Comment 4 for bug 1800417

Thanks for the comments! Yes, it is rally case and hard to reproduce.
From code level:
in reserve_provider_segment -> allocate_partially_specified_segment, if multiple process/threads call

count = (session.query(self.model).filter_by(allocated=False, **raw_segment). update({"allocated": True}))

concurrently, it may casused the same segment be allocated to differet networks, the code:

alloc = random.choice(allocs)

can help to reduce the possibility, but it still have the possibility for this issue.

We are found the issue with a customized type driver which do not select the segment randomly, Let me try to see whether I can get some logs for you.

And do you know if community had some solution for such issue? Thanks!