[openstack-dev] [nova][keystone] Message Queue Security

Simo Sorce simo at redhat.com
Thu Apr 25 16:27:00 UTC 2013

On Thu, 2013-04-25 at 17:19 +0100, David Chadwick wrote:
> What happens in a very fast system if two sub-processes create a message 
> at the same time and therefore contain the same timestamp?

Well, right now we use eventlet so no concurrency is really allowed.
If we move to a truly concurrent system (something I actually hope we
do) then we'll have to serialize how we get the timestamp. We'll
basically need a single source of time that will just increment by one
hundredth of a second or so if a second request comes in within the same
hundredth of a second. Basically keep a high watermark in shared memory
and use atomic updates to never get a dup.


Simo Sorce * Red Hat, Inc * New York

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