[rabbitmq-discuss] hanging on message sending with py-amqplib
tsuraan at gmail.com
Fri Oct 1 23:05:07 BST 2010
> For the archives, setting a prefetch message count limit of 1,000 is
> allowing my other agents to proceed. I'm concerned that there is
> might be a starvation condition inside of rabbit, but the throttling
> does seem to keep it from manifesting.
Nevermind that, it solved one case of hanging, but I have another on a
totally idle machine where all my tx_commit calls are hanging. There
is no disk activity at all; the system is just stuck with a small
handful of processes (consumers/producers) stuck at tx_commit. I can
restart the processes, and they run until their first tx_commit, and
then hang. top shows no CPU activity, and iotop shows no disk
activity. This is also with rabbit 2.1.0 and erlang 13B4.
A sample python script that's hanging for me is:
>>> from amqplib.client_0_8 import Message
>>> ch.basic_publish(m, 'amq.direct', 'foo')
The tx_commit call just never returns. There isn't anything
apparently consuming from any queue, as the disks are entirely idle,
so I don't know what's going on here. I have full shell access to
this machine, so any commands that you can think of that could be done
through remsh, I'd be happy to try. I don't know if I can get you
guys direct access to the machine, but I can try if you need me to.
I have a total of 13 queues, most of which are pretty close to empty.
One of them has ~50,000 and another has ~600,000 messages. All are
durable, and all messages are persistent. The huge queue's consumer
is completely disabled right now, so its consumer isn't generating any
traffic of any kind.
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