Re: [clojure-rabbitmq] The execution hangs when nested publish inside consumer handler function
I posted the code snippet that can cause the issue on github. Also posted
differences in network trace between blocking and success run that I've
noticed there.
The output from rabbitmqctl eval `rabbitmq_diagnostics:maybe_stuck().` is
Error: {undef,[{rabbitmq_diagnostics,maybe_stuck,[],[]},
{erl_eval,do_apply,6,[{file,erl_eval.erl},{line,657}]},
{rpc,'-handle_call_call/6-fun-0-',5,
[{file,rpc.erl},{line,205}]}]}
On Tuesday, July 21, 2015 at 5:47:44 PM UTC+7, Michael Klishin wrote:
On 21 Jul 2015 at 11:17:50, Nuttanart Pornprasitsakul (visib...@gmail.com
javascript:) wrote:
Follow up from the issue #74 I created on Github(
https://github.com/michaelklishin/langohr/issues/74).
Sorry that I posted there.
It doesn't eventually unblock, both in and out queue are in idle
state not flow state. I'll get back again with the log and thread
dump.
There’s nothing unusual in the thread stack traces. We need a Wireshark
protocol
capture.
rabbitmqctl eval `rabbitmq_diagnostics:maybe_stuck().` output may also
help.
--
MK
Staff Software Engineer, Pivotal/RabbitMQ
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Re: [clojure-rabbitmq] The execution hangs when nested publish inside consumer handler function
On 22 Jul 2015 at 10:46:18, Nuttanart Pornprasitsakul (visiblet...@gmail.com)
wrote:
I posted the code snippet that can cause the issue on github.
Also posted differences in network trace between blocking and
success run that I've noticed there.
Thanks, this is a fairly busy week for me with 3 releases but I will take a look
in the next few days.
The output from rabbitmqctl eval `rabbitmq_diagnostics:maybe_stuck().`
is
Error: {undef,[{rabbitmq_diagnostics,maybe_stuck,[],[]},
{erl_eval,do_apply,6,[{file,erl_eval.erl},{line,657}]},
{rpc,'-handle_call_call/6-fun-0-',5,
[{file,rpc.erl},{line,205}]}]}
This means your version doesn’t have that function (it’s fairly new, I think
3.5.x)
--
MK
Staff Software Engineer, Pivotal/RabbitMQ
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[clojure-rabbitmq] Re: Reusing channel in message handler function
On Wednesday, July 22, 2015 at 12:14:36 PM UTC+3, Nuttanart Pornprasitsakul wrote: Hi, This question is related to blocking issue that I'm asking https://github.com/michaelklishin/langohr/issues/74, but I think better separating this to prevent putting more noises in that issue. I started to think that the issue that happens to me causes by opening and closing channel to often in the subscribe handler function (the snippet below extracted from here https://github.com/michaelklishin/langohr/issues/74#issuecomment-123536849 ) (lc/subscribe channel source (fn [ch meta message] (let [pub-ch (lch/open conn)] (lb/publish pub-ch destination (str message)) (lch/close pub-ch)) (lb/ack ch (:delivery-tag meta The reason I keep doing it this way is because in the Java RabbitMQ client Channel documentation https://www.rabbitmq.com/releases/rabbitmq-java-client/current-javadoc/com/rabbitmq/client/Channel.html says that a channel shouldn't be shared between threads. As my understanding, message handler function can be executed in multiple threads that's why I create a new channel and close it within the handler function. But from my other test results, it seems like sharing channel between threads making handler function run a lot faster and importantly, blocking issue doesn't happen. You can reuse the channel in this particular case. Yes, consumer methods will be executed in a thread pool but per-channel ordering is guaranteed by the Java client (ConsumerWorkService, in case you wonder). I didn't realise you were closing and opening channels inside a delivery handler. That should not be necessary and sounds more dangerous than technically having channel sharing ;) Thread sharing is a no-go if you intend to publish on a channel concurrently. As I explained in above, Java client will effectively make publishing sequential in your case. If this solves the blocking issue for you, I'd simply recommend you publish responses on the same channel your deliveries are on (this is why the callback has `ch` as the first argument!) and move on :) MK -- You received this message because you are subscribed to the Google Groups clojure-rabbitmq group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure-rabbitmq+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
