[rabbitmq-discuss] High-number of unack-ed messages

Brendan Doyle brendan.doyle at epicadvertising.com
Thu May 13 16:20:06 BST 2010


On 1.7.2 I often see unack count reported by rabbitmqctl much higher than my QoS x number of consumers

I always wrote it off to high throughput and different priorities on handling new incoming messages vs. acks or another internal implementation detail

Brendan

On 2010-05-13, at 9:40 AM, Matthew Sackman wrote:

> Hi Andreas,
> 
> On Thu, May 13, 2010 at 12:02:04PM +0200, Andreas Jung wrote:
>> I inserted some 500k messages with one produce into the queue.
>> Then I attached one consumer to the queue feeding the messages into
>> Solr. The consumer is implemented as callback using the Carrot bindings
>> for Python. Every message is directly acknowledged. However "Alice"
>> always shows me between 300 and 500 unacknowledged messages. Shouldn't
>> that number be 0 or 1?
> 
> Well. It should be low, but if there's no QoS being set by Alice then it
> can get quite high. I would only trust it to be 0 or 1 if Alice was also
> setting a QoS prefetch of 1, and even then, there are cases where the
> unack count can be higher than that.
> 
> After Alice had drained all 500k messages, was the unack count still
> high, or had it dropped to 0 by then?
> 
> Matthew
> 
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