my setup:

virtual machine with 2 cores and 4 gb ram debian 7 postgresql paster nginx mediagoblin 0.6.2.dev ​init script from joar

i want to test the performance of paster and evaluate other application-servers like gunicorn.

5 requests/sec works fine, but with 6 something breaks.

i get a "504 Gateway Time-out" from nginx, meaning the backend is not there.

also stopping of paster don't work:

root@mediagoblin:~# /etc/init.d/mediagoblin-paster stop
Stopping GNU MediaGoblin paster fcgi server: mediagoblin-paster failed!

if i kill the processes and restart it, it works again.

error from the paster log:

Error - <class 'sqlalchemy.exc.DatabaseError'>: (DatabaseError) error with no message from the libpq None None
URL: http://mediagoblin.lan/u/davidak/m/dsc-0046/
File '/var/www/mediagoblin/local/lib/python2.7/site-packages/Paste-1.7.5.1-py2.7.egg/paste/exceptions/errormiddleware.py', line 144 in __call__
  app_iter = self.application(environ, sr_checker)
File '/var/www/mediagoblin/local/lib/python2.7/site-packages/Paste-1.7.5.1-py2.7.egg/paste/urlmap.py', line 203 in __call__
  return app(environ, start_response)
File '/var/www/mediagoblin/mediagoblin/app.py', line 267 in __call__
  self.db.reset_after_request()
File '/var/www/mediagoblin/mediagoblin/db/open.py', line 48 in reset_after_request
  Session.rollback()
File '/var/www/mediagoblin/local/lib/python2.7/site-packages/SQLAlchemy-0.8.6-py2.7-linux-x86_64.egg/sqlalchemy/orm/scoping.py', line 149 in do
  return getattr(self.registry(), name)(*args, **kwargs)
File '/var/www/mediagoblin/local/lib/python2.7/site-packages/SQLAlchemy-0.8.6-py2.7-linux-x86_64.egg/sqlalchemy/orm/session.py', line 685 in rollback
  self.transaction.rollback()
File '/var/www/mediagoblin/local/lib/python2.7/site-packages/SQLAlchemy-0.8.6-py2.7-linux-x86_64.egg/sqlalchemy/orm/session.py', line 380 in rollback
  transaction._rollback_impl()
File '/var/www/mediagoblin/local/lib/python2.7/site-packages/SQLAlchemy-0.8.6-py2.7-linux-x86_64.egg/sqlalchemy/orm/session.py', line 408 in _rollback_impl
  t[1].rollback()
File '/var/www/mediagoblin/local/lib/python2.7/site-packages/SQLAlchemy-0.8.6-py2.7-linux-x86_64.egg/sqlalchemy/engine/base.py', line 1184 in rollback
  self._do_rollback()
File '/var/www/mediagoblin/local/lib/python2.7/site-packages/SQLAlchemy-0.8.6-py2.7-linux-x86_64.egg/sqlalchemy/engine/base.py', line 1222 in _do_rollback
  self.connection._rollback_impl()
File '/var/www/mediagoblin/local/lib/python2.7/site-packages/SQLAlchemy-0.8.6-py2.7-linux-x86_64.egg/sqlalchemy/engine/base.py', line 477 in _rollback_impl
  self._handle_dbapi_exception(e, None, None, None, None)
File '/var/www/mediagoblin/local/lib/python2.7/site-packages/SQLAlchemy-0.8.6-py2.7-linux-x86_64.egg/sqlalchemy/engine/base.py', line 1024 in _handle_dbapi_exception
  exc_info
File '/var/www/mediagoblin/local/lib/python2.7/site-packages/SQLAlchemy-0.8.6-py2.7-linux-x86_64.egg/sqlalchemy/util/compat.py', line 196 in raise_from_cause
  reraise(type(exception), exception, tb=exc_tb)
File '/var/www/mediagoblin/local/lib/python2.7/site-packages/SQLAlchemy-0.8.6-py2.7-linux-x86_64.egg/sqlalchemy/engine/base.py', line 474 in _rollback_impl
  self.engine.dialect.do_rollback(self.connection)
File '/var/www/mediagoblin/local/lib/python2.7/site-packages/SQLAlchemy-0.8.6-py2.7-linux-x86_64.egg/sqlalchemy/engine/default.py', line 294 in do_rollback
  dbapi_connection.rollback()
DatabaseError: (DatabaseError) error with no message from the libpq None None


CGI Variables
-------------
  DOCUMENT_ROOT: '/etc/nginx/html'
  DOCUMENT_URI: '/u/davidak/m/dsc-0046/'
  GATEWAY_INTERFACE: 'CGI/1.1'
  HTTP_ACCEPT: 'text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8'
  HTTP_ACCEPT_ENCODING: 'gzip,deflate,sdch'
  HTTP_ACCEPT_LANGUAGE: 'de-DE,de;q=0.8,en-US;q=0.6,en;q=0.4'
  HTTP_CACHE_CONTROL: 'max-age=0'
  HTTP_CONNECTION: 'keep-alive'
  HTTP_COOKIE: 'mediagoblin_csrftoken=1413966666120940524; mediagoblin_csrftoken=1413966666120940524; MGSession=eyJtZXNzYWdlcyI6W10sInVzZXJfaWQiOiIyIn0.Bj3ypQ.sqgR5cZlSfbRjiDb5df1RNU5020; mediagoblin_csrftoken=1413966666120940524'
  HTTP_DNT: '1'
  HTTP_HOST: 'mediagoblin.lan'
  HTTP_REFERER: 'http://mediagoblin.lan/'
  HTTP_USER_AGENT: 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_6_8) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/34.0.1847.116 Safari/537.36'
  PATH_INFO: '/u/davidak/m/dsc-0046/'
  REDIRECT_STATUS: '200'
  REMOTE_ADDR: '10.0.0.8'
  REMOTE_PORT: '55655'
  REQUEST_METHOD: 'GET'
  REQUEST_URI: '/u/davidak/m/dsc-0046/'
  SCRIPT_FILENAME: '/etc/nginx/html/u/davidak/m/dsc-0046/'
  SERVER_ADDR: '10.0.0.11'
  SERVER_NAME: 'mediagoblin.lan'
  SERVER_PORT: '80'
  SERVER_PROTOCOL: 'HTTP/1.1'
  SERVER_SOFTWARE: 'nginx/1.2.1'


WSGI Variables
--------------
  application: {(None, '/mgoblin_static'): <StaticURLParser '/var/www/mediagoblin/mediagoblin/static'>, (None, '/mgoblin_media'): <StaticURLParser '/var/www/mediagoblin/user_dev/media/public'>, (None, ''): <mediagoblin.app.MediaGoblinApp object at 0x1cb1750>, (None, '/plugin_static'): <StaticURLParser '/var/www/mediagoblin/user_dev/plugin_static'>, (None, '/theme_static'): <StaticURLParser '/var/www/mediagoblin/user_dev/theme_static'>}
  paste.throw_errors: True
  werkzeug.request: <Request 'http://mediagoblin.lan/u/davidak/m/dsc-0046/' [GET]>
  wsgi process: 'Multiprocess'
------------------------------------------------------------
Error - <class 'sqlalchemy.exc.DatabaseError'>: (DatabaseError) error with no message from the libpq 'SELECT core__users.id AS core__users_id, core__users.username AS core__users_username, core__users.email AS core__users_email, core__users.pw_hash AS core__users_pw_hash, core__users.created AS core__users_created, core__users.wants_comment_notification AS core__users_wants_comment_notification, core__users.wants_notifications AS core__users_wants_notifications, core__users.license_preference AS core__users_license_preference, core__users.url AS core__users_url, core__users.bio AS core__users_bio, core__users.uploaded AS core__users_uploaded, core__users.upload_limit AS core__users_upload_limit \nFROM core__users \nWHERE core__users.id = %(param_1)s' {'param_1': u'2'}
URL: http://mediagoblin.lan/u/davidak/m/dsc-0046/
File '/var/www/mediagoblin/local/lib/python2.7/site-packages/Paste-1.7.5.1-py2.7.egg/paste/exceptions/errormiddleware.py', line 144 in __call__
  app_iter = self.application(environ, sr_checker)
File '/var/www/mediagoblin/local/lib/python2.7/site-packages/Paste-1.7.5.1-py2.7.egg/paste/urlmap.py', line 203 in __call__
  return app(environ, start_response)
File '/var/www/mediagoblin/mediagoblin/app.py', line 263 in __call__
  return self.call_backend(environ, start_response)
File '/var/www/mediagoblin/mediagoblin/app.py', line 205 in call_backend
  mg_request.setup_user_in_request(request)
File '/var/www/mediagoblin/mediagoblin/tools/request.py', line 38 in setup_user_in_request
  request.user = User.query.get(request.session['user_id'])
File '/var/www/mediagoblin/local/lib/python2.7/site-packages/SQLAlchemy-0.8.6-py2.7-linux-x86_64.egg/sqlalchemy/orm/query.py', line 827 in get
  return loading.load_on_ident(self, key)
File '/var/www/mediagoblin/local/lib/python2.7/site-packages/SQLAlchemy-0.8.6-py2.7-linux-x86_64.egg/sqlalchemy/orm/loading.py', line 226 in load_on_ident
  return q.one()
File '/var/www/mediagoblin/local/lib/python2.7/site-packages/SQLAlchemy-0.8.6-py2.7-linux-x86_64.egg/sqlalchemy/orm/query.py', line 2323 in one
  ret = list(self)
File '/var/www/mediagoblin/local/lib/python2.7/site-packages/SQLAlchemy-0.8.6-py2.7-linux-x86_64.egg/sqlalchemy/orm/query.py', line 2366 in __iter__
  return self._execute_and_instances(context)
File '/var/www/mediagoblin/local/lib/python2.7/site-packages/SQLAlchemy-0.8.6-py2.7-linux-x86_64.egg/sqlalchemy/orm/query.py', line 2381 in _execute_and_instances
  result = conn.execute(querycontext.statement, self._params)
File '/var/www/mediagoblin/local/lib/python2.7/site-packages/SQLAlchemy-0.8.6-py2.7-linux-x86_64.egg/sqlalchemy/engine/base.py', line 662 in execute
  params)
File '/var/www/mediagoblin/local/lib/python2.7/site-packages/SQLAlchemy-0.8.6-py2.7-linux-x86_64.egg/sqlalchemy/engine/base.py', line 761 in _execute_clauseelement
  compiled_sql, distilled_params
File '/var/www/mediagoblin/local/lib/python2.7/site-packages/SQLAlchemy-0.8.6-py2.7-linux-x86_64.egg/sqlalchemy/engine/base.py', line 874 in _execute_context
  context)
File '/var/www/mediagoblin/local/lib/python2.7/site-packages/SQLAlchemy-0.8.6-py2.7-linux-x86_64.egg/sqlalchemy/engine/base.py', line 1024 in _handle_dbapi_exception
  exc_info
File '/var/www/mediagoblin/local/lib/python2.7/site-packages/SQLAlchemy-0.8.6-py2.7-linux-x86_64.egg/sqlalchemy/util/compat.py', line 196 in raise_from_cause
  reraise(type(exception), exception, tb=exc_tb)
File '/var/www/mediagoblin/local/lib/python2.7/site-packages/SQLAlchemy-0.8.6-py2.7-linux-x86_64.egg/sqlalchemy/engine/base.py', line 867 in _execute_context
  context)
File '/var/www/mediagoblin/local/lib/python2.7/site-packages/SQLAlchemy-0.8.6-py2.7-linux-x86_64.egg/sqlalchemy/engine/default.py', line 324 in do_execute
  cursor.execute(statement, parameters)
DatabaseError: (DatabaseError) error with no message from the libpq 'SELECT core__users.id AS core__users_id, core__users.username AS core__users_username, core__users.email AS core__users_email, core__users.pw_hash AS core__users_pw_hash, core__users.created AS core__users_created, core__users.wants_comment_notification AS core__users_wants_comment_notification, core__users.wants_notifications AS core__users_wants_notifications, core__users.license_preference AS core__users_license_preference, core__users.url AS core__users_url, core__users.bio AS core__users_bio, core__users.uploaded AS core__users_uploaded, core__users.upload_limit AS core__users_upload_limit \nFROM core__users \nWHERE core__users.id = %(param_1)s' {'param_1': u'2'}


CGI Variables
-------------
  DOCUMENT_ROOT: '/etc/nginx/html'
  DOCUMENT_URI: '/u/davidak/m/dsc-0046/'
  GATEWAY_INTERFACE: 'CGI/1.1'
  HTTP_ACCEPT: 'text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8'
  HTTP_ACCEPT_ENCODING: 'gzip,deflate,sdch'
  HTTP_ACCEPT_LANGUAGE: 'de-DE,de;q=0.8,en-US;q=0.6,en;q=0.4'
  HTTP_CACHE_CONTROL: 'max-age=0'
  HTTP_CONNECTION: 'keep-alive'
  HTTP_COOKIE: 'mediagoblin_csrftoken=1413966666120940524; mediagoblin_csrftoken=1413966666120940524; MGSession=eyJtZXNzYWdlcyI6W10sInVzZXJfaWQiOiIyIn0.Bj3ypQ.sqgR5cZlSfbRjiDb5df1RNU5020; mediagoblin_csrftoken=1413966666120940524'
  HTTP_DNT: '1'
  HTTP_HOST: 'mediagoblin.lan'
  HTTP_USER_AGENT: 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_6_8) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/34.0.1847.116 Safari/537.36'
  PATH_INFO: '/u/davidak/m/dsc-0046/'
  REDIRECT_STATUS: '200'
  REMOTE_ADDR: '10.0.0.8'
  REMOTE_PORT: '55705'
  REQUEST_METHOD: 'GET'
  REQUEST_URI: '/u/davidak/m/dsc-0046/'
  SCRIPT_FILENAME: '/etc/nginx/html/u/davidak/m/dsc-0046/'
  SERVER_ADDR: '10.0.0.11'
  SERVER_NAME: 'mediagoblin.lan'
  SERVER_PORT: '80'
  SERVER_PROTOCOL: 'HTTP/1.1'
  SERVER_SOFTWARE: 'nginx/1.2.1'


WSGI Variables
--------------
  application: {(None, '/mgoblin_static'): <StaticURLParser '/var/www/mediagoblin/mediagoblin/static'>, (None, '/mgoblin_media'): <StaticURLParser '/var/www/mediagoblin/user_dev/media/public'>, (None, ''): <mediagoblin.app.MediaGoblinApp object at 0x1cb1750>, (None, '/plugin_static'): <StaticURLParser '/var/www/mediagoblin/user_dev/plugin_static'>, (None, '/theme_static'): <StaticURLParser '/var/www/mediagoblin/user_dev/theme_static'>}
  paste.throw_errors: True
  werkzeug.request: <Request 'http://mediagoblin.lan/u/davidak/m/dsc-0046/' [GET]>
  wsgi process: 'Multiprocess'
------------------------------------------------------------

2014-04-27 06:29:41,495 WARNING [mediagoblin.tools.request] Killing session for user id u'2'
Error - <class 'sqlalchemy.exc.NoSuchColumnError'>: "Could not locate column in row for column 'core__user_bans.user_id'"
URL: http://mediagoblin.lan/u/davidak/m/dsc-0046/
File '/var/www/mediagoblin/local/lib/python2.7/site-packages/Paste-1.7.5.1-py2.7.egg/paste/exceptions/errormiddleware.py', line 144 in __call__
  app_iter = self.application(environ, sr_checker)
File '/var/www/mediagoblin/local/lib/python2.7/site-packages/Paste-1.7.5.1-py2.7.egg/paste/urlmap.py', line 203 in __call__
  return app(environ, start_response)
File '/var/www/mediagoblin/mediagoblin/app.py', line 263 in __call__
  return self.call_backend(environ, start_response)
File '/var/www/mediagoblin/mediagoblin/app.py', line 240 in call_backend
  response = controller(request)
File '/var/www/mediagoblin/mediagoblin/decorators.py', line 43 in wrapper
  if request.user.is_banned():
File '/var/www/mediagoblin/mediagoblin/db/models.py', line 136 in is_banned
  return UserBan.query.get(self.id) is not None
File '/var/www/mediagoblin/local/lib/python2.7/site-packages/SQLAlchemy-0.8.6-py2.7-linux-x86_64.egg/sqlalchemy/orm/query.py', line 827 in get
  return loading.load_on_ident(self, key)
File '/var/www/mediagoblin/local/lib/python2.7/site-packages/SQLAlchemy-0.8.6-py2.7-linux-x86_64.egg/sqlalchemy/orm/loading.py', line 226 in load_on_ident
  return q.one()
File '/var/www/mediagoblin/local/lib/python2.7/site-packages/SQLAlchemy-0.8.6-py2.7-linux-x86_64.egg/sqlalchemy/orm/query.py', line 2323 in one
  ret = list(self)
File '/var/www/mediagoblin/local/lib/python2.7/site-packages/SQLAlchemy-0.8.6-py2.7-linux-x86_64.egg/sqlalchemy/orm/loading.py', line 72 in instances
  rows = [process[0](row, None) for row in fetch]
File '/var/www/mediagoblin/local/lib/python2.7/site-packages/SQLAlchemy-0.8.6-py2.7-linux-x86_64.egg/sqlalchemy/orm/loading.py', line 356 in _instance
  tuple([row[column] for column in pk_cols])
File '/var/www/mediagoblin/local/lib/python2.7/site-packages/SQLAlchemy-0.8.6-py2.7-linux-x86_64.egg/sqlalchemy/engine/result.py', line 314 in _key_fallback
  expression._string_or_unprintable(key))
NoSuchColumnError: "Could not locate column in row for column 'core__user_bans.user_id'"


CGI Variables
-------------
  CSRF_TOKEN: u'1413966666120940524'
  DOCUMENT_ROOT: '/etc/nginx/html'
  DOCUMENT_URI: '/u/davidak/m/dsc-0046/'
  GATEWAY_INTERFACE: 'CGI/1.1'
  HTTP_ACCEPT: 'text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8'
  HTTP_ACCEPT_ENCODING: 'gzip,deflate,sdch'
  HTTP_ACCEPT_LANGUAGE: 'de-DE,de;q=0.8,en-US;q=0.6,en;q=0.4'
  HTTP_CACHE_CONTROL: 'max-age=0'
  HTTP_CONNECTION: 'keep-alive'
  HTTP_COOKIE: 'mediagoblin_csrftoken=1413966666120940524; mediagoblin_csrftoken=1413966666120940524; MGSession=eyJtZXNzYWdlcyI6W10sInVzZXJfaWQiOiIyIn0.Bj3ypQ.sqgR5cZlSfbRjiDb5df1RNU5020; arp_scroll_position=191; mediagoblin_csrftoken=1413966666120940524'
  HTTP_DNT: '1'
  HTTP_HOST: 'mediagoblin.lan'
  HTTP_REFERER: 'http://mediagoblin.lan/'
  HTTP_USER_AGENT: 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_6_8) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/34.0.1847.116 Safari/537.36'
  PATH_INFO: '/u/davidak/m/dsc-0046/'
  REDIRECT_STATUS: '200'
  REMOTE_ADDR: '10.0.0.8'
  REMOTE_PORT: '56201'
  REQUEST_METHOD: 'GET'
  REQUEST_URI: '/u/davidak/m/dsc-0046/'
  SCRIPT_FILENAME: '/etc/nginx/html/u/davidak/m/dsc-0046/'
  SERVER_ADDR: '10.0.0.11'
  SERVER_NAME: 'mediagoblin.lan'
  SERVER_PORT: '80'
  SERVER_PROTOCOL: 'HTTP/1.1'
  SERVER_SOFTWARE: 'nginx/1.2.1'


WSGI Variables
--------------
  application: {(None, '/mgoblin_static'): <StaticURLParser '/var/www/mediagoblin/mediagoblin/static'>, (None, '/mgoblin_media'): <StaticURLParser '/var/www/mediagoblin/user_dev/media/public'>, (None, ''): <mediagoblin.app.MediaGoblinApp object at 0x2efe750>, (None, '/plugin_static'): <StaticURLParser '/var/www/mediagoblin/user_dev/plugin_static'>, (None, '/theme_static'): <StaticURLParser '/var/www/mediagoblin/user_dev/theme_static'>}
  paste.throw_errors: True
  werkzeug.request: <Request 'http://mediagoblin.lan/u/davidak/m/dsc-0046/' [GET]>
  wsgi process: 'Multiprocess'
------------------------------------------------------------

my setup:

virtual machine with 2 cores and 4 gb ram debian 7 postgresql paster nginx mediagoblin 0.6.2.dev ​init script from joar

i uploaded some videos. they get transcoded, but after some time it stops. new uploaded media don't appear on the website.

also stopping of celery don't work.

root@mediagoblin:~# /etc/init.d/mediagoblin-celeryd stop
Stopping GNU MediaGoblin Celery task queue: mediagoblin-celerydFailed to shut down after 20 seconds. Aborting.
 failed!

very often the same lines in the celery log:

Traceback (most recent call last):
  File "/var/www/mediagoblin/mediagoblin/media_types/video/transcoders.py", line 687, in _on_message
    self._progress_callback(data.get('percent'))
  File "/var/www/mediagoblin/mediagoblin/processing/__init__.py", line 43, in __call__
    self.entry.save()
  File "/var/www/mediagoblin/mediagoblin/db/base.py", line 39, in save
    sess.commit()
  File "/var/www/mediagoblin/local/lib/python2.7/site-packages/SQLAlchemy-0.8.6-py2.7-linux-x86_64.egg/sqlalchemy/orm/session.py", line 721, in commit
    self.transaction.commit()
  File "/var/www/mediagoblin/local/lib/python2.7/site-packages/SQLAlchemy-0.8.6-py2.7-linux-x86_64.egg/sqlalchemy/orm/session.py", line 352, in commit
    self._assert_active(prepared_ok=True)
  File "/var/www/mediagoblin/local/lib/python2.7/site-packages/SQLAlchemy-0.8.6-py2.7-linux-x86_64.egg/sqlalchemy/orm/session.py", line 194, in _assert_active
    % self._rollback_exception
sqlalchemy.exc.InvalidRequestError: This Session's transaction has been rolled back due to a previous exception during flush. To begin a new transaction with this Session, first issue Session.rollback(). Original exception was: This result object does not return rows. It has been closed automatically.
/var/www/mediagoblin/local/lib/python2.7/site-packages/celery-3.1.10-py2.7.egg/celery/app/trace.py:348: RuntimeWarning: Exception raised outside body: InvalidRequestError("This Session's transaction has been rolled back due to a previous exception during flush. To begin a new transaction with this Session, first issue Session.rollback(). Original exception was: This result object does not return rows. It has been closed automatically.",):
Traceback (most recent call last):
  File "/var/www/mediagoblin/local/lib/python2.7/site-packages/celery-3.1.10-py2.7.egg/celery/app/trace.py", line 253, in trace_task
    I, R, state, retval = on_error(task_request, exc, uuid)
  File "/var/www/mediagoblin/local/lib/python2.7/site-packages/celery-3.1.10-py2.7.egg/celery/app/trace.py", line 201, in on_error
    R = I.handle_error_state(task, eager=eager)
  File "/var/www/mediagoblin/local/lib/python2.7/site-packages/celery-3.1.10-py2.7.egg/celery/app/trace.py", line 85, in handle_error_state
    }[self.state](task, store_errors=store_errors)
  File "/var/www/mediagoblin/local/lib/python2.7/site-packages/celery-3.1.10-py2.7.egg/celery/app/trace.py", line 120, in handle_failure
    task.on_failure(exc, req.id, req.args, req.kwargs, einfo)
  File "/var/www/mediagoblin/mediagoblin/processing/task.py", line 154, in on_failure
    mark_entry_failed(entry_id, exc)
  File "/var/www/mediagoblin/mediagoblin/processing/__init__.py", line 334, in mark_entry_failed
    u'fail_metadata': {}})
  File "/var/www/mediagoblin/mediagoblin/db/util.py", line 31, in atomic_update
    synchronize_session=False)
  File "/var/www/mediagoblin/local/lib/python2.7/site-packages/SQLAlchemy-0.8.6-py2.7-linux-x86_64.egg/sqlalchemy/orm/query.py", line 2710, in update
    update_op.exec_()
  File "/var/www/mediagoblin/local/lib/python2.7/site-packages/SQLAlchemy-0.8.6-py2.7-linux-x86_64.egg/sqlalchemy/orm/persistence.py", line 829, in exec_
    self._do_pre()
  File "/var/www/mediagoblin/local/lib/python2.7/site-packages/SQLAlchemy-0.8.6-py2.7-linux-x86_64.egg/sqlalchemy/orm/persistence.py", line 851, in _do_pre
    session._autoflush()
  File "/var/www/mediagoblin/local/lib/python2.7/site-packages/SQLAlchemy-0.8.6-py2.7-linux-x86_64.egg/sqlalchemy/orm/session.py", line 1139, in _autoflush
    self.flush()
  File "/var/www/mediagoblin/local/lib/python2.7/site-packages/SQLAlchemy-0.8.6-py2.7-linux-x86_64.egg/sqlalchemy/orm/session.py", line 1824, in flush
    self._flush(objects)
  File "/var/www/mediagoblin/local/lib/python2.7/site-packages/SQLAlchemy-0.8.6-py2.7-linux-x86_64.egg/sqlalchemy/orm/session.py", line 1902, in _flush
    subtransactions=True)
  File "/var/www/mediagoblin/local/lib/python2.7/site-packages/SQLAlchemy-0.8.6-py2.7-linux-x86_64.egg/sqlalchemy/orm/session.py", line 645, in begin
    nested=nested)
  File "/var/www/mediagoblin/local/lib/python2.7/site-packages/SQLAlchemy-0.8.6-py2.7-linux-x86_64.egg/sqlalchemy/orm/session.py", line 215, in _begin
    self._assert_active()
  File "/var/www/mediagoblin/local/lib/python2.7/site-packages/SQLAlchemy-0.8.6-py2.7-linux-x86_64.egg/sqlalchemy/orm/session.py", line 194, in _assert_active
    % self._rollback_exception
InvalidRequestError: This Session's transaction has been rolled back due to a previous exception during flush. To begin a new transaction with this Session, first issue Session.rollback(). Original exception was: This result object does not return rows. It has been closed automatically.

i uploaded 3 videos and 3 pictures, after some seconds celery stops working. the processes are still there but can't get stopped with the init script from joar. (some processes are still there, also the pidfile)

root@mediagoblin2:/var/www/mediagoblin# /etc/init.d/mediagoblin-celeryd status
mediagoblin-celeryd start/running, process 2851
root@mediagoblin2:/var/www/mediagoblin# /etc/init.d/mediagoblin-celeryd stop
Stopping GNU MediaGoblin Celery task queue: mediagoblin-celerydFailed to shut down after 20 seconds. Aborting.
 failed!

also strange is, that 2 files get the id of celery task as name (see picture).

my setup: vm with 8 cores and 2048 mb ram debian 7 postgres gunicorn nginx newest mediagoblin