On May 12, 10:04 am, Will McGugan <willmcgu...@gmail.com> wrote: > Hi, > > I recently tracked down a strange bug in our site where 2 object existed but > the code was expecting only one. > > I think this is due to get_or_create, which doesn't appear to be atomic. > What I assume happened is that two requests came in close together and > tested for the existence of the object I was creating. Both requests > detected that the object didn't exist and went on to create a new one. > > Could this be the case? And if so, should I not expect 'get_or_create' to be > an atomic operation? > > Regards, > > Will McGugan >
No, it's not atomic. You can see the code in django.db.models.query - it tries a db lookup, and then creates a new object if one is not found. If your code needs to assume that only one element with a certain combination of values exists, it may be that you need to define unique_together in your model's Meta class (and add the relevant constraints to your db, since your table already exists). -- DR. --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Django users" group. To post to this group, send email to django-users@googlegroups.com To unsubscribe from this group, send email to django-users+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/django-users?hl=en -~----------~----~----~----~------~----~------~--~---
