[rabbitmq-discuss] Often failed to produce message due to TIMEOUT WAITING FOR ACK

Wed Oct 3 05:24:58 BST 2012

Hi Matthias,

Thanks for your advise, after I set the timeout to 1 minute the problem
gone, but 1 minute seems too long..

Regards,
Wong

On Wed, Sep 26, 2012 at 3:17 PM, Matthias Radestock
<matthias at rabbitmq.com>wrote:

> Wong,
>
> On 26/09/12 07:18, Wong Kam Hoong wrote:
>
>> *_Master Node Usage_*
>>
>> Memory : 300M
>> CPU %  : Average 30%
>>
>> _*Slave Node Usage*_
>>
>> Memory : 130M
>> CPU %  : Average 30%
>>
>> there are only few messages during that time, e.g.
>> 2012-09-26 03:28:32 => 4 messages
>>
>
> If the CPU is averaging 30% when the load is so low then the machines must
> be doing something else too. I notice from...
>
>  =INFO REPORT==== 26-Sep-2012::03:29:37 ===
>> accepting AMQP connection <0.8897.18> (192.168.0.100:43836
>> <http://192.168.0.100:43836/> -> 192.168.0.100:5672
>> <http://192.168.0.100:5672/>)
>>
>
> ...that your clients are on the same machine as one of the nodes. Could it
> be that the machine was busy with other tasks, such as your application?
>
> Also, 3:29 in the morning is just the sort of time that I'd expect systems
> to run various housekeeping tasks which could hammer the CPU or disk. Those
> can result in significant delays, particularly when your messages
> persistent.
>
> I recommend increasing the timeout substantially, e.g. to 1 minute. That
> way if the problem really is just due to load it will go away.
>
>
>  Are you using mirrored/HA queues at all?
>> Yes, I'm using HA in all queues.
>>
>
> We are aware of two bugs in 2.8.x that can cause confirms to go missing.
> One of them involved setting an x-message-ttl=0 on queues and use of the
> 'immediate' flag on publish. So if you are doing that then, well, don't :).
> The 2nd issue involves (re)starting of nodes. So check whether any of the
> nodes in your cluster (re)started around the time of the problem.
>
> Regards,
>
> Matthias.
>
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