[rabbitmq-discuss] Problems with RabbitMQ not responding on channel request

Wed Aug 18 22:44:35 BST 2010

Thank you for your reply!

This might be a little question but, if RabbitMQ runs out of memory, and I
am unable to open a new channel, how would one then consume off the queue,
if one isn't able to open a channel to do so? Or is this something which has
been solved with the new persister?

Cheers

Cal

On Wed, Aug 18, 2010 at 5:44 PM, Alexandru Scvorţov
<alexandru at rabbitmq.com>wrote:

> Hi Cal,
>
> > I seem to have a problem where RabbitMQ will stop accepting channel
> requests
> > after either a certain amount of messages are in the queue, or once I
> have
> > sent 200-300 connection requests.
>
> What you describe is usually caused by rabbit running out memory.
>
> When rabbit runs out of memory it stops accepting new connections.
> Check the logs for for warnings about the hitting the high memory
> watermark to see if this is indeed the case.
>
> > At first I thought it was a memory problem, but if I restart RabbitMQ,
> > sometimes it will start accepting connections again and allow me to put
> more
> > items on the queue, but then other times it won't.
>
> Sounds like you're squeezing in a few more messages before hitting the
> memory
> watermark again.
>
> > Currently, I am at 324k messages in the queue.
> > Does anyone have any ideas what could be causing this?
>
> That's sounds like an awful lot of messages.  Do you actually need all
> of them on the queue?  Are you consuming them? (if so, are you also
> ack'ing them?)
>
> The problem you're facing is that the released versions of rabbit hold
> all of the messages in memory.  As a direct consequence, how many
> messages you can hold in the broker is upper-bounded by the amount of
> RAM you have (the default is 0.4 of the available RAM, if I remember
> correctly).  This has been fixed on the default branch (i.e. the amount
> of messages is upper-bounded by disk-space) and will be in the next
> release.
>
> Hope this helps.
>
> Cheers,
> Alex
>

-- 

Cal Leeming

Operational Security & Support Team

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