似乎使用pymongo，连接将始终尝试从PRIMARY 读取，当它关闭时，会引发套接字错误，直到新的选举过程完成。
鉴于replicSet的目的之一是平衡读取负载，这似乎是一个重大缺陷，除非我在这里错过了一个关键概念。
我提供了slave_ok thingy，但是，只要没有主要的可用，没有读取，更不用说写入了。
我已经在端口8910,8911和8912上启动了3个mongod实例，并且一个接一个地将它们关闭，当最后一个保留时，没有办法从中读取，即使你mongo（cli）让我们阅读。
正在使用的版本：
mongodb: 2.0.2
pymongo: 2.1.1
pymongo控制台输出
>>> collection = Connection("localhost:8910, localhost:8911, localhost:8912", slave_okay=True).testdb['TEST']
>>> len(list(collection.find()))
0
>>> collection.insert({"a": 1})
ObjectId('4f4a491bb9efb72ec8000045')
>>> len(list(collection.find()))
1
取下3个实例中的1个（主要实例），然后......
>>> len(list(collection.find()))
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/usr/local/lib/python2.7/dist-packages/pymongo-2.1.1-py2.7-linux-x86_64.egg/pymongo/cursor.py", line 703, in next
if len(self.__data) or self._refresh():
File "/usr/local/lib/python2.7/dist-packages/pymongo-2.1.1-py2.7-linux-x86_64.egg/pymongo/cursor.py", line 666, in _refresh
self.__uuid_subtype))
File "/usr/local/lib/python2.7/dist-packages/pymongo-2.1.1-py2.7-linux-x86_64.egg/pymongo/cursor.py", line 616, in __send_message
**kwargs)
File "/usr/local/lib/python2.7/dist-packages/pymongo-2.1.1-py2.7-linux-x86_64.egg/pymongo/connection.py", line 880, in _send_message_with_response
sock = self.__socket()
File "/usr/local/lib/python2.7/dist-packages/pymongo-2.1.1-py2.7-linux-x86_64.egg/pymongo/connection.py", line 686, in __socket
sock, from_pool = self.__pool.get_socket(host, port)
File "/usr/local/lib/python2.7/dist-packages/pymongo-2.1.1-py2.7-linux-x86_64.egg/pymongo/connection.py", line 165, in get_socket
self.sock = (pid, self.connect(host, port))
File "/usr/local/lib/python2.7/dist-packages/pymongo-2.1.1-py2.7-linux-x86_64.egg/pymongo/connection.py", line 127, in connect
s.connect((host, port))
File "/usr/lib/python2.7/socket.py", line 224, in meth
return getattr(self._sock,name)(*args)
socket.error: [Errno 111] Connection refused
>>>
选出了新的小学，然后......
>>> len(list(collection.find()))
1
取消3中的第二个实例，然后......
>>> collection.insert({"c": 3})
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/usr/local/lib/python2.7/dist-packages/pymongo-2.1.1-py2.7-linux-x86_64.egg/pymongo/collection.py", line 312, in insert
continue_on_error, self.__uuid_subtype), safe)
File "/usr/local/lib/python2.7/dist-packages/pymongo-2.1.1-py2.7-linux-x86_64.egg/pymongo/connection.py", line 811, in _send_message
sock = self.__socket()
File "/usr/local/lib/python2.7/dist-packages/pymongo-2.1.1-py2.7-linux-x86_64.egg/pymongo/connection.py", line 674, in __socket
host, port = self.__find_node()
File "/usr/local/lib/python2.7/dist-packages/pymongo-2.1.1-py2.7-linux-x86_64.egg/pymongo/connection.py", line 659, in __find_node
raise AutoReconnect(', '.join(errors))
pymongo.errors.AutoReconnect: could not connect to localhost:8911: [Errno -5] No address associated with hostname, could not connect to localhost:8911: [Errno 111] Connection refused, could not connect to localhost:8912: [Errno 111] Connection refused, could not connect to localhost:8912: [Errno -5] No address associated with hostname, localhost:8910 is not primary or master
>>>
>>>
>>> collection.insert({"c": 3})
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/usr/local/lib/python2.7/dist-packages/pymongo-2.1.1-py2.7-linux-x86_64.egg/pymongo/collection.py", line 312, in insert
continue_on_error, self.__uuid_subtype), safe)
File "/usr/local/lib/python2.7/dist-packages/pymongo-2.1.1-py2.7-linux-x86_64.egg/pymongo/connection.py", line 811, in _send_message
sock = self.__socket()
File "/usr/local/lib/python2.7/dist-packages/pymongo-2.1.1-py2.7-linux-x86_64.egg/pymongo/connection.py", line 674, in __socket
host, port = self.__find_node()
File "/usr/local/lib/python2.7/dist-packages/pymongo-2.1.1-py2.7-linux-x86_64.egg/pymongo/connection.py", line 659, in __find_node
raise AutoReconnect(', '.join(errors))
pymongo.errors.AutoReconnect: could not connect to localhost:8911: [Errno -5] No address associated with hostname, could not connect to localhost:8911: [Errno 111] Connection refused, could not connect to localhost:8912: [Errno 111] Connection refused, could not connect to localhost:8912: [Errno -5] No address associated with hostname, localhost:8910 is not primary or master
>>>
>>>
>>> len(list(collection.find()))
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/usr/local/lib/python2.7/dist-packages/pymongo-2.1.1-py2.7-linux-x86_64.egg/pymongo/cursor.py", line 703, in next
if len(self.__data) or self._refresh():
File "/usr/local/lib/python2.7/dist-packages/pymongo-2.1.1-py2.7-linux-x86_64.egg/pymongo/cursor.py", line 666, in _refresh
self.__uuid_subtype))
File "/usr/local/lib/python2.7/dist-packages/pymongo-2.1.1-py2.7-linux-x86_64.egg/pymongo/cursor.py", line 616, in __send_message
**kwargs)
File "/usr/local/lib/python2.7/dist-packages/pymongo-2.1.1-py2.7-linux-x86_64.egg/pymongo/connection.py", line 880, in _send_message_with_response
sock = self.__socket()
File "/usr/local/lib/python2.7/dist-packages/pymongo-2.1.1-py2.7-linux-x86_64.egg/pymongo/connection.py", line 674, in __socket
host, port = self.__find_node()
File "/usr/local/lib/python2.7/dist-packages/pymongo-2.1.1-py2.7-linux-x86_64.egg/pymongo/connection.py", line 659, in __find_node
raise AutoReconnect(', '.join(errors))
pymongo.errors.AutoReconnect: could not connect to localhost:8911: [Errno -5] No
address associated with hostname, could not connect to localhost:8911: [Errno 111]
Connection refused, could not connect to localhost:8912: [Errno 111] Connection refused,
could not connect to localhost:8912: [Errno -5] No address associated with hostname,
localhost:8910 is not primary or master
>>>
mongo（cli）输出
SECONDARY> rs.status()
{
"set" : "myset",
"date" : ISODate("2012-02-26T15:09:49Z"),
"myState" : 2,
"members" : [
{
"_id" : 0,
"name" : "localhost:8910",
"health" : 0,
"state" : 8,
"stateStr" : "(not reachable/healthy)",
"uptime" : 0,
"optime" : {
"t" : 1330268443000,
"i" : 1
},
"optimeDate" : ISODate("2012-02-26T15:00:43Z"),
"lastHeartbeat" : ISODate("2012-02-26T15:09:37Z"),
"pingMs" : 0,
"errmsg" : "socket exception"
},
{
"_id" : 1,
"name" : "localhost:8911",
"health" : 1,
"state" : 2,
"stateStr" : "SECONDARY",
"optime" : {
"t" : 1330268443000,
"i" : 1
},
"optimeDate" : ISODate("2012-02-26T15:00:43Z"),
"self" : true
},
{
"_id" : 2,
"name" : "localhost:8912",
"health" : 0,
"state" : 8,
"stateStr" : "(not reachable/healthy)",
"uptime" : 0,
"optime" : {
"t" : 1330268443000,
"i" : 1
},
"optimeDate" : ISODate("2012-02-26T15:00:43Z"),
"lastHeartbeat" : ISODate("2012-02-26T15:09:37Z"),
"pingMs" : 0,
"errmsg" : "socket exception"
}
],
"ok" : 1
}
SECONDARY>
SECONDARY>
SECONDARY> db.TEST.find().count()
54
SECONDARY> db.TEST.insert({eeee:23232323})
not master
SECONDARY>
SECONDARY> db.TEST.find().count()
54
答案 0 :(得分：4)
要解决此问题有两个因素，ReplicaSetConnection和ReadPreference.SECONDARY。
即
ReplicaSetConnection("localhost:8910,localhost:8911,localhost8912",
replicaSet='myset', read_prefererence=ReadPreference.SECONDARY)
答案 1 :(得分：1)
使用最新的PyMongo并实例化ReplicaSetConnection而不是Connection。使用ReadPreference将读取指向主要或次要;可以在ReplicaSetConnection中设置首选项，也可以在每个查询中重写：
http://api.mongodb.org/python/current/api/pymongo/index.html#pymongo.ReadPreference