Persistence Smoothie: Blending SQL and NoSQL (RubyNation Edition)

Michael Bleigh Persistence Intridea, Inc. Smoothie Blending SQL and NoSQL photo by Nikki L. via Flickr Saturday, April 10, 2010

Saturday, April 10, 2010

present.ly Saturday, April 10, 2010

The Buzz Saturday, April 10, 2010

You’ve (probably) heard a lot about NoSQL Saturday, April 10, 2010

NoSQL is a new way to think about persistence Saturday, April 10, 2010

Atomicity Consistency Isolation Durability Saturday, April 10, 2010

Denormalization Eventual Consistency Schema-Free Horizontal Scale Map Reduce Saturday, April 10, 2010

Map Reduce • Massively parallel way to process large datasets • First you scour data and “map” a new set of data • Then you “reduce” the data down to a salient result Saturday, April 10, 2010

map = function() { this.tags.forEach(function(tag) { emit(tag, {count: 1}); }); } reduce = function(key, values) { var total = 0; for (var i = 0; i < values.length; i++) { total += values[i].count; return {count: total}; } Saturday, April 10, 2010

NoSQL tries to scale (more) simply Saturday, April 10, 2010

NoSQL is going mainstream Saturday, April 10, 2010

New York Times Business Insider BBC ShopWiki GitHub Meebo Disqus SourceForge Sony Digg Saturday, April 10, 2010

...but not THAT mainstream. Saturday, April 10, 2010

A word of caution... Saturday, April 10, 2010

sn’t d oe s QL wait oS , it N s le ep NoSQL can divide by zero NoSQL to infin counte ity, twi d ce Saturday, April 10, 2010

NoSQL is a (growing) collection of tools, not a new way of life Saturday, April 10, 2010

The Ecosystem Saturday, April 10, 2010

Key-Value Stores • Voldemort • Redis • Tokyo Cabinet • Riak • MemcachedDB Saturday, April 10, 2010

Document Stores • MongoDB • Riak • CouchDB • FleetDB Saturday, April 10, 2010

Column(ish) Stores • Cassandra • HBase Saturday, April 10, 2010

Graph Databases • Neo4j • HypergraphDB • InfoGrid Saturday, April 10, 2010

When should I use this stuff? Saturday, April 10, 2010

Complex, slow joins for “activity stream” Saturday, April 10, 2010

Complex, slow joins for “activity stream” Denormalize, use Key-Value Store Saturday, April 10, 2010

Variable schema, vertical interaction Saturday, April 10, 2010

Variable schema, vertical interaction Document Database or Column Store Saturday, April 10, 2010

Modeling deep relationships Saturday, April 10, 2010

Modeling deep relationships Graph Database Saturday, April 10, 2010

NoSQL solves real scalability and data design issues Saturday, April 10, 2010

Ben Scofield bit.ly/state-of-nosql Saturday, April 10, 2010

Ready to go? Saturday, April 10, 2010

Just one problem... Saturday, April 10, 2010

Your data is already in a SQL database Saturday, April 10, 2010

So now we need to ask the question... Saturday, April 10, 2010

Yeah, it blends. Saturday, April 10, 2010

The “Hard” Way: Do it by hand. Saturday, April 10, 2010

class Post include MongoMapper::Document key :title, String key :body, String key :tags, Array key :user_id, Integer def user User.find_by_id(self.user_id) end def user=(some_user) self.user_id = some_user.id end end class User < ActiveRecord::Base def posts(options = {}) Post.all({:conditions => {:user_id => self.id}}.merge(options)) end end Saturday, April 10, 2010

Pros & Cons • Simple, maps to your domain • Works for small, simple ORM intersections • MUCH simpler in Rails 3 • Complex relationships are a mess • Makes your models fat • As DRY as the ocean Saturday, April 10, 2010

The “Easy” Way: DataMapper Saturday, April 10, 2010

DataMapper • Generic, relational ORM • Speaks pretty much everything you’ve ever heard of • Implements Identity Map • Module-based inclusion Saturday, April 10, 2010

DataMapper.setup(:default, "mysql://localhost") DataMapper.setup(:mongodb, "mongo://localhost/posts") class Post include DataMapper::Resource def self.default_repository_name; :mongodb; end property :title, String property :body, String property :tags, Array belongs_to :user end class User include DataMapper::Resource property :email, String property :name, String has n, :posts end Saturday, April 10, 2010

Pros & Cons • The ultimate Polyglot ORM • Simple relationships between persistence engines are easy • Jack of all trades, master of none • Perpetuates (sometimes) false assumptions • Legacy stuﬀ is in ActiveRecord anyway Saturday, April 10, 2010

Show and Tell: Social Storefront Saturday, April 10, 2010

The Application • Dummy version of a store that lets others “follow” your purchases (like a less creepy version of Blippy) • Four requirements: • users • purchasing • listings • social graph Saturday, April 10, 2010

Users • I already have an authentication system • I’m happy with it • It’s Devise and ActiveRecord • Stick with SQL Saturday, April 10, 2010

Purchasing • Users need to be able to purchase items from my storefront • I can’t lose their transactions • I need full ACID • SQL Again Saturday, April 10, 2010

Social Graph • I want activity streams and one and two way relationships • I need speed • I don’t need consistency • I’ll use Redis Saturday, April 10, 2010

Product Listings • I am selling both books about Ruby and movies about zombies • They have very diﬀerent properties • Products are relatively non- relational • I’ll use MongoDB Saturday, April 10, 2010

Demo and Walkthrough Saturday, April 10, 2010

Wrapping Up Saturday, April 10, 2010

These systems can (and should) live and work together Saturday, April 10, 2010

Most important step is to actually think about data design Saturday, April 10, 2010

When you have a whole bag of tools, things stop looking like nails Saturday, April 10, 2010

@mbleigh Saturday, April 10, 2010

Questions? Saturday, April 10, 2010

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Persistence Smoothie: Blending SQL and NoSQL (RubyNation Edition)

by Michael Bleigh on Apr 10, 2010

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Persistence Smoothie: Blending SQL and NoSQL (RubyNation Edition) Presentation Transcript