i use uwsgi,gevent to deploy production environment， the uwsgi only can use one process，one worker,(the server is flask,and the client is ios & android,i use this to develop app client，not browser)if too many processes and workeres，this will cause session invalid，but one process on work，sometimes will produce the error like this

[pid: 4876|app: 0|req: 14/11] 127.0.0.1 () {40 vars in 755 bytes} [Wed Mar 15 12:34:42 2017] GET /socket.io/?transport=polling&b64=1&token=81ff4591a14bd21a61afbd8fdce7f230&uid=32955967&gid=118&ssid=0 => generated 117 bytes in 4 msecs (HTTP/1.1 200) 4 headers in 181 bytes (3 switches on core 496)
Traceback (most recent call last):
File "/www/pyenv/lib/python2.7/site-packages/flask/app.py", line 1994, in call
return self.wsgi_app(environ, start_response)
File "/www/pyenv/lib/python2.7/site-packages/flask_socketio/init.py", line 42, in call
start_response)
File "/www/pyenv/lib/python2.7/site-packages/engineio/middleware.py", line 47, in call
return self.engineio_app.handle_request(environ, start_response)
File "/www/pyenv/lib/python2.7/site-packages/socketio/server.py", line 353, in handle_request
return self.eio.handle_request(environ, start_response)
File "/www/pyenv/lib/python2.7/site-packages/engineio/server.py", line 278, in handle_request
socket.handle_post_request(environ)
File "/www/pyenv/lib/python2.7/site-packages/engineio/socket.py", line 105, in handle_post_request
self.receive(pkt)
File "/www/pyenv/lib/python2.7/site-packages/engineio/socket.py", line 55, in receive
async=self.server.async_handlers)
File "/www/pyenv/lib/python2.7/site-packages/engineio/server.py", line 378, in _trigger_event
return self.handlersevent
File "/www/pyenv/lib/python2.7/site-packages/socketio/server.py", line 509, in _handle_eio_message
self._handle_connect(sid, pkt.namespace)
File "/www/pyenv/lib/python2.7/site-packages/socketio/server.py", line 415, in _handle_connect
self.manager.disconnect(sid, namespace)
File "/www/pyenv/lib/python2.7/site-packages/socketio/base_manager.py", line 68, in disconnect
for room_name, room in six.iteritems(self.rooms[namespace]):
KeyError: u'/xiyouws'

[pid: 4876|app: 0|req: 19/16] 127.0.0.1 () {44 vars in 891 bytes} [Wed Mar 15 12:34:42 2017] POST /socket.io/?transport=polling&b64=1&token=81ff4591a14bd21a61afbd8fdce7f230&uid=32955967&gid=118&ssid=0&sid=78c9d8c988b14c4faf0f1cd89c8283a6 => generated 2 bytes in 94 msecs (HTTP/1.1 200) 3 headers in 117 bytes (3 switches on core 496)
Traceback (most recent call last):
File "/www/pyenv/lib/python2.7/site-packages/flask/app.py", line 1994, in call
return self.wsgi_app(environ, start_response)
File "/www/pyenv/lib/python2.7/site-packages/flask_socketio/init.py", line 42, in call
start_response)
File "/www/pyenv/lib/python2.7/site-packages/engineio/middleware.py", line 47, in call
return self.engineio_app.handle_request(environ, start_response)
File "/www/pyenv/lib/python2.7/site-packages/socketio/server.py", line 353, in handle_request
return self.eio.handle_request(environ, start_response)
File "/www/pyenv/lib/python2.7/site-packages/engineio/server.py", line 298, in handle_request
start_response(r['status'], r['headers'] + cors_headers)
IOError: headers already sent
[pid: 4876|app: 0|req: 19/17] 127.0.0.1 () {38 vars in 747 bytes} [Wed Mar 15 12:34:42 2017] GET /socket.io/?transport=websocket&token=fb10ee56de95c2ecca512dd5158b4652&uid=32955967&gid=118&ssid=0&sid=0da764e5a4a54df2b8e2eb854136655f => generated 2 bytes in 639 msecs (HTTP/1.1 101) 4 headers in 181 bytes (1 switches on core 498)
Traceback (most recent call last):
File "/www/pyenv/lib/python2.7/site-packages/gevent/greenlet.py", line 536, in run
result = self._run(*self.args, **self.kwargs)
File "/www/pyenv/lib/python2.7/site-packages/engineio/async_gevent_uwsgi.py", line 53, in select_greenlet_runner
select([fd], [], [])[0]
File "/www/pyenv/lib/python2.7/site-packages/gevent/select.py", line 141, in select
sel_results = _original_select(rlist, wlist, xlist, 0)
error: (9, 'Bad file descriptor')
Wed Mar 15 12:34:42 2017 <Greenlet at 0x7f1138b26d70: select_greenlet_runner(12, <gevent.event.Event object at 0x7f11387d4e90>)> failed with error