[openstack-dev] [Keystone][Nova] Why migrate_version not InnoDB?

David Ripton dripton at redhat.com
Mon Jul 1 20:24:49 UTC 2013

On 07/01/2013 12:49 PM, Brant Knudson wrote:
> 'Stackers -
> I've got a review up in Keystone that converts tables from MyISAM to
> InnoDB [0], which I patterned after a change in Nova. One of the
> comments in the review is suggesting that the migrate_version table
> should also be changed. The reason I didn't include migrate_version is
> because that's the way Nova did it, but other than that I don't know why
> migrate_version should not be converted. The Nova code is pretty
> explicit that migrate_version isn't changed [1]. Maybe somebody who
> knows MySQL or SQLAlchemy-migrate better than I do can come up with a
> reason why migrate_version shouldn't be changed from MyISAM to InnoDB.
> [0] https://review.openstack.org/#/c/33102/ - Use InnoDB for MySQL
> [1]
> https://github.com/openstack/nova/blob/master/nova/tests/db/test_migrations.py#L331

sqlalchemy-migrate relies on the migrate_versions table, so modifying it 
from within a sqlalchemy-migrate script is scary.  And it's a tiny table 
that's only used during DB migrations, so I doubt you'd see any actual 

David Ripton   Red Hat   dripton at redhat.com

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