Django模型管理器queryset过滤器位于可感知的datetime:在服务器重新启动之前不会显示任何项

I have a Django model which has a publication_date and an is_published fields. I've created a manager for this model which returns all published items which means: every item that has is_published=True and publication_date <= now. I have a Django model which has a publication_d