[rabbitmq-discuss] Why default connection heartbeat = 0?

[stone]

Thanks!

On Wed, Mar 28, 2012 at 2:48 PM, Emile Joubert <emile at rabbitmq.com> wrote:

> Hi,
>
> On 28/03/12 13:05, stone wrote:
> > One more question, what could possibly be impacted if the default
> > heartbeat value is set to 2, 3 or 5 etc. ?
>
> There is a trade-off. More frequent heartbeats incur greater network and
> CPU overhead but detect network conditions earlier. Lower frequencies
> incur less overhead but are slower to detect network problems. You
> should set the value appropriately for you environment.
>
>
> In answer to your previous question, some reasons for the current
> default have come to light. In previous versions of RabbitMQ (before
> v1.7.0) the heartbeat was set to a non-zero value and this caused these
> problems:
>
> On busy machines the heartbeats would not be generated quickly enough
> and this lead to dropped connections and poor performance.
>
> One machines with thousands of connections the effort of generating
> heartbeats would consume all the CPU resources.
>
> On brokers that have no activity the heartbeats would prevent paging to
> disk and even Erlang hibernation.
>
>
>
> -Emile
>
>
>
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