Admin inlines very slow to render

[Marc DEBUREAUX]

When using inlines in Django admin, it renders very poorly even when creating a new element (so no data to load, database time always the same).

And the higher the number in "extra" parameter, the longer it takes to load the form.

class EffectModifierInline(admin.TabularInline):
    model = EffectModifier
    extra = 1


@admin.register(Effect)
class EffectAdmin(admin.ModelAdmin):
    fieldsets = (
        # Whatever
    )
    inlines = [EffectModifierInline]
    # TODO:
    list_display = ()
    list_editable = ()
    list_filter = ()

    def get_queryset(self, request):
        return super().get_queryset(request).prefetch_related('modifiers')

With 15 inlines

With only 1 inline

With no inline