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From Alan Conway <acon...@redhat.com>
Subject Re: BDB Message store - rationale?
Date Wed, 23 Dec 2009 13:59:17 GMT
On 12/22/2009 05:50 PM, Rob Springer wrote:
> Hey all - we have run up against the max open files aspect of using the
> message store plugin, and would rather not require our users edit
> limits.conf to be able to run our software (and the fact that we'd just
> be racing against the scaling up of the number of declared queues is
> scary), so we were considering potential alternative solutions.
>
> The first question that came up was regarding the message store plugin's
> use of journal files - why is such a large number (8) the default? Why
> are the queues created per-queue, as opposed to a coarser-grained
> implementation, etc?
>
> Google and mailing list searches didn't reveal a ton of rationale /
> design discussions, so we figured we'd ask directly...
>
> Finally, if this isn't the mailing list to ask this on (is there a Red
> Hat one for the message store?), could y'all direct me there?
>

This is the right list, all the relevant people hang out here but maybe on vacation.

I believe the main reason for per-queue journal files is so the queue can be 
allocated a contiguous block of disk space at the outset which is used as a 
circular buffer, so disk heads dont have to skip around to write successive 
messages on the same queue. On your other questions, I'll defer to the author of 
the store.

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