#32838: Migrations create extra index when foreign key is also part of a unique constraint -------------------------------------+------------------------------------- Reporter: Lev | Owner: nobody Type: | Status: closed Cleanup/optimization | Component: Database layer | Version: 3.2 (models, ORM) | Severity: Normal | Resolution: wontfix Keywords: | Triage Stage: postgres,indexes,unique | Unreviewed constraint,foreign keys | Has patch: 0 | Needs documentation: 0 Needs tests: 0 | Patch needs improvement: 0 Easy pickings: 0 | UI/UX: 0 -------------------------------------+------------------------------------- Changes (by Mariusz Felisiak):
* status: new => closed * resolution: => wontfix Comment: Thanks for this ticket, however it is a [https://docs.djangoproject.com/en/3.2/ref/models/fields/#foreignkey documented] behavior. It's also documented how to disable `ForeignKey` indexes if you want to avoid the overhead: ''A database index is automatically created on the `ForeignKey`. You can disable this by setting `db_index` to `False`. You may want to avoid the overhead of an index if you are creating a foreign key for consistency rather than joins, or if you will be creating an alternative index like a partial or **multiple column index**.'' There are also valid cases for a separate index (see [https://code.djangoproject.com/ticket/22125#comment:17 comment]). IMO we shouldn't break this. You can raise the idea on the DevelopersMailingList to reach a wider audience and see what other think. We can re-open this ticket if we reach consensus on the mailing list. -- Ticket URL: <https://code.djangoproject.com/ticket/32838#comment:1> Django <https://code.djangoproject.com/> The Web framework for perfectionists with deadlines. -- You received this message because you are subscribed to the Google Groups "Django updates" group. To unsubscribe from this group and stop receiving emails from it, send an email to django-updates+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/django-updates/063.a87874d81086371aac869f8d37120612%40djangoproject.com.