[cinder] need comments TODAY about DB handling for default_types
There's a discussion going on about
https://review.opendev.org/#/c/737707/23 , namely about how to handle
the new default_types table. My view is that since it simply records a
relation between a project and a volume_type, it's not the kind of thing
that we need to keep a history of, and entries could be hard-deleted.
The current patch keeps a history by introducing an additional is_active
column. The additional complexity is worth it if we want to keep a
history of this relation, but is not if we don't.
Please leave your thoughts on the patch as soon as possible (i.e., in
the next few hours) so Rajat can complete this feature.