Question

我一直在处理这个问题。我设置了一台全新的机器。我已经安装了postgresql和我所有其他依赖项的新副本。基本上，我随机地将这些数据库断开连接。我可以执行相同的请求，无论是有效还是无效。外观非常不确定。在Postgresql上查看日志，它甚至没有连接。现在，我希望如果它从未连接，我会在建立连接和获取光标时遇到此问题，但是我在以后尝试实际使用连接时会得到它。鉴于下面的回溯，我希望看到在pg日志中建立连接，然后由于某种原因断开连接。我没有，所以我想知道是否存在一些不匹配的线索。

Traceback (most recent call last):
  File "/usr/local/lib/python2.6/dist-packages/Django-1.1-py2.6.egg/django/core/handlers/wsgi.py", line 242, in __call__
    response = self.get_response(request)
  File "/usr/local/lib/python2.6/dist-packages/Django-1.1-py2.6.egg/django/core/handlers/base.py", line 73, in get_response
    response = middleware_method(request)
  File "/usr/local/lib/python2.6/dist-packages/Django-1.1-py2.6.egg/django/middleware/locale.py", line 16, in process_request
    language = translation.get_language_from_request(request)
  File "/usr/local/lib/python2.6/dist-packages/Django-1.1-py2.6.egg/django/utils/translation/__init__.py", line 97, in get_language_from_request
    return real_get_language_from_request(request)
  File "/usr/local/lib/python2.6/dist-packages/Django-1.1-py2.6.egg/django/utils/translation/trans_real.py", line 349, in get_language_from_request
    lang_code = request.session.get('django_language', None)
  File "/usr/local/lib/python2.6/dist-packages/Django-1.1-py2.6.egg/django/contrib/sessions/backends/base.py", line 63, in get
    return self._session.get(key, default)
  File "/usr/local/lib/python2.6/dist-packages/Django-1.1-py2.6.egg/django/contrib/sessions/backends/base.py", line 172, in _get_session
    self._session_cache = self.load()
  File "/usr/local/lib/python2.6/dist-packages/Django-1.1-py2.6.egg/django/contrib/sessions/backends/db.py", line 16, in load
    expire_date__gt=datetime.datetime.now()
  File "/usr/local/lib/python2.6/dist-packages/Django-1.1-py2.6.egg/django/db/models/manager.py", line 120, in get
    return self.get_query_set().get(*args, **kwargs)
  File "/usr/local/lib/python2.6/dist-packages/Django-1.1-py2.6.egg/django/db/models/query.py", line 300, in get
    num = len(clone)
  File "/usr/local/lib/python2.6/dist-packages/Django-1.1-py2.6.egg/django/db/models/query.py", line 81, in __len__
    self._result_cache = list(self.iterator())
  File "/usr/local/lib/python2.6/dist-packages/Django-1.1-py2.6.egg/django/db/models/query.py", line 238, in iterator
    for row in self.query.results_iter():
  File "/usr/local/lib/python2.6/dist-packages/Django-1.1-py2.6.egg/django/db/models/sql/query.py", line 287, in results_iter
    for rows in self.execute_sql(MULTI):
  File "/usr/local/lib/python2.6/dist-packages/Django-1.1-py2.6.egg/django/db/models/sql/query.py", line 2369, in execute_sql
    cursor.execute(sql, params)
  File "/usr/local/lib/python2.6/dist-packages/Django-1.1-py2.6.egg/django/db/backends/util.py", line 19, in execute
    return self.cursor.execute(sql, params)
OperationalError: server closed the connection unexpectedly
        This probably means the server terminated abnormally
        before or while processing the request.

Answer 1

这是与此处发布的问题非常类似的问题：

Django + FastCGI - randomly raising OperationalError

我想，如果有人最终弄明白，那么答案将是相同的。同样的问题一直困扰着我一个月左右，我不知道是什么原因造成的。

Answer 2

您是否fork()子进程（使用preforked FastCGI或类似的东西）？这可能是父进程中建立的连接在子进程中不起作用的原因。如果你使用preforked方法，很容易切换到线程，看看问题是否已经消失。在这种情况下，我看到完全相同的浮动错误。

Answer 3

即使这是一个非常古老的问题，我发现的最佳解决方案是this回答。只需执行以下操作：

{{1}}

在调用fork或使用多处理之前执行：

{{1}}

Answer 4

就我而言，我的WSGI服务器uWSGI正在派生我的应用程序进程，以便共享基础连接池。这导致了不确定的行为，（不确定地）正在像OP那样向下发送连接。

我建议确保热切地处理您的应用程序流程。在uWSGI中，您可以使用选项

lazy-apps = true

psycopg2与服务器断开连接

4 个答案: