Vagmi Mudumbai introduces themselves and provides an overview of MongoDB. Key points include: - MongoDB is a NoSQL database that uses documents with dynamic schemas, indexing, ad-hoc queries, and embedded documents and arrays. - It stores data in BSON format and supports data types like dates, binary data, and regexes. Complex queries can be performed on fields within documents. - Documents can be inserted, updated, sorted, paginated, and indexed. MapReduce can be used to generate reports from collections.

1. Introducing
Vagmi Mudumbai
(vagmi@artha42.com)

2. Who am I?

3. Who am I?
var person = {name: “Vagmi Mudumbai”, type: ”hacker”
hacks_on: [“artha42”,”chennaigeeks”],
uses: [“mongodb”,”rails”,”sinatra”]};
db.people.save(person);

4. A bit about NoSQL

5. Indexing Ad-ho
c Quer
tor age ies
SO NS
B
M ap/Reduce -place U pdates
In
Auto
Shard Repli
ing catio
n
GridFS
What is it about

6. It makes us a super hero

7. BSON Storage
var person = {name: “Vagmi Mudumbai”, type: ”hacker”
hacks_on: [“artha42”,”chennaigeeks”],
uses: [“mongodb”,”rails”,”sinatra”]};
db.people.save(person);
http://bsonspec.org/
Binary
Supports datatypes like
• Date
• Bindata
• Regexs

8. Querying
var person = {name: “Vagmi Mudumbai”, type: ”hacker”
hacks_on: [“artha42”,”chennaigeeks”],
uses: [“mongodb”,”rails”,”sinatra”],
age: 30,
location: {city: “chennai”}};
db.people.save(person);

9. Querying
var person = {name: “Vagmi Mudumbai”, type: ”hacker”
hacks_on: [“artha42”,”chennaigeeks”],
uses: [“mongodb”,”rails”,”sinatra”],
age: 30,
location: {city: “chennai”}};
db.people.save(person);
db.people.find({type: “hacker”});

10. Querying
var person = {name: “Vagmi Mudumbai”, type: ”hacker”
hacks_on: [“artha42”,”chennaigeeks”],
uses: [“mongodb”,”rails”,”sinatra”],
age: 30,
location: {city: “chennai”}};
db.people.save(person);
db.people.find({type: “hacker”});
db.people.find({uses: “rails”}); // can search within tags

11. Querying
var person = {name: “Vagmi Mudumbai”, type: ”hacker”
hacks_on: [“artha42”,”chennaigeeks”],
uses: [“mongodb”,”rails”,”sinatra”],
age: 30,
location: {city: “chennai”}};
db.people.save(person);
db.people.find({type: “hacker”});
db.people.find({uses: “rails”}); // can search within tags
db.people.find({age: {$gt: 25}}); // can do mathematics

12. Querying
var person = {name: “Vagmi Mudumbai”, type: ”hacker”
hacks_on: [“artha42”,”chennaigeeks”],
uses: [“mongodb”,”rails”,”sinatra”],
age: 30,
location: {city: “chennai”}};
db.people.save(person);
db.people.find({type: “hacker”});
db.people.find({uses: “rails”}); // can search within tags
db.people.find({age: {$gt: 25}}); // can do mathematics
db.people.find({“location.city”:”chennai”}); //can search
// within docs

13. Querying
var person = {name: “Vagmi Mudumbai”, type: ”hacker”
hacks_on: [“artha42”,”chennaigeeks”],
uses: [“mongodb”,”rails”,”sinatra”],
age: 30,
location: {city: “chennai”}};
db.people.save(person);
db.people.find({type: “hacker”});
db.people.find({uses: “rails”}); // can search within tags
db.people.find({age: {$gt: 25}}); // can do mathematics
db.people.find({“location.city”:”chennai”}); //can search
// within docs
db.people.find().sort({age:1}).skip(10).limit(10) //pagination

14. Indexing
var person = {name: “Vagmi Mudumbai”, type: ”hacker”
hacks_on: [“artha42”,”chennaigeeks”],
uses: [“mongodb”,”rails”,”sinatra”]};
db.people.save(person);
db.people.ensureIndex({“type”:1});
db.people.ensureIndex({“uses”:1});
db.people.getIndexes(); // returns a list of indexes
No different from a standard database
Can index on multiple fields
Can index into sub documents and arrays
_id is automatically indexed

15. Updates
var person = {name: “Vagmi Mudumbai”, type: ”hacker”
hacks_on: [“artha42”,”chennaigeeks”],
uses: [“mongodb”,”rails”,”sinatra”],
age: 30,
location: {city: “chennai”}};
db.people.save(person);

16. Updates
var person = {name: “Vagmi Mudumbai”, type: ”hacker”
hacks_on: [“artha42”,”chennaigeeks”],
uses: [“mongodb”,”rails”,”sinatra”],
age: 30,
location: {city: “chennai”}};
db.people.save(person);
var p = db.people.findOne({type: “hacker”});
p.age = 29;
db.people.save(p); //updates the above record

17. Updates
var person = {name: “Vagmi Mudumbai”, type: ”hacker”
hacks_on: [“artha42”,”chennaigeeks”],
uses: [“mongodb”,”rails”,”sinatra”],
age: 30,
location: {city: “chennai”}};
db.people.save(person);
var p = db.people.findOne({type: “hacker”});
p.age = 29;
db.people.save(p); //updates the above record
var p = db.people.findOne({type: “hacker”});
db.people.update({_id: p._id},{$inc:{age:1}});

18. Updates
var person = {name: “Vagmi Mudumbai”, type: ”hacker”
hacks_on: [“artha42”,”chennaigeeks”],
uses: [“mongodb”,”rails”,”sinatra”],
age: 30,
location: {city: “chennai”}};
db.people.save(person);
var p = db.people.findOne({type: “hacker”});
p.age = 29;
db.people.save(p); //updates the above record
var p = db.people.findOne({type: “hacker”});
db.people.update({_id: p._id},{$inc:{age:1}});
var p = db.people.findOne({type: “hacker”});
db.people.update({_id: p._id},
{$inc:{age:1},$push:{uses: “vim”}});

19. Map/Reduce
{ url: “/blog/something”,
user_id: ObjectID(‘xxxxxx’),
date: “Sat Oct 16 2010 06:30:00 GMT+0530 (IST)” }
Source: http://cookbook.mongodb.org/patterns/unique_items_map_reduce/

20. Map/Reduce
{ url: “/blog/something”,
user_id: ObjectID(‘xxxxxx’),
date: “Sat Oct 16 2010 06:30:00 GMT+0530 (IST)” }
map = function() {
day = Date.UTC(this.date.getFullYear(),
this.date.getMonth(),this.date.getDate);
emit({day: day, user_id: this.user_id},{count: 1});
}
Source: http://cookbook.mongodb.org/patterns/unique_items_map_reduce/

21. Map/Reduce
{ url: “/blog/something”,
user_id: ObjectID(‘xxxxxx’),
date: “Sat Oct 16 2010 06:30:00 GMT+0530 (IST)” }
map = function() {
day = Date.UTC(this.date.getFullYear(),
this.date.getMonth(),this.date.getDate);
emit({day: day, user_id: this.user_id},{count: 1});
}
reduce = function(key,values){
var count=0;
values.forEach(function(v){
count+=v;
}
return {count: count}
}
Source: http://cookbook.mongodb.org/patterns/unique_items_map_reduce/

22. Map/Reduce
{ url: “/blog/something”,
user_id: ObjectID(‘xxxxxx’),
date: “Sat Oct 16 2010 06:30:00 GMT+0530 (IST)” }
map = function() {
day = Date.UTC(this.date.getFullYear(),
this.date.getMonth(),this.date.getDate);
emit({day: day, user_id: this.user_id},{count: 1});
}
reduce = function(key,values){
var count=0;
values.forEach(function(v){
count+=v;
}
return {count: count}
}
db.pageviews.mapReduce(map,reduce,{out: pageview_results});
Source: http://cookbook.mongodb.org/patterns/unique_items_map_reduce/

23. Map/Reduce (contd)
{ _id: {day: “Sat Oct 16 2010 00:00:00Z”,
user_id: ObjectId(xxx)},
count: 20}
Source: http://cookbook.mongodb.org/patterns/unique_items_map_reduce/

24. Map/Reduce (contd)
{ _id: {day: “Sat Oct 16 2010 00:00:00Z”,
user_id: ObjectId(xxx)},
count: 20}
map = function() {
emit(this,{count: 1});
}
Source: http://cookbook.mongodb.org/patterns/unique_items_map_reduce/

25. Map/Reduce (contd)
{ _id: {day: “Sat Oct 16 2010 00:00:00Z”,
user_id: ObjectId(xxx)},
count: 20}
map = function() {
emit(this,{count: 1});
}
reduce = function(key,values){
var count=0;
values.forEach(function(v){
count+=v;
}
return {count: count}
}
Source: http://cookbook.mongodb.org/patterns/unique_items_map_reduce/

26. Map/Reduce (contd)
{ _id: {day: “Sat Oct 16 2010 00:00:00Z”,
user_id: ObjectId(xxx)},
count: 20}
map = function() {
emit(this,{count: 1});
}
reduce = function(key,values){
var count=0;
values.forEach(function(v){
count+=v;
}
return {count: count}
}
db.pageview_results.mapReduce(map,reduce,
{out: pageview_results_unique});
Source: http://cookbook.mongodb.org/patterns/unique_items_map_reduce/

27. GridFS (in Ruby)
Source: http://cookbook.mongodb.org/patterns/unique_items_map_reduce/

28. GridFS (in Ruby)
@db = Mongo::Connection.new.db(“chennaigeeks”)
@fs = GridFileSystem.new(@db)
Source: http://cookbook.mongodb.org/patterns/unique_items_map_reduce/

29. GridFS (in Ruby)
@db = Mongo::Connection.new.db(“chennaigeeks”)
@fs = GridFileSystem.new(@db)
image = File.open(“me.png”)
@fs.open(“me.png”,’w’) do |f|
f.write image
end
Source: http://cookbook.mongodb.org/patterns/unique_items_map_reduce/

30. GridFS (in Ruby)
@db = Mongo::Connection.new.db(“chennaigeeks”)
@fs = GridFileSystem.new(@db)
image = File.open(“me.png”)
@fs.open(“me.png”,’w’) do |f|
f.write image
end
img = @fs.open(“me.png”,”r”) { |f| f.read }
Source: http://cookbook.mongodb.org/patterns/unique_items_map_reduce/

31. Replication (Master/Slave)
db@master /opt/mongo/bin$ ./mongod ‐‐master
db@slave /opt/mongo/bin$ ./mongod ‐‐slave ‐‐source master

32. Replication (Replica Sets)
db@node1 /opt/mongo/bin$ ./mongod ‐‐replSet myRS
db@node2 /opt/mongo/bin$ ./mongod ‐‐replSet myRS
db@node3 /opt/mongo/bin$ ./mongod ‐‐replSet myRS
db@dev /opt/mongo/bin$ ./mongo node1
MongoDB shell version: 1.6.0
connecting to: node1/test
> config = {_id: “myRS”, members : [
{_id: 0, host: “node1”},
{_id: 0, host: “node2”},
{_id: 0, host: “node3”}]}
> rs.initiate(config);
> rs.status()

33. Auto Sharding
db@node1 /opt/mongo/bin$ ./mongod ‐‐shardsvr
db@node2 /opt/mongo/bin$ ./mongod ‐‐shardsvr
db@node3 /opt/mongo/bin$ ./mongod ‐‐configsvr
db@appserver /opt/mongo/bin$ ./mongos ‐‐configdb node3

34. Auto Sharding (contd)
db@appserver /opt/mongo/bin$ ./mongo
MongoDB shell version: 1.6.0
connecting to: test
> use admin
switched to db admin
> db.runCommand({addShard : “node1”});
{ “shardadded”: “shard0000”, ”ok”: 1}
> db.runCommand({addShard : “node2”});
{ “shardadded”: “shard0001”, ”ok”: 1}
> db.runCommand(enableSharding : “mydb”)
{“ok” : 1}
> db.runCommand({ shardCollection : “mydb.people”,
key : {name : 1} });
{“ok” : 1 }

35. Any Questions?

36. vagmi@artha42.com
http://blog.chennaigeeks.com/