#28704: update_or_create() calls select_for_update(), which locks database row -------------------------------------+------------------------------------- Reporter: Rafal Radulski | Owner: nobody Type: Bug | Status: new Component: Database layer | Version: 1.11 (models, ORM) | Severity: Normal | Resolution: Keywords: | Triage Stage: | Unreviewed Has patch: 0 | Needs documentation: 0 Needs tests: 0 | Patch needs improvement: 0 Easy pickings: 0 | UI/UX: 0 -------------------------------------+-------------------------------------
Comment (by Tomer Chachamu): I'm assuming you're passing something in `defaults`, right? `update_or_create` currently calls `Model.save` and you are suggesting it should call `QuerySet.update` instead. Both of them send `UPDATE` SQL statements to the database. That will create a row-level lock. In Postgres, the lock level is either `FOR UPDATE` or `FOR NO KEY UPDATE`, see https://www.postgresql.org/docs/9.6/static/explicit-locking.html #LOCKING-ROWS. But, neither of these locks will block an ordinary `SELECT` statement like the `.get()` in the second transaction. -- Ticket URL: <https://code.djangoproject.com/ticket/28704#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 post to this group, send email to django-updates@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/django-updates/064.aee5534d6e5d7c5dd494a72b1a25436a%40djangoproject.com. For more options, visit https://groups.google.com/d/optout.