Start a sharded cluster with 2 shards mlaunch --sharded 2 --single launching: mongod on port 27018 launching: mongod on port 27019 launching: config server on port 27020 launching: mongos on port 27017 adding shards. Insert some data, shard the collection on _id (ve)tr@enter:~/Documents/tickets/CS-14146$ mongo MongoDB shell version: 2.6.3 connecting to: test mongos> db.getSisterDB( 'config' ).settings.update({}, {$set: {value: 1}}) WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 }) mongos> for ( var i = 0; i < 20000; i++) { ... db.coll.insert({field: i}) ... } WriteResult({ "nInserted" : 1 }) mongos> sh.enableSharding( 'test' ) { "ok" : 1 } mongos> sh.shardCollection( 'test.coll' , {_id: 1}) { "collectionsharded" : "test.coll" , "ok" : 1 } mongos> sh.status() --- Sharding Status --- sharding version: { "_id" : 1, "version" : 4, "minCompatibleVersion" : 4, "currentVersion" : 5, "clusterId" : ObjectId( "53e153e61a06f4155f0e2439" ) } shards: { "_id" : "shard0000" , "host" : "enter.local:27018" } { "_id" : "shard0001" , "host" : "enter.local:27019" } databases: { "_id" : "admin" , "partitioned" : false , "primary" : "config" } { "_id" : "test" , "partitioned" : true , "primary" : "shard0000" } test.coll shard key: { "_id" : 1 } chunks: shard0000 2 shard0001 1 { "_id" : { "$minKey" : 1 } } -->> { "_id" : ObjectId( "53e154266632858cc22a2205" ) } on : shard0000 Timestamp(2, 1) { "_id" : ObjectId( "53e154266632858cc22a2205" ) } -->> { "_id" : ObjectId( "53e154436632858cc22a530d" ) } on : shard0000 Timestamp(1, 3) { "_id" : ObjectId( "53e154436632858cc22a530d" ) } -->> { "_id" : { "$maxKey" : 1 } } on : shard0001 Timestamp(2, 0) Run a query that would return an empty document: mongos> db.coll.find({}, {nonexisting:1, _id:0}) mongos> db.coll.find({}, {nonexisting:1, _id:0}).itcount() 0 mongos> db.coll.find({}, {nonexisting:1, _id:0}).count() 20000 mongos> bye On mongod however: (ve)tr@enter:~/Documents/tickets/CS-14146$ mongo --port 27018 MongoDB shell version: 2.6.3 connecting to: 127.0.0.1:27018/test > db.coll.find({}, {nonexisting:1, _id:0}) { } { } { } { } { } { } { } { } { } { } { } { } { } { } { } { } { } { } { } { } Type "it" for more > db.coll.find({}, {nonexisting:1, _id:0}).count() 12552 > db.coll.find({}, {nonexisting:1, _id:0}).itcount() 12552 >