MongoDB Shard offline mongos throw socket exception - mongodb

Question

I have question about use mongos with Shard，I build shard cluster in our dev environment
I had two shards(NOT include replset just for test) one config and one mongos
when I shutdown a shard the mongos can't find data(such as find(),count()...).it throw a socket exception
like this：
socket exception [CONNECT_ERROR] for 127.0.0.1:20000
code:11002
can anyone help me to figure out where is the problem,i saw the docs before it wrote about in the sharding cluster if a shard crashed the mongos can still work.
i appreciate your help,thx i use these shell to build it
shard 1
mongod --shardsvr --port 10000 --dbpath c:\shard\data\shard1\r0 --oplogSize 64 --logpath c:\shard\logs\r0.log --logappend
shard2
mongod --shardsvr --port 20000 --dbpath c:\shard\data\shard2\r0 --oplogSize 64 --logpath c:\shard\logs\r3.log --logappend
config
mongod --configsvr --dbpath c:\shard\data\config --port 40000 --logpath c:\shard\logs\config.log --logappend
mongos
mongos --configdb 127.0.0.1:40000 --port 50000 --chunkSize 1 --logpath c:\shard\logs\mongos.log --logappend
mongo 127.0.0.1:50000/admin
db.runCommand({addshard:"127.0.0.1:10000",name:"ShardSetA"})
db.runCommand({addshard:"127.0.0.1:20000",name:"ShardSetB"})
db.runCommand({enablesharding:"Staff"});
var server=["127.0.0.1:10000","127.0.0.1:20000"]
db.runCommand({shardcollection:"Staff.StaffInfo",key:{StaffName:1}})
for ( var x=65; x<=65+25; x+=10 ){
var index=x+10>65+25?65+25:x+10;
db.runCommand( { split : "Staff.StaffInfo" , middle : { StaffName: String.fromCharCode(index)} } );}
var i=0;
for ( var x=65; x<=97+25; x+=10 ){db.adminCommand( {moveChunk : "Staff.StaffInfo" ,find : {StaffName: x}, to : server[i%2] });i++}

Answer 1

I had solved this problem
there are three situations for the problem
1. query from normal shard ，mongodb can provide right data
2.query from all the shards(include offline shard) mongodb will throw exception
3.query from offline shard mongodb wiil throw exception
so if you want to keep high-performance sharding please use replset！
if you query from other dirvers please set partial flag to provide return data from normal shard