* Mark security_group_instance_associations as deleted when instance deleted * Mark security_group_instance_associations as deleted when security_group deleted * Make SecurityGroup.instances mapping properly ignore deleted security_group_instance_associations * Add tests
IMO, this is important to merge. Nebula has monitoring projects that continually launch and destroy instances, and I imagine other real-world deployments may have similar health checkers. After a few weeks such health checkers choke due to the inefficient queries related to #709057.