[Maas-devel] Race in Node.acquire()?

[Raphaël Badin]

On 04/30/2014 04:50 AM, Julian Edwards wrote:
> See https://bugs.launchpad.net/maas/+bug/1314409
>
> Unless I am way off with my analysis, it looks like two "acquire()"
> operations from separate clients got allocated the same Node.
>
> I am left wondering if this is anything to do with Django's useless
> default DB isolation level?

Although AFAIK Django doesn't support optimistic locking, there is 
support —since Django 1.4— for pessimistic locking which I think is what 
we should be explicitly using here to protect such a critical code path 
(https://docs.djangoproject.com/en/dev/ref/models/querysets/#select-for-update).

R.