[rabbitmq-discuss] Queue consumers are blocked on SocketInputStream.socketRead0

[Nicolas Bosansky]

Hi,

Thanks for your response and sorry for using google groups.

We just have found why we don't get messages anymore from the broker.
Your explanation corresponds exactly to our problem : when Hbase connection
fails, it generates an exception, and in this case, we don't 'ack' nor
'nack/reject' the message.

Now, we nack the message when something wrong occurs and so we get the next
messages from the queue.

Thanks again,
Nicolas


2012/10/19 Tim Watson <tim at rabbitmq.com>

> Hi
>
> Please do not use the google group, as we do not own or subscribe to it.
> Thanks!
>
> In terms of your question, please see my comments inline (below).
>
> On 10/18/2012 04:50 PM, Nicolas Bosansky wrote:
>
>> Hello,
>> We have a rabbitMQ consumer that takes messages from a queue and write
>> them in a HBase store.
>> When HBase connection fails, the consumer get an exception and messages
>> are not acknowledged, that's ok.
>> After a few minutes, the consumer doesn't get messages anymore, even
>> after restarting Hbase.
>>
>>
> Firstly, I don't really understand what you're describing here. What does
> the HBase connection failure have to do with the rabbitmq consumer? Are you
> saying that the HBase connection failure causes an unhandled exception on
> the thread which the consumer is running in? What does this have to do with
> acks - are you saying that your client code does not ack messages which
> arrive that cannot be written to HBase? That's fine, but you ought to
> nack/reject them unless you're hanging on to them deliberately in order to
> deal with them later on. Perhaps this is what is causing the problem?
>
> "If a consumer dies without sending an acknowledgement the AMQP broker
> will redeliver it to another consumer or, if none are available at the
> time, the broker will wait until at least one consumer is registered for
> the same queue before attempting redelivery." - http://www.rabbitmq.com/**
> tutorials/amqp-concepts.html<http://www.rabbitmq.com/tutorials/amqp-concepts.html>
>
> So if you do not ack the messages you've already received *nor*
> nack/reject them, then you're not going to get any more messages until you
> do? Am I missing something here, or are you just not instructing the broker
> that you're ready to continue consuming from the queue (by dealing with the
> messages it has already sent you which need to be ack'ed or rejected)?
>
>  When debugging rabbitMQ client, we have noticed, that it is blocked on
>> the following line: SocketInputStream:129 ( Java build 1.6.0_33-b03)
>> The Frame class is waiting for messages, but the used socket doesn't
>> receive any data anymore.
>> We also notice, that there is no timeout on this socket.
>>
>>
> There isn't meant to be a timeout when reading frames.
>
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