Open Stack

> > >> From: "Doug Hellmann" < doug.hellmann at dreamhost.com >
> > >> To: "OpenStack Development Mailing List"
> > >> < openstack-dev at lists.openstack.org >
> > >> Sent: Wednesday, February 27, 2013 12:21:14 PM
> > >> Subject: Re: [openstack-dev] [keystone] re-ordering of schema
> > >> migrations
> > >> 
> > >> On Wed, Feb 27, 2013 at 9:59 AM, Dan Prince < dprince at redhat.com
> > >> >
> > >> wrote:
> > >> 
> > 
> > >> 
> > >> Yeah. Let's not do that, though. Let's just add new migrations
> > >> as
> > >> necessary. That way each migration is tested, and after it is
> > >> known
> > >> to work
> > >> it is not changed to something different that has to be
> > >> re-tested.
> > > 
> > > 
> > > I don't think Keystone has reached this point either. At some
> > > point
> > > though the number or migrations becomes unwieldy and compacting
> > > things may make more sense though.
> > 
> > And to clarify, we have already done this a couple of times for
> > nova:
> > once for Folsom and again for Grizzly. In Grizzly we're up to 159,
> > but the migrate repo starts with a single migration to get up to
> > 133.
> 
> Yeah, so I mentioned this nova practice of consolidating adjacent
> migrations around major releases, as an acceptable change.
> 
> However, if I understood Doug correctly, he's raising this approach
> as
> a potential issue that should be discontinued.
> 
> Doug - just to clarify, it's not the compaction per se that's
> potentially
> problematic for trunk-chasers, more the risk that in manually
> compacting
> multiple scripts some regression will creep in due to human error?
> 
> 
> 
> Yes. There's no real runtime benefit (the migration framework skips
> the steps it doesn't need to perform) and there's a risk of having
> the results of the micro-migrations be different than the bulk
> migrations, which would make following trunk across a release more
> difficult.


Thanks for the confirmation Doug.

AFAIK this compaction practice is only followed in nova, as the
other projects don't have anything like the same level of proliferation
of migrations. Nova has followed this practice for two release cycles
IIRC, so it would probably take a call from the PTL to discontinue it.

Vish - any thoughts on that?

Cheers,
Eoghan