[rabbitmq-discuss] TCP timeouts

Wed May 7 12:31:48 BST 2008

Hi,

I've run into a problem testing RabbitMQ. My Java clients keep
disconnecting when using a lot of CPU and the error in the RabbitMQ logs
is:
=ERROR REPORT==== 7-May-2008::11:41:44 ===
error on TCP connection from 127.0.0.1:37299
{timeout,frame_header}

I'm using channel.basicGet and I think I've narrowed down the problem. When
I get a message I process it, then call basicAck once it's done. So the
code looks like:
GetResponse basicGet = channel.basicGet(ticket, queueName, false);
 if (basicGet != null) {
        process(basicGet);
        channel.basicAck(basicGet.getEnvelope().getDeliveryTag(), false);
}

if process() looks like this:
            long start = System.currentTimeMillis();
            while(true) {
                long now = System.currentTimeMillis();
                if(now - start > 10000) {
                    break;
                }
            }
The client will disconnect. If I add a Thread.sleep(0) into the loop it
will work fine. The sleep 0 just yields. In my real code it doesn't do that
loop but does do a lot of maths that can take up to about 1 minute so it
has the same effect of killing the CPU for a while.

I guess what's happening is that the connection thread isn't getting any
time to send heartbeats and the server is disconnecting it. Is there a work
around for this? Can I change the heartbeat?

A little more information if that helps:
 - Quad core machine, only using 1 cpu during this test
 - 4GB Ram
 - Erlang 5.5.5 (64bit)
 - Ubunut 64
 - Rabbit mq 1.3.0-1

Thanks,

Dave

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