[rabbitmq-discuss] [help] [beginner] server stops sending messages; publish (in transaction) hangs on commit

Simon MacMullen simon at rabbitmq.com
Thu Feb 23 12:01:18 GMT 2012

On 23/02/12 11:34, Marek Majkowski wrote:
> You seem to have quite a small amount of RAM - 100MiB, right?
> Do logs show high memory watermark being set?

More to the point, the OP's "rabbitmqctl report" output shows memory use 
above the watermark. So yes...

> If so: rabbitmq tries not to go above a memory limit.
> When rabbit hits memory limit it stops consuming messages -

As in, it will block on message publish. In tx mode that equates to a 

> all connections that produce messages will be stopped.
> The connection won't be touched until some memory is freed.
> But in setups where total memory is small, RabbitMQ may
> enter a state of just being above memory watermark and not
> being able to free anything. This may be happening to you.

...and you can set vm_memory_high_watermark higher to work around this. 
See http://www.rabbitmq.com/memory.html.

Cheers, Simon

Simon MacMullen
RabbitMQ, VMware

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