discussion here :
> https://github.com/rabbitmq/rabbitmq-java-client/issues/11)
>
>
> Additionally, when we see blocking connections occurring, we frequently
> see following stack trace in our logs, where we are not absolutely sure
> where it comes from, or rather why it occurs
>
>  com.rabbitmq.client.ShutdownSignalException: connection error; reason:
> java.io.EOFException
>
> at com.rabbitmq.utility.ValueOrException.getValue(ValueOrException.java:67)
>
> at
> com.rabbitmq.utility.BlockingValueOrException.uninterruptibleGetValue(BlockingValueOrException.java:37)
>
> at
> com.rabbitmq.client.impl.AMQChannel$BlockingRpcContinuation.getReply(AMQChannel.java:349)
>
> at com.rabbitmq.client.impl.ChannelN.close(ChannelN.java:569)
>
> at com.rabbitmq.client.impl.ChannelN.close(ChannelN.java:501)
>
> ...
>
> Caused by: java.io.EOFException
>
> at com.rabbitmq.client.impl.ChannelN.close(ChannelN.java:494)at
> java.io.DataInputStream.readUnsignedByte(Unknown Source)
>
> at com.rabbitmq.client.impl.Frame.readFrom(Frame.java:95)
>
> at
> com.rabbitmq.client.impl.SocketFrameHandler.readFrame(SocketFrameHandler.java:131)
>
> at
> com.rabbitmq.client.impl.AMQConnection$MainLoop.run(AMQConnection.java:515)
>
>
> For information, we are currently using Java client,
> com.rabbitmq:amqp-client version 3.1.4
>
> and com.zanox.lib.rabbiteasy version:rabbiteasy-core version 1.2.0, for
> the connection handling (SingleConnectionFactory) and publishing.
>
> Thanks in advance for any hint or ideas.
>
> Regards
>
> Claire
>
>
>
>
>



-- 


*Claire Fautsch*
Server Developer
cfautsch at goodgamestudios.com

Goodgame Studios
Theodorstr. 42-90, House 9
22761 Hamburg, Germany
Phone: +49 (0)40 219 880 -0

*www.goodgamestudios.com <http://www.goodgamestudios.com>*


Goodgame Studios is a branch of Altigi GmbH
Altigi GmbH, District court Hamburg, HRB 99869
Board of directors: Dr. Kai Wawrzinek, Dr. Christian Wawrzinek, Fabian
Ritter
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