- uploaded_at = models.DateTimeField(_('creation date'), auto_now_add=True, editable=False)
- extra_info = jsonfield.JSONField(_('extra information'), default='{}', editable=False)
+ uploaded_at = models.DateTimeField(_('creation date'), auto_now_add=True, editable=False, db_index=True)
+ extra_info = jsonfield.JSONField(_('extra information'), default={}, editable=False)