Question

我们正在尝试使用自定义用户模型和行为，但后来我们注意到，当通过Django Admin添加新用户时，即使是默认的Django安装也有问题：

即使在其他Django版本中也会出现问题（在Django 1.8 中尝试过，而在最新版本中使用Django 1.11.3 ）。令人惊讶的是，使用SQLite或PostgreSQL数据库时不会发生此问题。此外，通过$./manage.py createuser添加用户并以编程方式将起作用。通过终端编辑以前创建的admin超级用户等现有用途也可以。组的CRUD机制按预期工作，因此只有Add User视图受到影响。

可能的失败点包括 Django核心（任何版本）， MySQL二进制文件（捆绑在XAMPP for Mac中，也试过各种版本），或者 MySQL-Python 连接器（版本1.2.5）。类似的问题here，使用Django 1.10 和MySQL。

复制步骤：

安装最新的Django版本： $ pip install django
安装Python-MySQL驱动程序： $ pip install MySQL-python
创建一个新项目： $ django-admin.py startproject sandbox
在MySQL中创建一个新数据库并在settings.py
迁移Django应用的模型： $ ./manage.py migrate
创建admin超级用户： $ ./manage.py createsuperuser
运行Django的捆绑服务器： $ ./manage.py runserver
转到http://127.0.0.1:8000/admin/login，然后使用admin超级用户凭据登录。
点击用户'添加按钮。屏幕截图中的附加错误将被触发。

示例数据库查询日志：

Query   SET NAMES utf8
Query   set autocommit=1
Query   SELECT `django_session`.`session_key`, `django_session`.`session_data`, `django_session`.`expire_date` FROM `django_session` WHERE (`django_session`.`session_key` = 'ikql6mk9voxq4g0go9avuvuxxrpvwx9w' AND `django_session`.`expire_date` > '2017-07-10 06:58:15.823513')
Query   SELECT `auth_user`.`id`, `auth_user`.`password`, `auth_user`.`last_login`, `auth_user`.`is_superuser`, `auth_user`.`username`, `auth_user`.`first_name`, `auth_user`.`last_name`, `auth_user`.`email`, `auth_user`.`is_staff`, `auth_user`.`is_active`, `auth_user`.`date_joined` FROM `auth_user` WHERE `auth_user`.`id` = 1
Query   SAVEPOINT `s123145414516736_x1`
Query   RELEASE SAVEPOINT `s123145414516736_x1`
Query   ROLLBACK TO SAVEPOINT `s123145414516736_x1`
Query   rollback
Query   set autocommit=1
Quit

SAVEPOINT ROLLBACK似乎是在SAVEPOINT RELEASE之后完成的，导致SAVEPOINT丢失。基于MySQL's SavePoint docs，自然顺序似乎是ROLLBACK然后RELEASE。

这是Traceback消息。除了用于连接MySQL服务器的数据库配置/凭证外，Django的默认settings.py没有其他更改：

Environment:


Request Method: GET
Request URL: http://127.0.0.1:8000/admin/auth/user/add/

Django Version: 1.11.3
Python Version: 2.7.8
Installed Applications:
['django.contrib.admin',
 'django.contrib.auth',
 'django.contrib.contenttypes',
 'django.contrib.sessions',
 'django.contrib.messages',
 'django.contrib.staticfiles']
Installed Middleware:
['django.middleware.security.SecurityMiddleware',
 'django.contrib.sessions.middleware.SessionMiddleware',
 'django.middleware.common.CommonMiddleware',
 'django.middleware.csrf.CsrfViewMiddleware',
 'django.contrib.auth.middleware.AuthenticationMiddleware',
 'django.contrib.messages.middleware.MessageMiddleware',
 'django.middleware.clickjacking.XFrameOptionsMiddleware']



Traceback:

File "/Users/ranelpadon/.virtualenvs/django__1_11/lib/python2.7/site-packages/django/core/handlers/exception.py" in inner
  41.             response = get_response(request)

File "/Users/ranelpadon/.virtualenvs/django__1_11/lib/python2.7/site-packages/django/core/handlers/base.py" in _get_response
  187.                 response = self.process_exception_by_middleware(e, request)

File "/Users/ranelpadon/.virtualenvs/django__1_11/lib/python2.7/site-packages/django/core/handlers/base.py" in _get_response
  185.                 response = wrapped_callback(request, *callback_args, **callback_kwargs)

File "/Users/ranelpadon/.virtualenvs/django__1_11/lib/python2.7/site-packages/django/contrib/admin/options.py" in wrapper
  551.                 return self.admin_site.admin_view(view)(*args, **kwargs)

File "/Users/ranelpadon/.virtualenvs/django__1_11/lib/python2.7/site-packages/django/utils/decorators.py" in _wrapped_view
  149.                     response = view_func(request, *args, **kwargs)

File "/Users/ranelpadon/.virtualenvs/django__1_11/lib/python2.7/site-packages/django/views/decorators/cache.py" in _wrapped_view_func
  57.         response = view_func(request, *args, **kwargs)

File "/Users/ranelpadon/.virtualenvs/django__1_11/lib/python2.7/site-packages/django/contrib/admin/sites.py" in inner
  224.             return view(request, *args, **kwargs)

File "/Users/ranelpadon/.virtualenvs/django__1_11/lib/python2.7/site-packages/django/utils/decorators.py" in _wrapper
  67.             return bound_func(*args, **kwargs)

File "/Users/ranelpadon/.virtualenvs/django__1_11/lib/python2.7/site-packages/django/views/decorators/debug.py" in sensitive_post_parameters_wrapper
  76.             return view(request, *args, **kwargs)

File "/Users/ranelpadon/.virtualenvs/django__1_11/lib/python2.7/site-packages/django/utils/decorators.py" in bound_func
  63.                 return func.__get__(self, type(self))(*args2, **kwargs2)

File "/Users/ranelpadon/.virtualenvs/django__1_11/lib/python2.7/site-packages/django/utils/decorators.py" in _wrapper
  67.             return bound_func(*args, **kwargs)

File "/Users/ranelpadon/.virtualenvs/django__1_11/lib/python2.7/site-packages/django/utils/decorators.py" in _wrapped_view
  149.                     response = view_func(request, *args, **kwargs)

File "/Users/ranelpadon/.virtualenvs/django__1_11/lib/python2.7/site-packages/django/utils/decorators.py" in bound_func
  63.                 return func.__get__(self, type(self))(*args2, **kwargs2)

File "/Users/ranelpadon/.virtualenvs/django__1_11/lib/python2.7/site-packages/django/contrib/auth/admin.py" in add_view
  103.             return self._add_view(request, form_url, extra_context)

File "/Users/ranelpadon/.virtualenvs/django__1_11/lib/python2.7/site-packages/django/contrib/auth/admin.py" in _add_view
  131.                                                extra_context)

File "/Users/ranelpadon/.virtualenvs/django__1_11/lib/python2.7/site-packages/django/contrib/admin/options.py" in add_view
  1508.         return self.changeform_view(request, None, form_url, extra_context)

File "/Users/ranelpadon/.virtualenvs/django__1_11/lib/python2.7/site-packages/django/utils/decorators.py" in _wrapper
  67.             return bound_func(*args, **kwargs)

File "/Users/ranelpadon/.virtualenvs/django__1_11/lib/python2.7/site-packages/django/utils/decorators.py" in _wrapped_view
  149.                     response = view_func(request, *args, **kwargs)

File "/Users/ranelpadon/.virtualenvs/django__1_11/lib/python2.7/site-packages/django/utils/decorators.py" in bound_func
  63.                 return func.__get__(self, type(self))(*args2, **kwargs2)

File "/Users/ranelpadon/.virtualenvs/django__1_11/lib/python2.7/site-packages/django/contrib/admin/options.py" in changeform_view
  1408.             return self._changeform_view(request, object_id, form_url, extra_context)

File "/Users/ranelpadon/.virtualenvs/django__1_11/lib/python2.7/site-packages/django/db/transaction.py" in __exit__
  210.                                 connection.savepoint_rollback(sid)

File "/Users/ranelpadon/.virtualenvs/django__1_11/lib/python2.7/site-packages/django/db/backends/base/base.py" in savepoint_rollback
  348.         self._savepoint_rollback(sid)

File "/Users/ranelpadon/.virtualenvs/django__1_11/lib/python2.7/site-packages/django/db/backends/base/base.py" in _savepoint_rollback
  308.             cursor.execute(self.ops.savepoint_rollback_sql(sid))

File "/Users/ranelpadon/.virtualenvs/django__1_11/lib/python2.7/site-packages/django/db/backends/utils.py" in execute
  80.             return super(CursorDebugWrapper, self).execute(sql, params)

File "/Users/ranelpadon/.virtualenvs/django__1_11/lib/python2.7/site-packages/django/db/backends/utils.py" in execute
  65.                 return self.cursor.execute(sql, params)

File "/Users/ranelpadon/.virtualenvs/django__1_11/lib/python2.7/site-packages/django/db/utils.py" in __exit__
  94.                 six.reraise(dj_exc_type, dj_exc_value, traceback)

File "/Users/ranelpadon/.virtualenvs/django__1_11/lib/python2.7/site-packages/django/db/backends/utils.py" in execute
  63.                 return self.cursor.execute(sql)

File "/Users/ranelpadon/.virtualenvs/django__1_11/lib/python2.7/site-packages/django/db/backends/mysql/base.py" in execute
  101.             return self.cursor.execute(query, args)

File "/Users/ranelpadon/.virtualenvs/django__1_11/lib/python2.7/site-packages/MySQLdb/cursors.py" in execute
  205.             self.errorhandler(self, exc, value)

File "/Users/ranelpadon/.virtualenvs/django__1_11/lib/python2.7/site-packages/MySQLdb/connections.py" in defaulterrorhandler
  36.     raise errorclass, errorvalue

Exception Type: OperationalError at /admin/auth/user/add/
Exception Value: (1305, 'SAVEPOINT s123145452511232_x1 does not exist')

Answer 1

这个错误困扰了我很长一段时间，所以我决定进一步挖掘并尝试一劳永逸地解决它。

根本原因：SAVEPOINT问题是仅在MySQL-Python连接器中发生的错误。

修正：使用其他MySQL驱动程序（例如mysqlclient）。

详情/发现：

在Homebrew，MAMP和XAMPP for Mac中尝试过MySQL二进制文件。
尝试了各种MySQL版本，5.6（libmysqlclient.18.dylib）和5.7（libmysqlclient.20.dylib）。
尝试了各种Python的MySQL驱动程序。

通过改变MySQL二进制文件/版本找不到任何关系。但我通过测试Python中常用的各种MySQL驱动程序来缩小问题范围：

MySQLdb （广泛使用但旧的数据库连接器，最后一次提交是7年前！）：

$ pip install MySQL-python
mysqlclient （MySQL-python的现代版本，但有许多错误修复和改进）：

$ pip install mysqlclient
PyMySQL （纯Python MySQL数据库驱动程序）：

$ pip install PyMySQL

然后，添加settings.py（位于import os下方）：
```
try:
    import pymysql
    pymysql.install_as_MySQLdb()
except:
    pass
```
MySQL-Connector-Python （纯Python MySQL数据库驱动程序）：

$ pip install mysql-connector-python-rf

然后，在ENGINE中修改数据库的settings.py配置：
```
'ENGINE': 'mysql.connector.django',
```

SAVEPOINT问题仅在使用 MySQL-python 连接器（＃1驱动程序）时发生，而在其他连接器（＃2，＃3，＃4驱动程序）中不存在。就我而言，我选择了 mysqlclient 。问题现在已经消失。

Answer 2

我通过覆盖 UserAdmin 解决了这个问题。集群数据库中的嵌套原子事务似乎存在问题。

将以下行添加到从基本 Django UserAdmin 继承的自定义 UserAdmin：

@sensitive_post_parameters_m
@csrf_protect_m
def add_view(self, request, form_url='', extra_context=None):
    return self._add_view(request, form_url, extra_context)

Answer 3

我有一个项目刚刚从python 2升级到了3，这是因为我安装了mysqlclient，这就是从上面的建议之一中提取（在python 3.5上）的原因：

$ pip install PyMySQL

in settings.py added:

try:
    import pymysql
    pymysql.install_as_MySQLdb()
except:
    pass

Django + MySQL - 管理员站点 - 添加用户 - 操作错误 - SAVEPOINT不存在

3 个答案: