解决HUE报错MultipleObjectsReturned: get() returned more than one Document2 -- it returned 2!

表现：界面上报错：，刚登陆进去就能看到，点击执行也会出现。日志里报：

Traceback (most recent call last):
  File "/home/work/hue-3.10.0/desktop/libs/notebook/src/notebook/decorators.py", line 81, in decorator
    return func(*args, **kwargs)
  File "/home/work/hue-3.10.0/desktop/libs/notebook/src/notebook/api.py", line 124, in execute
    history = _historify(notebook, request.user)
  File "/home/work/hue-3.10.0/desktop/libs/notebook/src/notebook/api.py", line 319, in _historify
    is_history=True
  File "/home/work/hue-3.10.0/build/env/local/lib/python2.7/site-packages/Django-1.6.10-py2.7.egg/django/db/models/manager.py", line 157, in create
    return self.get_queryset().create(**kwargs)
  File "/home/work/hue-3.10.0/build/env/local/lib/python2.7/site-packages/Django-1.6.10-py2.7.egg/django/db/models/query.py", line 322, in create
    obj.save(force_insert=True, using=self.db)
  File "/home/work/hue-3.10.0/desktop/core/src/desktop/models.py", line 1138, in save
    home_dir = Document2.objects.get_home_directory(self.owner)
  File "/home/work/hue-3.10.0/desktop/core/src/desktop/models.py", line 935, in get_home_directory
    return self.get(owner=user, parent_directory=None, name=Document2.HOME_DIR, type='directory')
  File "/home/work/hue-3.10.0/build/env/local/lib/python2.7/site-packages/Django-1.6.10-py2.7.egg/django/db/models/manager.py", line 151, in get
    return self.get_queryset().get(*args, **kwargs)
  File "/home/work/hue-3.10.0/build/env/local/lib/python2.7/site-packages/Django-1.6.10-py2.7.egg/django/db/models/query.py", line 313, in get
    (self.model._meta.object_name, num))
MultipleObjectsReturned: get() returned more than one Document2 -- it returned 2!

复现步骤：已账号xxxx登录hue，即可看到异常.

ps: 有人在官网报此问题，http://gethue.com/how-to-fix-the-multipleobjectsreturned-error-in-hue/  但官方没有给出解决方法.

根据stacktrace： File "/home/work/hue-3.10.0/desktop/core/src/desktop/models.py", line 935, in get_home_directory查到代码：

  def get_home_directory(self, user):
    try:
      return self.get(owner=user, parent_directory=None, name=Document2.HOME_DIR, type='directory')
    except Document2.DoesNotExist:
      return self.create_user_directories(user)

是class Document2Manager的方法，怀疑是用户表中存的用户记录多了一条，所以查到两个home directory，查了auth_user表和useradmin_userprofile表，都正常。后又查表desktop_document2，按self.get()中的查询条件果然查到两行：

查别的正常账号，只有一条，解决方法应该是删掉多余的数据即可。

由于此表有个自连接的外键：CONSTRAINT `parent_directory_id_refs_id_4fe2babf` FOREIGN KEY (`parent_directory_id`) REFERENCES `desktop_document2` (`id`), 应先删除衍生数据，再删除根数据：

delete from desktop_document2 where parent_directory_id=7;

delete from desktop_document2 where id=7;

之后测试，果然解决。

为何会产生两条数据，原因未知。