On Friday 30 January 2015 01:01:00 Boris Bobrov wrote: > On Thursday 29 January 2015 22:06:25 Morgan Fainberg wrote: > > I’d like to propose we stop setting the expectation that a downwards > > migration is a “good idea” or even something we should really support. > > Offering upwards-only migrations would also simplify the migrations in > > general. This downward migration path is also somewhat broken by the > > migration collapses performed in a number of projects (to limit the > > number of migrations that need to be updated when we change a key > > component such as oslo.db or SQL-Alchemy Migrate to Alembic). > > > > Are downward migrations really a good idea for us to support? Is this > > downward migration path a sane expectation? In the real world, would any > > one really trust the data after migrating downwards? > > Frankly, I don't see a case when a downgrade from n to (n - 1) in > development cannot be replaced with a set of fixtures and upgrade from 0 > to (n - 1). > > If we assume that upgrade can possible break something in production, we > should not rely on fixing by downgrading the schema, because a) the code > depends on the latest schema and b) "break" can be different and > unrecoverable. > > IMO downward migrations should be disabled. We could make a survey though, > maybe someone has a story of using them in the fields.
I've made a little survey and there are people who used downgrades for debugging of different OpenStack releases. So, I think I'm +1 on Mike Bayer's opinion. -- Best regards, Boris Bobrov __________________________________________________________________________ OpenStack Development Mailing List (not for usage questions) Unsubscribe: openstack-dev-requ...@lists.openstack.org?subject:unsubscribe http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev
