Django Rest Framework + psycopg2：InterfaceError：游标已关闭

Question

我对 psycopg2 有疑问。它无法执行某些查询。我跟踪了异常，它说：django.db.utils.InterfaceError: cursor already closed

我已经在网上看到过一些类似的案例，尝试了所有的建议，但没有运气。

我使用 Django Rest Framework，在请求某些端点时会导致错误，只是在某些请求中。我监控了 error.log 文件，我看到 15-20 个请求因 HTTP 500 错误而失败。
这个问题有解决办法吗？

软件版本：
djangorestframework == 3.12.1
django == 3.0.5
Python 3.8

这是我在服务器上运行的uswgi.ini 文件。 Socket 被 NGINX 使用。

[uwsgi]

project = DjangoProject
base = /opt/django-project

chdir = %(base)
module = %(project).wsgi:application
home = %(base)/venv

gid = www-data
uid = www-data

master = true
processes = 5
socket = /tmp/%(project).sock
chmod-socket = 664
vacuum = true
harakiri = 60
max-requests = 10000

我试图通过增加与 Postgresql 的连接来解决问题。但没有改变，错误仍然存​​在。 来自postgresql.conf 文件的片段：

max_connections = 2000
shared_buffers = 800MB

完整的堆栈跟踪：

Internal Server Error: /api/users/
Traceback (most recent call last):
  File "/opt/django-project/venv/lib/python3.8/site-packages/django/db/utils.py", line 97, in inner
    return func(*args, **kwargs)
psycopg2.InterfaceError: cursor already closed

The above exception was the direct cause of the following exception:
Traceback (most recent call last):
  File "/opt/django-project/venv/lib/python3.8/site-packages/django/core/handlers/exception.py", line 34, in inner
    response = get_response(request)
  File "/opt/django-project/venv/lib/python3.8/site-packages/django/core/handlers/base.py", line 115, in _get_response
    response = self.process_exception_by_middleware(e, request)
  File "/opt/django-project/venv/lib/python3.8/site-packages/django/core/handlers/base.py", line 113, in _get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
  File "/opt/django-project/venv/lib/python3.8/site-packages/django/views/decorators/csrf.py", line 54, in wrapped_view
    return view_func(*args, **kwargs)
  File "/opt/django-project/venv/lib/python3.8/site-packages/rest_framework/viewsets.py", line 125, in view
    return self.dispatch(request, *args, **kwargs)
  File "/opt/django-project/venv/lib/python3.8/site-packages/rest_framework/views.py", line 509, in dispatch
    response = self.handle_exception(exc)
  File "/opt/django-project/venv/lib/python3.8/site-packages/rest_framework/views.py", line 469, in handle_exception
    self.raise_uncaught_exception(exc)
  File "/opt/django-project/venv/lib/python3.8/site-packages/rest_framework/views.py", line 480, in raise_uncaught_exception
    raise exc
  File "/opt/django-project/venv/lib/python3.8/site-packages/rest_framework/views.py", line 497, in dispatch
    self.initial(request, *args, **kwargs)
  File "/opt/django-project/venv/lib/python3.8/site-packages/rest_framework/views.py", line 414, in initial
    self.perform_authentication(request)
  File "/opt/django-project/venv/lib/python3.8/site-packages/rest_framework/views.py", line 324, in perform_authentication
    request.user
  File "/opt/django-project/venv/lib/python3.8/site-packages/rest_framework/request.py", line 227, in user
    self._authenticate()
  File "/opt/django-project/venv/lib/python3.8/site-packages/rest_framework/request.py", line 380, in _authenticate
    user_auth_tuple = authenticator.authenticate(self)
  File "/opt/django-project/venv/lib/python3.8/site-packages/rest_framework/authentication.py", line 193, in authenticate
    return self.authenticate_credentials(token)
  File "/opt/django-project/venv/lib/python3.8/site-packages/rest_framework/authentication.py", line 198, in authenticate_credentials
    token = model.objects.select_related('user').get(key=key)
  File "/opt/django-project/venv/lib/python3.8/site-packages/django/db/models/query.py", line 411, in get
    num = len(clone)
File "/opt/django-project/venv/lib/python3.8/site-packages/django/db/models/query.py", line 258, in __len__
    self._fetch_all()
  File "/opt/django-project/venv/lib/python3.8/site-packages/django/db/models/query.py", line 1261, in _fetch_all
    self._result_cache = list(self._iterable_class(self))
  File "/opt/django-project/venv/lib/python3.8/site-packages/django/db/models/query.py", line 57, in __iter__
    results = compiler.execute_sql(chunked_fetch=self.chunked_fetch, chunk_size=self.chunk_size)
  File "/opt/django-project/venv/lib/python3.8/site-packages/django/db/models/sql/compiler.py", line 1184, in execute_sql
    return list(result)
  File "/opt/django-project/venv/lib/python3.8/site-packages/django/db/models/sql/compiler.py", line 1583, in cursor_iter
    for rows in iter((lambda: cursor.fetchmany(itersize)), sentinel):
  File "/opt/django-project/venv/lib/python3.8/site-packages/django/db/models/sql/compiler.py", line 1583, in <lambda>
    for rows in iter((lambda: cursor.fetchmany(itersize)), sentinel):
  File "/opt/django-project/venv/lib/python3.8/site-packages/django/db/utils.py", line 97, in inner
    return func(*args, **kwargs)
  File "/opt/django-project/venv/lib/python3.8/site-packages/django/db/utils.py", line 90, in __exit__
    raise dj_exc_value.with_traceback(traceback) from exc_value
  File "/opt/django-project/venv/lib/python3.8/site-packages/django/db/utils.py", line 97, in inner
    return func(*args, **kwargs)
django.db.utils.InterfaceError: cursor already closed

Answer 1

这很可能是由客户端关闭连接引起的。详细解释见https://forum.djangoproject.com/t/db-connection-closed-by-uwsgi-in-the-middle-of-handling-a-request/9875。