=============
Upgrade Guide
=============

Database upgrade
----------------

The migrations in ``alembic_migrations/versions`` contain the changes needed to
migrate between Mistral database revisions. A migration occurs by executing a
script that details the changes needed to upgrade the database. The migration
scripts are ordered so that multiple scripts can run sequentially. The scripts
are executed by Mistral's migration wrapper which uses the Alembic library to
manage the migration. Mistral supports migration from Kilo or later.

You can upgrade to the latest database version via:
::

    $ mistral-db-manage --config-file /path/to/mistral.conf upgrade head

You can populate the database with standard actions and workflows:
::

    $ mistral-db-manage --config-file /path/to/mistral.conf populate


To check the current database version:
::

    $ mistral-db-manage --config-file /path/to/mistral.conf current

To create a script to run the migration offline:
::

    $ mistral-db-manage --config-file /path/to/mistral.conf upgrade head --sql

To run the offline migration between specific migration versions:
::

    $ mistral-db-manage --config-file /path/to/mistral.conf upgrade <start version>:<end version> --sql

Upgrade the database incrementally:
::

    $ mistral-db-manage --config-file /path/to/mistral.conf upgrade --delta <# of revs>

Or, upgrade the database to one newer revision:
::

    $ mistral-db-manage --config-file /path/to/mistral.conf upgrade +1

Create new revision:
::

    $ mistral-db-manage --config-file /path/to/mistral.conf revision -m "description of revision" --autogenerate

Create a blank file:
::

    $ mistral-db-manage --config-file /path/to/mistral.conf revision -m "description of revision"

This command does not perform any migrations, it only sets the revision.
Revision may be any existing revision. Use this command carefully.
::

    $ mistral-db-manage --config-file /path/to/mistral.conf stamp <revision>

To verify that the timeline does branch, you can run this command:
::

    $ mistral-db-manage --config-file /path/to/mistral.conf branches

If the migration path has branch, you can find the branch point via:
::

    $ mistral-db-manage --config-file /path/to/mistral.conf history

