mongos> db.system.views.find({"viewOn" : "ci_basic_custinfo_new_20180110_1"})
{ "_id" : "loan_his.ci_basic_custinfo_new", "viewOn" : "ci_basic_custinfo_new_20180110_1", "pipeline" : [ ] }
{ "_id" : "loan_his.ci_basic_custinfo", "viewOn" : "ci_basic_custinfo_new_20180110_1", "pipeline" : [ ] }
mongos> db.ci_basic_custinfo_new.aggregate([{$limit:1}])
{ "_id" : ObjectId("5a56dccc7bcaf49a450af5f0"), "objcod" : "14439", "objtype" : "3", "customer_id" : "XXX" }
mongos> db.ci_basic_custinfo.aggregate([{$limit:1}])
assert: command failed: {
        "ok" : 0,
        "errmsg" : "Namespace loan_his.ci_basic_custinfo is a view, not a collection",
        "code" : 166,
        "codeName" : "CommandNotSupportedOnView"
} : aggregate failed
_getErrorWithCode@src/mongo/shell/utils.js:25:13
doassert@src/mongo/shell/assert.js:16:14
assert.commandWorked@src/mongo/shell/assert.js:370:5
DBCollection.prototype.aggregate@src/mongo/shell/collection.js:1319:5
@(shell):1:1

2018-01-12T00:22:32.897+0800 E QUERY    [thread1] Error: command failed: {
        "ok" : 0,
        "errmsg" : "Namespace loan_his.ci_basic_custinfo is a view, not a collection",
        "code" : 166,
        "codeName" : "CommandNotSupportedOnView"
} : aggregate failed :
_getErrorWithCode@src/mongo/shell/utils.js:25:13
doassert@src/mongo/shell/assert.js:16:14
assert.commandWorked@src/mongo/shell/assert.js:370:5
DBCollection.prototype.aggregate@src/mongo/shell/collection.js:1319:5
@(shell):1:1
mongos> db.ci_basic_custinfo.aggregate([{$limit:1}])
assert: command failed: {
        "ok" : 0,
        "errmsg" : "Namespace loan_his.ci_basic_custinfo is a view, not a collection",
        "code" : 166,
        "codeName" : "CommandNotSupportedOnView"
} : aggregate failed
_getErrorWithCode@src/mongo/shell/utils.js:25:13
doassert@src/mongo/shell/assert.js:16:14
assert.commandWorked@src/mongo/shell/assert.js:370:5
DBCollection.prototype.aggregate@src/mongo/shell/collection.js:1319:5
@(shell):1:1

mongos> exit
bye


///////// restart the mongos service /////////////////////
[root@mongodb220 json]# service mongos restart
Restarting mongos (via systemctl):  
                                                           [  OK  ]
[root@mongodb220 json]# 
[root@mongodb220 json]# 
[root@mongodb220 json]# ml
MongoDB shell version v3.4.7
connecting to: mongodb://127.0.0.1:27017/loan_his
MongoDB server version: 3.4.7

2018-01-12T00:23:22.176+0800 I CONTROL  [main] 
mongos> db.ci_basic_custinfo.aggregate([{$limit:1}])
{ "_id" : ObjectId("5a56dccc7bcaf49a450af5f0"), "objcod" : "14439", "objtype" : "3", "customer_id" : "XXX" }
mongos> 


/////////////////// db.view.count() sometimes works sometimes doesn't //////
mongos> db.system.views.find({viewOn:"bifm02_20180115_1"})
{ "_id" : "loan_his.bifm02", "viewOn" : "bifm02_20180115_1", "pipeline" : [ ] }
mongos> db.bifm02.count()
3736
mongos> 


mongos> db.bifm02.count()
2018-01-11T23:01:12.001+0800 E QUERY    [thread1] Error: count failed: {
        "shards" : {

        },
        "cause" : {
                "ok" : 0,
                "errmsg" : "Namespace loan_his.bifm02 is a view, not a collection",
                "code" : 166,
                "codeName" : "CommandNotSupportedOnView"
        },
        "code" : 166,
        "ok" : 0,
        "errmsg" : "failed on : replset_sh220"
} :
_getErrorWithCode@src/mongo/shell/utils.js:25:13
DBQuery.prototype.count@src/mongo/shell/query.js:383:11
DBCollection.prototype.count@src/mongo/shell/collection.js:1700:12
@(shell):1:1