Introduction to MongoDB and Ruby

The California Gold Rush of 1849

MongoDB: Ruby's Mother Lode

Ruby and MongoDB are well matched

Outfitting Beyond Your Pickaxe Book

Mac OS X- MongoDB Quickstart

    $ brew update
    $ brew install mongodb
    $ mongod
    

Ruby driver setup - Ruby Language Center

    $ gem install mongo
    $ gem install bson_ext
    

    gem 'mongo'
    gem 'bson_ext'
    

RubyMine

IDE includes support for Mongoid and MongoDB

Let's Dig In

Twitter friends - load users

    require 'mongo'
    require 'httpclient'
    require 'json'

    screen_name = ARGV[0] || 'garymurakami'
    friends_ids_uri = "https://api.twitter.com/1/friends/ids.json?cursor=-1&screen_name=#{screen_name}"
    friend_ids = JSON.parse(HTTPClient.get(friends_ids_uri).body)['ids']
    

a few lines of Ruby gets and parses JSON data from the web - twitter API

• libraries/gems
  • mongo, bson, bson_ext
  • httpclient, json
• language capability
  • method call chaining

Twitter friends - load users (continued)

    connection = Mongo::Connection.new
    db = connection['twitter']
    collection = db['users']

    friend_ids.each_slice(100) do |ids| # best practices
        users_lookup_uri = "https://api.twitter.com/1/users/lookup.json?user_id=#{ids.join(',')}"
        response = HTTPClient.get(users_lookup_uri)

        docs = JSON.parse(response.body) # high-level objects - Array of Hashes
        docs.each{|doc| doc['_id'] = doc['id']} # user supplied _id
        collection.insert(docs, :safe => true) # no schema! - bulk insert - best practices
    end
    puts "users:#{collection.count}"
    

a small number of lines load JSON data from the web into a collection

• DB connection, database, collection
• docs - Ruby Array of Hashes from JSON parsing
• doc primary _id set by user or driver
• collection bulk insert and safe mode
• collection count

Hitting Paydirt

Twitter top 10 users by followers count

    users = Mongo::Connection.new['twitter']['users']

    users.find({}, :sort => { followers_count: -1 }, :limit => 10).each do |doc|
        puts doc.values_at('followers_count', 'screen_name').join("\t")
    end
    

a simple query with sort and limit

• find - cursor enumerable
• expressed in Ruby code
• driver serializes into BSON and Mongo Wire Protocol
• no text language generation or parsing

    1409213	Dropbox
    25092	MongoDB
    9074	oscon
    8148	railsconf
    7302	spf13
    4374	10gen
    2259	kchodorow
    1925	rit
    1295	dmerr
    1148	aaronheckmann
    

Digging Deeper

Twitter - load tweets (simplified)

    db = Mongo::Connection.new['twitter']
    users = db['users']
    tweets = db['tweets']
    tweets.ensure_index('user.id') # dot notation to specify subfield

    users.find({}, {fields: {id: true, screen_name: true, since_id: true}}).each do |user|
        twitter_user_timeline_uri =  "https://api.twitter.com/1/statuses/user_timeline.json?user_id=#{user['id']}&count=200&include_rts=true&contributor_details=true"
        twitter_user_timeline_uri += "since_id=#{user['since_id']}" if user['since_id']
        response = HTTPClient.get(twitter_user_timeline_uri)

        docs = JSON.parse(response.body) # high-level objects
        docs.each{|doc| doc['_id'] = doc['id']} # user supplied _id
        tweets.insert(docs, :continue_on_error => true) # bulk insert
        users.update({_id: user['_id']}, {'$set' => {'since_id' => docs.last['id']}})
        puts tweets.count(:query => {'user.id' => user['id']})
    end
    puts "tweets:#{tweets.count}"
    

a small number of lines loads and records tweets

• indexing - secondary indexes
• retrieving a subset of fields
• update - record since_id
• count with query selector

Twitter top 10 tweets for MongoDB by retweet_count

    tweets = Mongo::Connection.new['twitter']['tweets']

    screen_name = 'MongoDB'

    tweets.find({'user.screen_name' => screen_name}, :sort => { retweet_count: -1 }, :limit => 10).each do |doc|
        puts doc.values_at('retweet_count', 'text').join("\t")
    end
    

a simple query with a query selector, sort and limit

• MongoDB query language
• dot notation for nested sub-document fields

    172	#MongoDB v2.2 released http://t.co/sN6Rzc7D
    77	#mongoDB2dot2 officially released, w/ Advanced Aggregation Framework, Multi-Data Center Deployment + 600 new features http://t.co/DMSdWGwN
    59	Announcing free  online MongoDB classes. http://t.co/RIoAb7l7
    30	RT @jmikola: Introducing mongoqp: a frontend for #MongoDB's query profiler https://t.co/ROCSzs6W
    29	Sign up for free online MongoDB courses starting in October http://t.co/Im68Q4NM
    24	1,000+ have signed up for free MongoDB training since the courses were announced today http://t.co/oINxfH1t
    22	How Disney built a big data platform on a startup budget using MongoDB. http://t.co/8qW5yc7T
    21	#mongoDB2dot2, available for download. http://t.co/kcGhUDhI
    19	MongoDB Sharding Visualizer http://t.co/onIG08jv another product of #10genLabs
    16	MongoDB Java Driver 2.9.0 released http://t.co/UDvZoAYV
    

Striking Gold

BSON - Binary JSON

http://bsonspec.org/

        {"BSON": ["awesome", 5.05, 1986]}	→
        "\x31\x00\x00\x00
        \x04BSON\x00
        &\x00\x00\x00
        \x020\x00\x08\x00\x00\x00awesome\x00
        \x011\x00333333\x14@
        \x102\x00\xc2\x07\x00\x00
        \x00
        \x00"
    

• request payload includes query and documents to server
• response and documents to client

fast - no parsing, no server-side data repackaging to disk

Replica Sets

multiple database server nodes

one primary member, many secondary members

• high availability
  • auto-failover via election by majority
  • write concern
• read scaling - read preferences
• backups
• upgrades
• use (hidden) replica for secondary workload
  • analytics
  • data-processing
  • integration with external systems

Sharding

• horizontal scaling across multiple nodes
  • automatic balancing
  • failover - each shard can be a replica set
• shard key - partition by range
• chunks up to 64MB
• routing processes - mongos

Nuggets - More MongoDB Features

• mongo shell
  • JavaScript, native for server-side processing
  • highly recommended for development and administration
• map/reduce
  • batch processing of data and aggregation operations
• aggregation framework
  • calculate aggregated values without having to use map-reduce
  • pipeline, operators, expressions
• GridFS
  • specification for storing large files in MongoDB chunks usually 256KB
• Capped collections
  • fixed sized collections that have a very high performance auto-FIFO age-out feature
• Hadoop connector
  • reading MongoDB data into Hadoop as well as writing map/reduce results back out

Full-Bore Mining with Web Frameworks

Ruby on Rails, Sinatra, etc.

MongoMapper ODM - John Nunemaker

        class User
            include MongoMapper::Document
            key :name, String
            key :age,  Integer
            many :hobbies
        end

        class Hobby
            include MongoMapper::EmbeddedDocument
            key :name,    String
            key :started, Time
        end

        user = User.new(:name => 'Brandon')
        user.hobbies.build(:name => 'Programming', :started => 10.years.ago)
        user.save!

        User.where(:name => 'Brandon').first
    

• simplified model different from ActiveRecord
• good example for Ruby metaprogramming
• small is beautiful

Mongoid ODM - Durran Jordan

        class Artist
            include Mongoid::Document
            field :name, type: String
            embeds_many :instruments
        end

        class Instrument
            include Mongoid::Document
            field :name, type: String
            embedded_in :artist
        end

        syd = Artist.where(name: "Syd Vicious").between(age: 18..25).first
        syd.instruments.create(name: "Bass")
        syd.with(database: "bands", session: "backup").save!
    

• documents
• persistence
• querying
• ActiveModel relations (belongs_to, has_one, has_many, habtm)
• nested attributes
• validation
• indexing
• extras

Moped driver - Bernerd Schaefer

        session = Moped::Session.new([ "127.0.0.1:27017" ])
        session.use "echo_test"

        session.with(safe: true) do |safe|
        safe[:artists].insert(name: "Syd Vicious")
        end

        session[:artists].find(name: "Syd Vicious").update(:$push => { instruments: { name: "Bass" }})
    

a MongoDB driver for Ruby which exposes a simple, elegant, and fast API

• fast, thread-safe, uses sidekiq
• pure Ruby - no C extensions
• metaprogramming - extends standard classes
• Ruby > 1.9
• used by Mongoid 3

JRuby

• The Best of the JVM
  • High performance
  • Real threading - multi-core parallelism
  • Vast array of libraries
• It's Just Ruby
  • Ruby 1.8.7 & 1.9.2 compatible
  • Both versions in single install
• bson_java
• Mongo Hadoop connector

Fool's Gold - RDBMS Case Study

Adobe Photoshop Lightroom

"Lightroom 3 Catalog.lrcat"

• 0.5 GB
• 66 Sqlite3 tables
• 20 tables with column image INTEGER
• can be loaded with 40 lines of Ruby
• can be reduced to 1 image collection

The cost of using RDBMS for persistence

• RDBMS flattened and normalized our data into rigid tables
• RDBMS costs O(10**6) - O(1000000) and more with many joins
  • Memory O(10**9/sec) - O(1000000000)
  • RDBMS O(10**3/sec) - O(1000)

The Mother Lode

MongoDB Summary

• replica sets for high availability
• sharded clusters for scaling
• very high performance
  • secondary indices
  • BSON is fast for transfer, storage, queries
  • server-side processing
    • map-reduce, aggregation
    • Hadoop connector
• very low cost - open source - community

MongoDB Conclusion

• enjoyable software development
  • 10gen and Moped Ruby drivers
  • MongoMapper and Mongoid ODMs
  • no schema migrations forced
• well-matched to programming languages
  • bigger data
  • Ruby and objects

Announcement and Questions

MongoDB and Ruby Blogging Contest

Objective Write about best practices for using MongoDB with Ruby. Post your blog posts in the comments section of this blog post by October 10 to be entered to win.

Google: mongodb and ruby blogging contest

Thank you

and may you strike gold

                        {
                            name: "Gary J. Murakami, Ph.D.",
                            title: "Lead Engineer and Ruby Evangelist",
                            company: "10gen (the MongoDB company)",
                            phone: "1-866-237-8815 x8015",
                            mobile: "1-908-787-6621",
                            email: "gary.murakami@10gen.com",
                            im: "gjmurakami (AIM)",
                            twitter: "@GaryMurakami",
                            blog: "grayghostwriter.blogspot.com",
                            website: "www.nobell.org",
                            linkedin: "www.linkedin.com/pub/gary-murakami/1/36a/327",
                            facebook: "facebook.com/gary.j.murakami"
                        }
    

• https://github.com/gjmurakami-10gen/talk-mother-lode
• git://github.com/gjmurakami-10gen/talk-mother-lode.git
• MongoDB
• Ruby Language Center
• Github mongodb/mongo-ruby-driver