[openstack-dev] [keystone] sqlite doesn't support migrations

Boris Pavlovic boris at pavlovic.me
Sun Jul 14 17:29:23 UTC 2013

Hi Dolph,

Yes, I agree that there are some problems with sqlite and migrations.
But I am not agree with approach of fully removing sqlite.

It is pretty useful for testing.

So the right approach that we are trying to provide in whole OpenStack is

1) Use alembic as migration tool (don't support sqlite in migrations)
2) Test migrations in two ways:
a) run all migrations with real data against supported backends (mysql,
b) test that models and migrations are synced in all backends (mysql, psql)
3) Unit tests should be run against DB that was created from models (not
from migrations)
4) Unit tests should support all backends (sqlite also)

If you are interested in this sphere I could try to describe current state
in more words.

Best regards,
Boris Pavlovic

On Sat, Jul 13, 2013 at 12:19 AM, Monty Taylor <mordred at inaugust.com> wrote:

> On 07/11/2013 01:12 PM, Dolph Mathews wrote:
> > Just as a general statement, outside the scope of openstack, I don't
> > think sqlite is intended to support schema evolution. From the sqlite
> > docs [1]: "SQLite supports a limited subset of ALTER TABLE. [...] It is
> > not possible to rename a column, remove a column, or add or remove
> > constraints from a table."
> >
> > We've been through hell trying to support migrations on sqlite, because
> > we test against sqlite, and because we test our migrations... on sqlite.
> > So, we've already shot ourselves in the foot. We're clearly moving
> > towards gating against mysql + postgresql, so in the mean time, let's
> > limit the amount of effort we put into further support sqlite migrations
> > until we can safely rip it out altogether.
> >
> > [1]: http://www.sqlite.org/lang_altertable.html
> I agree. The reason to use sqlite in unitests and stuff is because it's
> easy and doesn't require users and system things and everything. If
> we're spending extra effort to maintain the simple thing, then it's
> probably not a simple thing.
> As an aside, (ignore the fact that I'm a former Drizzle core dev) it
> might be worthwhile taking 30 minutes one day and exploring a drizzle
> database test fixture. One of the things we did in drizzle was make it
> not need any bootstrapping and to work sanely with no config files ...
> so launching a drizzle on a spare port, running database tests against
> it and then deleting it should actually be super simple - and at the
> worst no harder than doing what glance does in their functional tests.
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