[rabbitmq-discuss] Statistics database could not be contacted. Message rates and queue lengths will not be shown.

[Simon MacMullen]

Certainly if the stats DB is not around you won't see message counts - 
that's its purpose.

It's certainly not *intended* that a network partition lead to the stats 
DB going away. It's possible we could do better in this case, but we 
store the current location of the stats DB in a distributed DB so you 
can imagine how partitioning would lead to problems. I don't want to 
spend too much time on this since clusters are not designed for 
unreliable networks anyway.

Cheers, Simon

On 05/10/2012 5:13PM, Matt Pietrek wrote:
>
>  > We really don't recommend use of clusters on networks that may be
> subject to partitions.
>
> A follow up question then. We run our brokers in clusters, and hopefully
> nothing ever goes down, we never have network partitions, etc... (and in
> fact, we've had clusters running for months at a time without issue.)
>
> The question is, in the unfortunate event of a network partition, should
> we just expect to lose the capability of the statistics database? It's
> important for us to know, as I've written additional tooling that uses
> the HTTP API to manipulate various things, and when the stats database
> isn't available, various fields returned by the HTTP APIs (like message
> counts) seem to vanish.
>
> Thanks,
>
> Matt
>
> On Fri, Oct 5, 2012 at 3:21 AM, Simon MacMullen <simon at rabbitmq.com
> <mailto:simon at rabbitmq.com>> wrote:
>
>     Hmm. I see various messages about network partitions in the logs;
>     that's not encouraging. We really don't recommend use of clusters on
>     networks that may be subject to partitions. I suspect that may be
>     the root of the problem.
>
>     Cheers, Simon
>
>
>     On 04/10/12 10:36, Wong Kam Hoong wrote:
>
>         Hi Simon,
>
>         The RabbitMQ was clustered (3 RabbitMQs), attached are the full
>         log. The
>         problem happened in between 3-Oct to 4-Oct, I upgraded RabbitMQ to
>         v2.8.7 on 3-Oct.
>
>         Thanks & Regards,
>         Wong
>
>
>         On Thu, Oct 4, 2012 at 5:27 PM, Simon MacMullen
>         <simon at rabbitmq.com <mailto:simon at rabbitmq.com>
>         <mailto:simon at rabbitmq.com <mailto:simon at rabbitmq.com>>> wrote:
>
>              Hi. There's no good set of circumstances to see that
>         message - the
>              stats db should be restarted if it fails. Is this clustered or
>              standalone? Can you post logs?
>
>              Cheers, Simon
>
>
>              On 03/10/12 22:56, Wong Kam Hoong wrote:
>
>                  Hi RabbitMQ  team,
>
>                  Recently I upgrade my rabbitmq nodes with the latest
>         version
>                  2.8.7, but
>                  i saw weird message show on the web admin page:
>
>                  "Statistics database could not be contacted. Message
>         rates and queue
>                  lengths will not be shown."
>
>                  I not able to see any statistic such as current
>         produce/consume
>                  rate,
>                  and how many messages in each queue.
>
>                  Please advise how can i enable back the statistic.
>
>                  Regards,
>                  Wong
>
>
>
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>
>              --
>              Simon MacMullen
>              RabbitMQ, VMware
>
>
>
>
>     --
>     Simon MacMullen
>     RabbitMQ, VMware
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