[rabbitmq-discuss] blocked producers

Thu Jul 18 23:19:30 BST 2013

2013/7/19 Kobi Biton <kbiton at outbrain.com>

>  this is to our understanding
> in order to protect the broker and the consumer as the producers are
> faster then the consumer ?
>

Yes, because messages have certain RAM cost.

> The problem is that at some point (when the READY messages count is high ~
> 1M)  rabbitmq blocks most of our producers and does not seem to release
> them , until we restart them (logstash daemon) on every one of them , we
> tried purging the queue / restarting rabbitmq , only restarting the
> producers seems to bring things to normal state.
>

It's driven by memory watermark and/or available disk space. See

http://www.rabbitmq.com/memory.html

RabbitMQ log should make it clear what limit (RAM or disk) was reached.

>
> I guess my questions are:
>
>  - Is my problem on the consumer side ? I am unable to debug the consumer
> speed or state
>

Yes, consumers do not keep up. Try with a larger number of them.

>  - Can I tune rabbitmq for lots of connections and high message rate?
>

It's not really about the number of connections or message rates. See
http://www.rabbitmq.com/memory.html

>  - We use fanout exchange , when a consumer creates a new queue under this
> exchange and does not consume fast enough can he effect the producers from
> the other queue (i.e cause them to be blocked?)
>

All connections that attempt to publish anything when one of the limits is
hit
will be throttled.

You can reduce RAM footprint of individual messages by using
https://github.com/rabbitmq/rabbitmq-toke
which stores message index in Tokyo Cabinet. Yes, it does not even have a
README :(
-- 
MK

http://github.com/michaelklishin
http://twitter.com/michaelklishin
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