mild oyster
I renamed the name of a model field. I have about 10 million rows in the Postgres table for this model. This field is part of a unique_together constraint, so my migration includes a AlterUniqueTogether.
I'm wondering -- what are the performance implications of this? Will it delete the existing PG index and create a new one, or simply rename the existing index?
cunning mesa
You can use python manage.py sqlmigrate <app> <migration number> to view the SQL that will be executed for a migration.
The rename operation will likely lock the table while it completes. The unique constraint change should lock the table for inserts and updates until it's validated the table.
Looks like renaming shouldn't lock anything, I was wrong.