| Table of Contents |
|---|
...
If you still think you need to change old migrations, and you want to verify that there isn't an alternative, see the "When in doubt" section.
Also, if you absolutely must change old migrations (this includes things like squashing), after merging and verifying your migration changes, you should update the sql that is used to populate devstack during provisioning. This is to prevent conflicts during provisioning in the future. To update the sql, in the devstack repository, run .update-dbs-init-sql-scripts.sh . This should update edxapp.sql, edxapp_csmh.sql, and ecommerce.sql. Create a PR with the updated sql and merge to devstack as usual.
Don't change the parent of a migration
...
When using AWS Aurora, a nullable column can be added to existing large (100k rows+?) tables without causing downtime. However, the migration may still timeout in GoCD - so please coordinate the release with DevOps.
- Make a new field addition in model with null=True.
- Generate the model-change migrations locally.
- Create a pull request containing the model change and newly-generated migrations.
- Merge the migration pull request.
- The release process will run the migration and add the nullable column to table.
...
On AWS Aurora, indexes can be build on large tables without causing downtime, but this requires devops coordination as the migration may timeout in GoCD.
- Add the new index on model fields.
- Generate the model-change migrations locally.
- Make pull request containing the model change and newly-generated migrations.
- Merge the migration pull request.
- Release will run the migration and add the index to table.
...