As downgrade are not supported after Kilo, we should remove them now.
Roll backs can be performed as mentioned in the below link:
http://docs.openstack.org/ops-guide/ops-upgrades.html#rolling-back-a-failed-upgrade
The DB downgrades were deprecated in Glance Mitaka release by commit
e3366afdfb.
Change-Id: I937d15d93f16a3e44a50e6ff1a469098eab67c79
Implements: blueprint remove-db-downgrade
Glance SQL scripts assume too much about the environment and the way in
which they are executed by sqlalchemy-migrate. Particularly, they manage
transactions on their own even though sqlalchemy-migrate do it itself,
plus it assumes that scripts are executed in one go (even though
standard Python DB-API 2.0 does not mention multi-statement SQL commands
to be executed on DB cursors.
Also fix comments to be actual SQL comments and not C comments
https://blueprints.launchpad.net/oslo.db/+spec/enable-mysql-connector
Change-Id: I10c58b3af75d3ab9153a8bbd2a539bf1577de328
Closes-Bug: 1368391
Closes-Bug: 1410494
Sqlite doesn't support dropping a column from a table. The
downgrade path for migration 016 performed this. So this commit adds the
sql file to perform the downgrade manually.
Change-Id: I6aae263c3aab03a383c47fd29c46f0cc9b857549
wangxiyuan