No more soft delete

https://blueprints.launchpad.net/nova/+spec/no-more-soft-delete

There was widespread agreement at the YVR summit not to soft-delete any more things. To codify this, we should remove the SoftDeleteMixin from NovaBase.

Problem description

Soft deletion of rows imposes a management overhead to later delete or archive those rows. It has also proved less necessary than initially imagined. We would prefer additional soft-deletes were not added and so it does not make sense to automatically inherit the SoftDeleteMixin when inheriting from NovaBase.

Use Cases

As an operator, adding new soft deleted things means I need to extend my manual cleanup to cover those things. If I don’t, those tables will become very slow to query.

As a developer, I don’t want to tempt operators to read soft-deleted rows directly. That risks turning the DB schema into an unofficial API.

As a developer/DBA, providing deleted and deleted_at columns on tables which are not soft-deleted is confusing. One might also say it’s confusing to soft-delete from tables where deleted rows are never read.

Proposed change

This spec proposes removing the SoftDeleteMixin from NovaBase and re-adding it to all tables which currently inherit from NovaBase. The removal of SoftDeleteMixin from those tables which don’t need it will be left for future work.

Alternatives

We could not do this. This means we need an extra two columns on new tables and it makes it slightly easier to start soft-deleting new tables.

Data model impact

None.

REST API impact

None.

Security impact

None.

Notifications impact

None.

Other end user impact

None.

Performance Impact

None.

Other deployer impact

None.

Developer impact

None.

Implementation

Assignee(s)

Primary assignee:

alexisl

Other contributors:

None

Work Items

• Remove SoftDeleteMixin from NovaBase.

• Add it to all models which inherited from NovaBase.

Dependencies

None.

Testing

None.

Documentation Impact

None.

References

None.

History

Revisions

Release Name	Description
Liberty	Introduced
Mitaka	Simplified and re-proposed