Hi Brant, In addition to the race you've fixed in https://review.openstack.org/#/c/50767/, it looks like there are quite a few more races in the SQL backend of keystone.assignment. I filed a bug to this effect: https://bugs.launchpad.net/keystone/+bug/1246489. The general problem is that transactions are used somewhat indiscriminately. The fix (i.e., using transactions judiciously) is straightforward and should be mostly independent of your ongoing oslo.db sessions port in https://review.openstack.org/#/c/49460/. So, unless you already have something in the works, I'll get started on that tomorrow. I'm eager to fix these races so https://review.openstack.org/#/c/42967/ can reliably pass tempest :-) Peter