id	summary	reporter	owner	description	type	status	component	version	severity	resolution	keywords	cc	stage	has_patch	needs_docs	needs_tests	needs_better_patch	easy	ui_ux
17998	database threading issue with dev server and sqlite	anonymous	nobody	"Steps to reproduce:

 * Run dev server in the standard way ""./manage.py runserver""
 * Request a Django-served page in a browser
   * Likely important that the page has links to static media files
     served by the dev server so the browser initiates multiple simultaneous
     requests
   * There is middleware on the site that hits the session table in the db
     for every request, including the static media files
   * You may need to flush the browser cache when trying to repeatedly see the error

Expected behavior:

 * All files served normally

Observed behavior:

 * Non-deterministic, some requests cause an error
 * Error response is the following: ""A server error occurred.  Please contact the administrator.""
 * The exception in the error log reads:
{{{
DatabaseError: DatabaseWrapper objects created in a thread can only be used in that same thread. The object with alias 'default' was created in thread id 4374663168 and this is thread id 4385443840.
}}}
 * Note that the Django site in question is only using the Django ORM, not reaching deeper into the django.db library, and it does not explicitly spawn any threads
 * I'm including a full backtrace from the dev server below.

Environment:

 * Mac OS X 10.6.8
 * python27 @2.7.2_1 (MacPorts)
 * py27-sqlite @2.6.3_0 (MacPorts)
 * sqlite3 @3.7.11_0 (MacPorts)
 * Django 1.4.0-final0 (pip)
 * Firefox 11.0  

Full backtrace:

{{{
DEBUG:django.db.backends:(0.003) SELECT ""django_session"".""session_key"", ""django_session"".""session_data"", ""django_session"".""expire_date"" FROM ""django_session"" WHERE (""django_session"".""session_key"" = 02462878adc69e05312600990114b569  AND ""django_session"".""expire_date"" > 2012-03-28 10:29:14.458986 ); args=('02462878adc69e05312600990114b569', u'2012-03-28 10:29:14.458986')
DEBUG:django.db.backends:(0.000) SELECT (1) AS ""a"" FROM ""django_session"" WHERE ""django_session"".""session_key"" = 02462878adc69e05312600990114b569  LIMIT 1; args=('02462878adc69e05312600990114b569',)
DEBUG:django.db.backends:(0.000) UPDATE ""django_session"" SET ""session_data"" = NDY1YWVmMjI5ZTZiOGIxODUyMjVlMTAxOGQ2MjUzNTEzOWRmMWQ1NzqAAn1xAS4=
, ""expire_date"" = 2012-03-28 10:59:14.471961 WHERE ""django_session"".""session_key"" = 02462878adc69e05312600990114b569 ; args=('NDY1YWVmMjI5ZTZiOGIxODUyMjVlMTAxOGQ2MjUzNTEzOWRmMWQ1NzqAAn1xAS4=\n', u'2012-03-28 10:59:14.471961', '02462878adc69e05312600990114b569')
Traceback (most recent call last):
  File ""/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/wsgiref/handlers.py"", line 85, in run
    self.result = application(self.environ, self.start_response)
  File ""/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/contrib/staticfiles/handlers.py"", line 67, in __call__
    return self.application(environ, start_response)
  File ""/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/core/handlers/wsgi.py"", line 243, in __call__
    signals.request_finished.send(sender=self.__class__)
  File ""/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/dispatch/dispatcher.py"", line 172, in send
    response = receiver(signal=self, sender=sender, **named)
  File ""/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django_digest/backend/db.py"", line 54, in close_connection
    self.connection.close()
  File ""/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/db/backends/sqlite3/base.py"", line 319, in close
    self.validate_thread_sharing()
  File ""/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/db/backends/__init__.py"", line 136, in validate_thread_sharing
    % (self.alias, self._thread_ident, thread.get_ident()))
DatabaseError: DatabaseWrapper objects created in a thread can only be used in that same thread. The object with alias 'default' was created in thread id 4374663168 and this is thread id 4385443840.
[28/Mar/2012 10:29:14] ""GET / HTTP/1.1"" 500 59
}}}

Thanks very much, Django is great software!
"	Bug	closed	Database layer (models, ORM)	1.4	Normal	worksforme		anssi.kaariainen@…	Unreviewed	0	0	0	0	0	0