Django: Using an F expression for a text field in an update call

Question

In a django view, I need to append string data to the end of an existing text column in my database. So, for example, say I have a table named \"ATable\", and it has a fiel

Answer 1

And if you get this running, it isn't thread safe. While your update is running, some other process can update a model not knowing the data in the database is updated.

You have too acquire a lock, but don't forget this senario:

1. Django: m = Model.objects.all()[10]
2. Django: m.field = field
3. Django: a progress which takes a while (time.sleep(100))
4. DB: Lock table
5. DB: Update field
6. DD: Unlock table
7. Django: the slow process is finished
8. Django: m.save()

Now the field update became undone by the model instance in Django (Ghost write)