Ruby &
^
Hands on with MongoDB
Austin on Rails October 27, 2009
WYNNNETHERLAND
Wednesday, October 28, 2009

Wednesday, October 28, 2009

x
No SQL?
x
Wednesday, October 28, 2009

When does NOSQL make sense?
★ Your data is stored and retrieved mainly by primary key, without
complex joins.
★ You have a non-trivial amount of data, and the thought of managing
lots of RDBMS shards and replication failure scenarios gives you the fear.
http://www.metabrew.com/article/anti-rdbms-a-list-of-distributed-key-value-stores/
Wednesday, October 28, 2009

Key value stores
Project Voldemort
me ver y cool
Ringo
Scalaris
So space
Kai
ojects in this
Dynomite
MemcacheDB
pr
ThruDB
CouchDB
Cassandra
HBase
Hypertable
Redis
Tokyo Cabinet/Tyrant
http://www.metabrew.com/article/anti-rdbms-a-list-of-distributed-key-value-stores/
Wednesday, October 28, 2009

Tokyo Cabinet: Popular with Rubyists, Big in Japan
Wednesday, October 28, 2009

Tokyo Cabinet: Popular with Rubyists, Big in Japan
★ Lightning fast
★ Works best for at objects
★ Tokyo Tyrant for network access
http://www.igvita.com/2009/02/13/tokyo-cabinet-beyond-key-value-store/
Wednesday, October 28, 2009

More document-oriented solutions
Wednesday, October 28, 2009

Wednesday, October 28, 2009

CouchDB
Apache CouchDB is a distributed, fault-tolerant and
schema-free document-oriented database accessible via
a RESTful HTTP/JSON API.
http://couchdb.apache.org/
Wednesday, October 28, 2009

Erlang + Javascript
Wednesday, October 28, 2009

Map + reduce
Wednesday, October 28, 2009

Very cool
Wednesday, October 28, 2009

Plenty o’ Ruby to go around
Wednesday, October 28, 2009

Ruby libraries for CouchDB
CouchRest
Basic model
om t he
RelaxDB
Fr ils talk
on Ra
CouchPotato
CouchFoo A ustin
ActiveCouch
http://www.slideshare.net/brianthecoder/couchdb
Wednesday, October 28, 2009

Document stores:
a lmost*
Throw out everything
you learned about DB design
* more on this later
Wednesday, October 28, 2009

SQL CouchDB
Prede ned, explicit schema Dynamic, implicit schema
Collection of named documents with varying
Uniform tables of data
structure
Normalized. Objects spread across tables. Denormalized. Docs usually self contained. Data
Duplication reduced. often duplicated.
Must know schema to read/write a complete
Must know only document name
object
Dynamic queries of static schemas Static queries of dynamic schemas
http://damienkatz.net/files/What is CouchDB.pdf
http://damienkatz.net/files/What is CouchDB.pdf
Wednesday, October 28, 2009

SQL CouchDB
Prede ned, explicit schema Dynamic, implicit schema
Collection of named documents with varying
Uniform tables of data
structure
Normalized. Objects spread across tables.
Duplication reduced.
TheDenormalized. Docs usually selfdetails
devil'soften duplicated.contained. Data
in the
Must know schema to read/write a complete
Must know only document name
object
Dynamic queries of static schemas Static queries of dynamic schemas
http://damienkatz.net/files/What is CouchDB.pdf
http://damienkatz.net/files/What is CouchDB.pdf
Wednesday, October 28, 2009

Wednesday, October 28, 2009

because this is BIG
Wednesday, October 28, 2009

Wednesday, October 28, 2009

Runs like Hayes.
Hits like Mays.
Wednesday, October 28, 2009

MongoDB
x
Wednesday, October 28, 2009

Let's just skip to here already!
x
Wednesday, October 28, 2009

Introducing
★ Built For Speedcan be very fast
★ Dynamic Queries and Indexes
★ Replication and Failover
★ Sharding
★ Map / Reduce
Wednesday, October 28, 2009

MongoDB is great for
★ Websites
★ Caching
★ High volume, low value
★ High scalability stash the hash
★ Storage of program objects and JSON
Wednesday, October 28, 2009

Not as great for
★ Highly transactional
★ Ad-hoc business intelligence
★ Problems requiring SQL
Wednesday, October 28, 2009

Installation
★ mkdir -p /data/db
★ download pre-built for OSX and unzip to /usr/local/
★ cp -R /usr/local/pathtomongo/bin /usr/local/bin
Ruby driver for MongoDB
★ sudo gem install mongo
Native C
★ sudo gem install mongo_ext extensions ( go turbo! )
★ sudo gem install mongo_mapper
Wednesday, October 28, 2009

what's in the box?
Contents of mongo/bin
★ mongod - The MongoDB server
★ mongo - the JavaScript interactive shell
★ mongoexport - export data as JSON or csv
★ mongoimport - As advertised
was?
★ mongodump - Like mysqldump why? What did you think it
★ mongorestore - Restore from mongodump les
★ mongos - Auto-sharding module (getting better with every build)
Wednesday, October 28, 2009

Some new terms
Wednesday, October 28, 2009

When I say
database
Wednesday, October 28, 2009

When I say think
database database
Wednesday, October 28, 2009

When I say think
database database
Well that one isn't new...
Wednesday, October 28, 2009

Databases in MongoDB
★ Made up of multiple collections
★ Are created on-the- y when rst referenced
Wednesday, October 28, 2009

When I say
collection
Wednesday, October 28, 2009

When I say think
collection table
Wednesday, October 28, 2009

Collections in MongoDB
★ Schema-less but typed!
★ For grouping documents into smaller query sets (speed)
★ Indexable by one or more key
★ Are created on-the- y when rst referenced
★ Capped collections: Fixed size, older records dropped after limit
reached
Wednesday, October 28, 2009

When I say
document
Wednesday, October 28, 2009

When I say think
document record or row
Wednesday, October 28, 2009

Document
★ Stored in a collection
★ Can have _id key that works like primary keys in MySQL
★ Supports relationships: subdocument or db reference
Wednesday, October 28, 2009

Document Storage (BSON)
{ author: 'joe',
created: Date('03-28-2009'),
title: 'Yet another blog post',
text: 'Here is the text...',
tags: [ 'example', 'joe' ],
comments: [ { author: 'jim', comment: 'I disagree' },
{ author: 'nancy', comment: 'Good post' }
]
}
http://www.mongodb.org/display/DOCS/BSON
Wednesday, October 28, 2009

Document Storage (BSON)
{ author: 'joe',
created: Date('03-28-2009'),
title: 'Yet another blog post',
text: 'Here is the text...',
tags: [ 'example', 'joe' ],
comments: [ { author: 'jim', comment: 'I disagree' },
{ author: 'nancy', comment: 'Good post' }
]
}
Sure wish JSON did this...
http://www.mongodb.org/display/DOCS/BSON
Wednesday, October 28, 2009

Document Storage (BSON) B is for Binary
{ author: 'joe',
created: Date('03-28-2009'),
title: 'Yet another blog post',
text: 'Here is the text...',
tags: [ 'example', 'joe' ],
comments: [ { author: 'jim', comment: 'I disagree' },
{ author: 'nancy', comment: 'Good post' }
]
}
Sure wish JSON did this...
http://www.mongodb.org/display/DOCS/BSON
Wednesday, October 28, 2009

That looks like JSON
Wednesday, October 28, 2009

So does this
jason.to_json
Wednesday, October 28, 2009

Where's the Ruby?
Wednesday, October 28, 2009

Querying
db.collection.find({'first_name': 'John'}) # finds all Johns
db.collection.find({'first_name': /^wynn/i}) # regex
db.collection.find_first({'_id':1}) # finds first with _id of 1
db.collection.find({'age': {'$gte': 21}}) # finds possible drinkers
db.collection.find({'author.first_name':'John'}) # subdocument
db.collection.find({$where:'this.age >= 6 && this.age <= 18'})
Wednesday, October 28, 2009

More
Querying
$in, $nin, $all, $ne, $gt, $gte, $lt, $lte, $size, $where
:fields (like :select in active record)
:limit, :offset for pagination
:sort ascending or descending [['foo', 1], ['bar', -1]]
count and group (uses map/reduce)
db.collection.mapReduce(mapfunction,reducefunction[,options]);
Wednesday, October 28, 2009

10 Gen projects on the hub
★ mongo-ruby-driver http://github.com/mongodb/mongo-ruby-
driver
★ mongorecord http://github.com/mongodb/mongo-activerecord-
ruby
Wednesday, October 28, 2009

MongoMapper from @jnunemaker
★ Mongo is not MySQL
★ DSL for modeling domain should also teach you Mongo
★ It sounded fun
★ Just released version 0.5.6
Wednesday, October 28, 2009

MongoMapper from @jnunemaker
★ Mongo is not MySQL
★ DSL for modeling domain should also teach you Mongo
★ It sounded fun
★ Just released version 0.5.6
I voted for "Nunemapper"
Wednesday, October 28, 2009

Features
★ Typecasting
★ Callbacks (ActiveSupport Callbacks)
★ Validations
★ Connection and database can differ per document
★ Create and Update with single or multiple
★ Delete and Destroy and _all counterparts
Be careful. Ordering can be tricky.
★ Find: id, ids, :all, : rst, :last
★ Associations
Wednesday, October 28, 2009

Example
class User
include MongoMapper::Document
key :name, String, :required => true, :length => 5..100
key :email, String, :required => true, :index => true
key :age, Integer, :numeric => true
key :active, Boolean, :default => true
one :address
many :articles
end
Included as module, not subclassed
(this may change soon).
class Address
include MongoMapper::Document
key :street, String
key :city, String
key :state, String, :length => 2
key :zip, Integer, :numeric => true, :length => 5
end
Wednesday, October 28, 2009

MongoDB fun
★ Capped collections (think memcache, actually used for replication)
★ Upserts db.collection.update({'_id':1}, {'$inc':
{'views':1}})
★ Multikeys (think tagging and full text search)
★ GridFS and auto-sharding
Wednesday, October 28, 2009

So, is it ready for Prime Time?
★ Disqus
★ SourceForge
★ TweetCongress, GovTwit -- Floxee.com
★ TweetSaver.com
★ Mozilla Ubiquity Herd
Ask these folks!
Wednesday, October 28, 2009

Lessons learned in production the fine print
★ The laws of computing are still in effect
★ Indexes are important no matter what the salesman told ya about
performance
★ Data modeling. Deep or Wide? The answer is yes!
★ MongoDB and MongoMapper are in active development
Very responsive yet very volatile changes!
Wednesday, October 28, 2009

How can you help?
★ We need an awesome admin GUI
★ Port some plugins (might get easier with ActiveModel support
coming soon)
★ Build something cool
Wednesday, October 28, 2009

Resources an d thanks for having me!
http://mongodb.org
http://www.10gen.com the very cool company behind MongoDB
http://groups.google.com/group/mongomapper
http://groups.google.com/group/mongodb-user
http://squeejee.com
Questions? I'm @pengwynn on Twitter
http://wynnnetherland.com
the very new blog
Wednesday, October 28, 2009