11. {
"_id" : <unspecified>, //file ID
"length" : data_number, // bytes
"chunkSize" : data_number, // :256KB
"uploadDate" : data_date, //file
"md5" : data_string //"filemd5"
}

12. {
"filename" : data_string,
"contentType" : data_string,
"aliases" : data_array of data_string,
"metadata" : data_object,
}

13. {
"_id" : <unspecified>, //chunk ID
"files_id" : <unspecified>, //file _id
"n" : chunk_number, //0 chunk
0,1,2... chunk
"data" : data_binary, // BSON
}

14. > db.fs.chunks.ensureIndex(
{files_id:1, n:1}, {unique: true});
> db.fs.chunks.findOne({files_id: myFileID, n: 0});

15. ➜ ~ mongofiles --help
usage: mongofiles [options] command [gridfs filename]
command:
one of (list|search|put|get)
list - file
search - file
put - file
get - file
delete - file

16. ➜ ~ mongofiles list
connected to: 127.0.0.1
➜ ~ mongofiles put ByeForNow.mp3
connected to: 127.0.0.1
added file: { _id: ObjectId('4df17f8d9d47ba5c0247e72e'),
filename: "ByeForNow.mp3", chunkSize: 262144, uploadDate:
new Date(1307672462538), md5:
"9ee9472200a2e18bf376ce622c3b0055", length: 11183104 }
done!
➜ ~ mongofiles list -v // -v
Fri Jun 10 11:21:05 creating new connection to:127.0.0.1
Fri Jun 10 11:21:05 BackgroundJob starting:
connected to: 127.0.0.1
ByeForNow.mp3 11183104

17. ➜ ~ mongofiles put Maria.mp3
connected to: 127.0.0.1
added file: { _id: ObjectId('4df181fc5e354129e833193f'),
filename: "Maria.mp3", chunkSize: 262144, uploadDate: new
Date(1307673086293), md5:
"9d4f424fa1843711e196e502d8a00183", length: 12225353 }
done!
➜ ~ mongofiles list
connected to: 127.0.0.1
ByeForNow.mp3 11183104
Maria.mp3 12225353
➜ ~ mongofiles list M
connected to: 127.0.0.1
Maria.mp3 12225353
➜ ~ mongofiles search .mp3
connected to: 127.0.0.1
ByeForNow.mp3 11183104
Maria.mp3 12225353

18. ➜ ~ mkdir tmp // get
➜ ~ cd tmp
➜ mongofiles get Maria.mp3
connected to: 127.0.0.1
done write to: Maria.mp3
➜ ls
Maria.mp3
➜ mongofiles get Bye
ERROR: file not found
➜ mongofiles get ByeForNow.mp3
done write to: ByeForNow.mp3
➜ md5 Maria.mp3
MD5 (Maria.mp3) = 9d4f424fa1843711e196e502d8a00183
➜ md5 ../Maria.mp3
MD5 (../Maria.mp3) = 9d4f424fa1843711e196e502d8a00183

19. > db.fs.files.find().forEach(printjson)
{
"_id" : ObjectId("4df17f8d9d47ba5c0247e72e"),
"filename" : "ByeForNow.mp3",
"chunkSize" : 262144,
"uploadDate" : ISODate("2011-06-10T02:21:02.538Z"),
"md5" : "9ee9472200a2e18bf376ce622c3b0055",
"length" : 11183104
}
{
"_id" : ObjectId("4df181fc5e354129e833193f"),
"filename" : "Maria.mp3",
"chunkSize" : 262144,
"uploadDate" : ISODate("2011-06-10T02:31:26.293Z"),
"md5" : "9d4f424fa1843711e196e502d8a00183",
"length" : 12225353
}

20. > db.fs.chunks.findOne(
{n:0,files_id:ObjectId("4df181fc5e354129e833193f")})
{
"_id" : ObjectId("4df181fcd40994ca1de28d09"),
"files_id" : ObjectId("4df181fc5e354129e833193f"),
"n" : 0,
"data" : BinData(0,"SUQzAwAAAABQdlRSQ0sAAAACAAAAM1RJVDIA
AAAHAAAAg32DioNBVUZJRAAAAGYAAGh0dHA6Ly93d3cuY2RkYi5jb20vaWQ
zL3RhZ2luZm8xLmh0bWwAM0NEM00xMTBRMjA3NTYwOTc4VjY4MTBCQTlBNj
UzN0JCQUQ1QTgyOUE4NTRCRkQ2QTdBRjNQOAAAAAAAAAAAAEdFT0IAACNgA
AAAYXBwbGljYX...)
}

21. > db.fs.chunks.ensureIndex({files_id: 1});
> db.runCommand({ shardcollection : "test.fs.chunks", key :
{ files_id : 1 }})
{ "collectionsharded" : "test.fs.chunks", "ok" : 1 }

22. MongoDB GridFS

23. Replace Amazon S3 with MongoDB GridFS and Grails

26. { loc : [ 50 , 30 ] }
{ loc : { x : 50 , y : 30 } }
{ loc : { foo : 50 , y : 30 } }
{ loc : { long : 40.739037, lat: 73.992964 } }

27. db.places.ensureIndex( { loc : "2d" } )
db.places.ensureIndex( { loc : "2d" } , { min : -500 , max : 500 } )

28. db.places.find( { loc : [50,50] } )
db.places.find( { loc : { $near : [50,50] } } )
db.places.find( { loc : { $near : [50,50] } } ).limit(20)
db.places.find( { loc : { $near : [50,50] ,
$maxDistance : 5 } } ).limit(20)

29. //
> box = [[40.73083, -73.99756], [40.741404, -73.988135]]
> db.places.find({"loc" : {"$within" : {"$box" : box}}})
//
> center = [50, 50]
> radius = 10
> db.places.find({"loc" : {"$within" : {"$center" : [center, radius]}}})
// v1.9
> polygonA = [ [ 10, 20 ], [ 10, 40 ], [ 30, 40 ], [ 30, 20 ] ]
> polygonB = { a : { x : 10, y : 20 }, b : { x : 15, y : 25 }, c : { x :
20, y : 20 } }
> db.places.find({ "loc" : { "$within" : { "$polygon" : polygonA } } })
> db.places.find({ "loc" : { "$within" : { "$polygon" : polygonB } } })

30. > db.runCommand( { geoNear : "places" , near : [ 50 , 50 ], num : 10,
query : { type : "museum" } } );
{
"ns" : "test.places",
"near" : "1100110000001111110000001111110000001111110000001111",
"results" : [
{
"dis" : 69.29646421910687,
"obj" : {
"_id" : ObjectId("4b8bd6b93b83c574d8760280"),
"y" : [
1,
1
],
"category" : "Coffee"
}
},
{
"dis" : 69.29646421910687,
"obj" : {
"_id" : ObjectId("4b8bd6b03b83c574d876027f"),
1
...}

31. MongoDB

33. > db.points.insert({ pos : { long : 30, lat : 30 } })
> db.points.insert({ pos : { long : -10, lat : -20 } })
> db.points.ensureIndex({ pos : "2d" })
> db.points.find({ pos: { $nearSphere: [0,0], $maxDistance : 0.4 } })
{ "_id" : ObjectId("4df11e47b8e84370f84afdd3"), "pos" : { "long" : -10,
"lat" : -20 } }

34. > var earthRadius = 6378 // km
> var range = 3000 // km
> distances = db.runCommand({ geoNear : "points", near : [0, 0], spherical :
true, maxDistance : range / earthRadius }).results
[
{
"dis" : 0.3886630122897946, //
"obj" : {
"_id" : ObjectId("4df11e47b8e84370f84afdd3"),
"pos" : {
"long" : -10,
"lat" : -20
}
}
}
]
> pointDistance = distances[0].dis * earthRadius
2478.89269238431 // km

43. http://www.slideshare.net/doryokujin/mongo-sharding

46. ~ mkdir -p shard/shard00
~ mkdir -p shard/shard01
~ mkdir -p shard/shard02
~ mkdir -p shard/config
~ mongod --shardsvr --port 27017 --dbpath shard/shard00
~ mongod --shardsvr --port 27018 --dbpath shard/shard01
~ mongod --shardsvr --port 27019 --dbpath shard/shard02
~ mongod --configsvr --port 27020 --dbpath shard/config
~ mongos --configdb localhost:27020 --port 27021

47. ➜ ~ mongo localhost:27021 // mongos
MongoDB shell version: 1.8.0
connecting to: localhost:27021/test
> show dbs
config 0.1875GB // sharding
> db.adminCommand( { addshard: "localhost:27017", name: "shard00" } )
{ "shardAdded" : "shard00", "ok" : 1 }
> db.adminCommand( { addshard: "localhost:27018", name: "shard01" } )
{ "shardAdded" : "shard01", "ok" : 1 }
> db.adminCommand( { addshard: "localhost:27019", name: "shard02" } )
{ "shardAdded" : "shard02", "ok" : 1 }

48. // mongos
> db.adminCommand( { enablesharding : "test" } )
{ "ok" : 1 }
> db.adminCommand( { moveprimary : "test", to : "shard02" } );
{ "primary " : "shard02:localhost:27019", "ok" : 1 }
> db.adminCommand( { shardcollection : "test.myshard", key : { n : 1 } } )
{ "collectionsharded" : "test.myshard", "ok" : 1 }

49. // mongos
> db.adminCommand({split : "test.myshard", middle : { n: 0 } } )
{ "ok" : 1 }
> db.adminCommand({split : "test.myshard", middle : { n: 1 } } )
{ "ok" : 1 }
> db.adminCommand({split : "test.myshard", middle : { n: 2 } } )
{ "ok" : 1 }

50. > db.printShardingStatus() //
--- Sharding Status ---
sharding version: { "_id" : 1, "version" : 3 }
shards:
{ "_id" : "shard00", "host" : "localhost:27017" }
{ "_id" : "shard01", "host" : "localhost:27018" }
{ "_id" : "shard02", "host" : "localhost:27019" }
databases:
{ "_id" : "admin", "partitioned" : false, "primary" : "config" }
{ "_id" : "test", "partitioned" : true, "primary" : "shard02" }
test.myshard chunks:
shard02 4
{ "n" : { $minKey : 1 } } -->> { "n" : 0 } on : shard02 { "t" : 1000, "i" : 1 }
{ "n" : 0 } -->> { "n" : 1 } on : shard02 { "t" : 1000, "i" : 3 }
{ "n" : 1 } -->> { "n" : 2 } on : shard02 { "t" : 1000, "i" : 5 }
{ "n" : 2 } -->> { "n" : { $maxKey : 1 } } on : shard02 { "t" : 1000, "i" : 6 }

51. // mongos
> db.adminCommand({moveChunk: "test.myshard", find: { n: 0 }, to: "shard00" });
{ "millis" : 1051, "ok" : 1 }
> db.adminCommand({moveChunk: "test.myshard", find: { n: 1 }, to: "shard01" });
{ "millis" : 1046, "ok" : 1 }
> db.adminCommand({moveChunk :"test.myshard", find: { n: 2 }, to: "shard02" });
{ "ok" : 0, "errmsg" : "that chunk is already on that shard" }

52. > db.printShardingStatus()
--- Sharding Status ---
sharding version: { "_id" : 1, "version" : 3 }
shards:
{ "_id" : "shard00", "host" : "localhost:27017" }
{ "_id" : "shard01", "host" : "localhost:27018" }
{ "_id" : "shard02", "host" : "localhost:27019" }
databases:
{ "_id" : "admin", "partitioned" : false, "primary" : "config" }
{ "_id" : "test", "partitioned" : true, "primary" : "shard02" }
test.myshard chunks:
shard02 2
shard00 1
shard01 1
{ "n" : { $minKey : 1 } } -->> { "n" : 0 } on : shard02 { "t" : 3000, "i" : 1 }
{ "n" : 0 } -->> { "n" : 1 } on : shard00 { "t" : 2000, "i" : 0 }
{ "n" : 1 } -->> { "n" : 2 } on : shard01 { "t" : 3000, "i" : 0 }
{ "n" : 2 } -->> { "n" : { $maxKey : 1 } } on : shard02 { "t" : 1000, "i" : 6 }

53. // mongos
> for(var m=0; m<100; m++){ db.myshard.insert({n: m % 3}) } // n =0,1,2,0,1,...
> printShardingSizes() // Shard
...
test.myshard chunks:
{ "n" : { $minKey : 1 } } -->> { "n" : 0 } on : shard02 { "estimate" :
false, "size" : 0, "numObjects" : 0 }
{ "n" : 0 } -->> { "n" : 1 } on : shard00 { "estimate" : false, "size" :
1224, "numObjects" : 34 }
{ "n" : 1 } -->> { "n" : 2 } on : shard01 { "estimate" : false, "size" :
1188, "numObjects" : 33 }
{ "n" : 2 } -->> { "n" : { $maxKey : 1 } } on : shard02 { "estimate" :
false, "size" : 1188, "numObjects" : 33 }

54. ➜ ~ mongo localhost:27017
> db.myshard.count()
34
> db.myshard.distinct("n")
[ 0 ]
➜ ~ mongo localhost:27018
> db.myshard.count()
33
> db.myshard.distinct("n")
[ 1 ]
➜ ~ mongo localhost:27019
> db.myshard.count()
33
> db.myshard.distinct("n")
[ 2 ]

57. > db.adminCommand( { addshard: "set00/delta1:27017,delta2:27017", name:
"shard00" } )
{ "shardAdded" : "shard00", "ok" : 1 }
> db.adminCommand( { addshard: "set01/delta3:27018,delta4:27018", name:
"shard01" } )
{ "shardAdded" : "shard01", "ok" : 1 }
> db.adminCommand( { addshard: "set02/delta5:27019,delta6:27019", name:
"shard02" } )
{ "shardAdded" : "shard02", "ok" : 1 }

64. Map-Reduce on Mongo

67. db.mycoll.mapReduce(
map : <map >,
reduce : <reduce >
[, finalize : <finalize >]
[, query : < >]
[, sort : <
reduce >]
[, out : < >]
[, scope : <object where fields go into javascript global scope >]
);

68. db.people.insert({userId:1, age:24, type:"A"})
db.people.insert({userId:2, age:47, type:"B"})
db.people.insert({userId:3, age:34, type:"C"})
db.people.insert({userId:4, age:4, type:"B"})
db.people.insert({userId:5, age:14, type:"A"})
db.people.insert({userId:6, age:29, type:"C"})
db.people.insert({userId:7, age:39, type:"C"})
db.people.insert({userId:8, age:42, type:"B"})
db.people.insert({userId:9, age:56, type:"A"})
db.people.insert({userId:10, age:12, type:"A"})

69. m = function() {
emit(this.type, { age: this.age, num: 1 } );
}

70. r = function(key, values) {
var result = { age: 0, num: 0 };
values.forEach( function(value){
result.age += value.age; // age
result.num += value.num; //
} );
return result;
}

71. r = function(key, values) {
var num = 0;
var sum = 0;
values.forEach( function(value){
sum += value.age; // age
num += value.num; //
} );
return sum/num;
}

72. m = function() {
emit(this.type, { age: this.age, num: 1 } );
}
r = function(key, values) {
var result = { age: 0, num: 0 };
values.forEach( function(value){
result.age += value.age; // age
result.num += value.num; //
} );
return result;
}

73. m = function() {
emit(this.type, { age: this.age, num: 1 } );
}
r = function(key, values) {
var result = { age: 0, num: 0 };
values.forEach( function(value){
result.age += value.age; //
result.num += value.num; //
} );
return result;
}

74. f = function( key, result ){
result.avg = result.age / result.num;
return result;
}

75. > res = db.people.mapReduce( m , r ,
{ finalize : f , out : "mr_out", verbose: true });
{
"result" : "mr_out", //
"timeMillis" : 18, //
"timing" : {
"mapTime" : NumberLong(1),
"emitLoop" : 12,
"total" : 18
},
"counts" : {
"input" : 10, // 10
"emit" : 10, // 10 emit
"output" : 3 // 3
},
"ok" : 1,
}

76. > db.mr_out.find()
{ "_id" : "A",
"value" : { "age" : 106, "num" : 4, "avg" : 26.5 } }
{ "_id" : "B",
"value" : { "age" : 93, "num" : 3, "avg" : 31 } }
{ "_id" : "C",
"value" : { "age" : 102, "num" : 3, "avg" : 34 } }

77. > res = db.people.mapReduce( m , r ,
{ finalize : f , out : "mr_out", query: { age: { $gte: 20 } } });
{
"result" : "mr_out",
"timeMillis" : 35,
"counts" : {
"input" : 7, // 3
"emit" : 7,
"output" : 3
},
"ok" : 1,
}

78. > db.mr_out.find() //
{ "_id" : "A",
"value" : { "age" : 80, "num" : 2, "avg" : 40 } }
{ "_id" : "B",
"value" : { "age" : 89, "num" : 2, "avg" : 44.5 } }
{ "_id" : "C",
"value" : { "age" : 102, "num" : 3, "avg" : 34 } }

81. db.items.insert({ date: "2011-06-01", item: "apple", price: 100 })
db.items.insert({ date: "2011-06-01", item: "banana", price: 200 })
db.items.insert({ date: "2011-06-01", item: "apple" , price :100})
db.items.insert({ date: "2011-06-02", item: "orange", price: 50 })
db.items.insert({ date: "2011-06-02", item: "orange", price: 50 })
db.items.insert({ date: "2011-06-02", item: "apple", price: 100 })

82. m = function() { emit(this.item, this.price); }
r = function(key,values) {
var result = 0;
values.forEach( function(value){ result += value } );
return result;
}
> res = db.items.mapReduce( m, r, { query: {date: "2011-06-01"} ,
out: {replace: "mr_out2"}} );
{
"result" : "mr_out2",
"timeMillis" : 10,
"counts" : {
"input" : 3,
"emit" : 3,
"output" : 2
},
"ok" : 1,
}
>db.mr_out2.find()
{ "_id" : "apple", "value" : 200 }
{ "_id" : "banana", "value" : 200 }

83. > res = db.items.mapReduce( m, r,
{ query: {date: "2011-06-02"} , out: {reduce: "mr_out2"}} );
{
"result" : "mr_out2",
"timeMillis" : 23,
"counts" : {
"input" : 3,
"emit" : 3,
"output" : 3
},
"ok" : 1,
}
> db.mr_out2.find()
{ "_id" : "apple", "value" : 300 } //
{ "_id" : "banana", "value" : 200 } //
{ "_id" : "orange", "value" : 100 } //