1. MapReduce, Geospatial Indexes,
and Other Cool Features
Kristina Chodorow

3. connecting to
your mongod

4. connecting to
your mongod
you

5. connecting to
your mongod
you
mongod

6. mongod

7. mongod

8. update insert query insert query mongod

9. mongod
driver

10. query
insert
driver

11. insert
query mongod
driver

12. insert
getlasterror
mongod
driver

13. insert
getlasterror
mongod
driver

15. replication
Dwight @ 3:15
Farallon Room

18. insert this

19. all set

23. insert this

24. all set

26. make sure two
slaves have this

30. all set

32. make sure two
slaves have this

38. > db.runCommand({
... getlasterror : 1
... })

39. > db.runCommand({
... getlasterror : 1,
... w : 3
... })

40. > db.runCommand({
... getlasterror : 1,
... w : 500
... })

41. > db.runCommand({
... getlasterror : 1,
... w : 500,
... wtimeout : 3000
... })

42. > db.runCommand({
... getlasterror : 1,
... fsync : true
... })

43. some internals

44. Operations:
insert
update
remove
query
get more

45. Operations:
insert
update
remove
query
get more

46. Operations:
insert
update
remove
query
get more

47. Operations:
insert
update
remove
query
get more

48. Operations:
insert
update
remove
query
get more

49. Operations:
insert
update
remove
query
get more

50. Operations:
insert
update
remove
query
get more

51. get help

52. $ mongo
MongoDB shell version 1.5.1
url: test
connecting to: test
type "help" for help
>

53. $ mongo
MongoDB shell version 1.5.1
url: test
connecting to: test
type "help" for help
>

54. > db.help()
DB methods:
db.addUser()
db.auth()
db.cloneDatabase()
db.commandHelp()
db.copyDatabase()
db.createCollection()
db.currentOp()
...

55. > db.foo.help()
DBCollection help
db.foo.count()
db.foo.dataSize()
db.foo.distinct()
db.foo.drop()
db.foo.dropIndex()
db.foo.dropIndexes()
...

56. > var cursor = db.foo.find()
> cursor.help()
DBQuery help
.sort()
.limit()
.skip()
.count()
.size()
...

57. http://api.mongodb.org/js

58. > db.foo.count()
40
>

59. > db.foo.count()
40
> db.foo.count

60. > db.foo.count()
40
> db.foo.count
function(x) {
return this.find(x).count();;
}
>

61. > db.foo.count()
40
> db.foo.count
function(x) {
return this.find(x).count();;
}
> var cursor = db.foo.find()
>

62. > db.foo.count()
40
> db.foo.count
function(x) {
return this.find(x).count();;
}
> var cursor = db.foo.find()
> cursor.count

63. > cursor.count
function(applySkipLimit) {
var cmd = {count : this._collection.getName()};;
if (this._query) {
if (this._special) {
cmd.query = this._query.query;;
}
else {
cmd.query = this._query;;
}
}
cmd.fields = this._fields || {};;
if (applySkipLimit) {
if (this._limit) {
cmd.limit = this._limit;;
...

64. function(x) {
// prep cmd
...
// run command
var res = this._db.runCommand(cmd);;
// return result
...
}

65. > db.runCommand({count : "foo"})
{
"n" : 40,
"ok" : 1
}
>

66. > db.runCommand({listCommands : 1})

67. > db.runCommand({listCommands : 1})
{
"commands" : {
"$eval" : {...},
"assertinfo : {...},
"authenticate" : {...},
"buildinfo" : {...},
"clean" : {...},
"clone" : {...},
"cloneCollection" : {...},
"cloneCollectionAsCapped" : {...},
"closeAllDatabases" : {...},
...

68. > db.runCommand({
... datasize : collectionName})

69. > db.runCommand({
... datasize : collectionName})
> db.runCommand({
... dbstats : 1})

70. > db.commandHelp("distinct")
help for: distinct: {
distinct : 'collection name',
key : 'a.b' }
>

71. > db.commandHelp("distinct")
help for: distinct: {
distinct : 'collection name',
key : 'a.b' }
> db.commandHelp
function(name) {
var c = {};;
c[name] = 1;;
c.help = true;;
return this.runCommand(c).help;;
}
>

72. > db.runCommand({"count" : 1,
... "help" : true})

73. > db.runCommand({"count" : 1,
... "help" : true})
help for: count: no help defined
>

74. $

75. > db.blog.posts.find(
... {_id : 123},
... {comments : 1})

76. > db.blog.posts.find(
... {_id : 123},
... {comments : {$slice : 10}})

77. > db.blog.posts.find(
... {_id : 123},
... {comments : {$slice : [20, 10]}})

78. > db.blog.posts.find(
... {_id : 123},
... {comments : {$slice : -­10}})

79. > db.blog.posts.find(
... {_id : 123},
... {comments : {$slice : [-­20, 10]}})

80. > db.blog.posts.find({
... comments : {
... date : {$gt : today},
... votes : {$gte : 10}
... }})

81. > db.blog.posts.find({
... 'comments.date' : {$gt : today},
... 'comments.votes' : {$gte : 10}
... })

82. > db.blog.posts.find({
... comments : {$elemMatch : {
... date : {$gt : today},
... votes : {$gte : 10}
... }}})

83. Types

84. minKey
maxKey

85. MapReduce

88. {
_id : 123,
name : "Fred",
email : "fred@example.com"
}
{
_id : 456,
name : "Paul",
phone : "555-­5555",
picture : BinData
}
{
_id : 789,
email : "alice@example.com",
}

89. _id 40
name 32
email 20
phone 2
picture 17
pet 3
friends 40
hobbies 6
favorites 12
notes 14

91. {
_id : 123,
name : "Fred",
email : "fred@example.com"
}

92. 1
1
1

93. _id
1
name
1
email
1

94. email

95. email

96. 12

97. cluck cluck
12

98. email
12

99. map = function() {
for (var key in this) {
emit(key, 1);;
}
}

100. reduce = function(prev, current) {
var count = 0;;
for (var egg in current) {
count += current[egg];;
}
return count;;
}

103. A B C D E F

104. A B C D E F

105. A B C D E F
_id : A, value : _id : C, value : _id : E, value :
_id : B, value : _id : D, value : _id : F, value :

106. GridFS

108. Indexes

111. > db.users.find({
... date : new Date("10/3/2010")})
> db.users.ensureIndex({
... date : 1})

112. Dates, timestamps, ObjectIds

113. indexing
Aaron @ 3:15
Niantic Room

114. Geospatial Indexes

116. > db.map.ensureIndex({location : "2d"})
>

117. > db.map.insert({location : [-­40, 78]})
>

118. > db.map.insert({location : [-­40, 78]})
> db.map.insert({location : {
... x : -­40,
... y : 78}})
>

119. > db.map.insert({location : [-­40, 78]})
> db.map.insert({location : {
... x : -­40,
... y : 78}})
> db.map.insert({location : {
... longitude : -­40,
... latitude : 78}})
>

120. > db.map.find({location : {
... $near : [-­40, 77]}})

121. > db.map.find({location : {
... $near : [-­40, 77]}})-­>limit(10)

122. > db.map.ensureIndex({
... location : "2d",
... user : 1});;

125. 1 degree of longitude at the equator:

126. 1 degree of longitude at the equator:
1 degree of longitude near the poles:

130. geospatial
Eliot @ 10:15
Gateway Room

131. please help
document stuff!
http://cookbook.mongodb.org

132. want to work on
mongodb?
http://www.10gen.com/jobs

133. thank you!
@kchodorow
http://www.snailinaturtleneck.com