Make ModelAdmin.list_display only select proper fields

[Mounir]

ModelAdmin list does always select all fields of the model.
When debugging this locally I got some issue when for example the model contain some big text fields.

A workaround of this is to use defer or only on the get_queryset to avoid the huge data to be loaded into the memory and causing the SQL request to take some time, despite explain analyse giving good results.

Would it be an option to enforce the usage of only on list_display to be the same as list_display when defined.

E.g:

class Model(models.Model)
    name = ...
    large_xml_data = ...

@admin.register(Model)
class MyModelAdmin(admin.ModelAdmin):
    list_display = ['id', 'name']

when accessing /admin/models/ this would result into a Model.objects.all().only(*MyModelAdmin.list_display).

[Tim Graham]

The workaround you've identified is the correct solution. We can't be too clever here since list_display can also include model methods, etc.