[rabbitmq-discuss] Performance Issue

Tue Jan 15 22:14:02 GMT 2013

Pavel,

On 15/01/13 21:56, Pavel Kogan wrote:
> I am playing now with basic.qos setting but I am not seeing 200Hz. I
> see 124Hz which is distributed 100 + 24 and not 62 + 62.

No idea why that would happen. Could be a quirk of the stats reporting 
since evidently you are receiving more acks than messages, which cannot 
possibly be true for anything other than brief periods.

> What is recommended value for prefetch_count for maximal throughput?

As high as possible, though I doubt anything much higher than 100 will 
be beneficial in your case.

The downsides of high prefetch counts are:

- increase in client buffering requirements

- work load imbalance at consumers when work loads are non-uniform

- increased cost at broker when consumer connections are interrupted

Regards,

Matthias.