Redis and Ohm presented by Mark Cotner to Atlanta Ruby Users group on June 9, 2010

1. Mark Cotner
Redis and Ohm
June 9, 2010

2. Mark Cotner
Redis and Ohm
June 9, 2010
Atlanta Ruby Users Group

3. It’s good to be back
This is my 4th presentation
I noticed on our history many of my presentations were
remembered, but the presenter(me) was forgotten
I guess that means the content really came across well,
but the presenter just wasn’t memorable enough :)
I missed you!
I’m awksedgreep on IRC, Twitter, etc

4. Redis
Well beyond a simple Key-Value Store
Has data structures programmers are already familiar
with: Arrays, Hashes, Queues, and much much more
Interacting with the “DB” is no different in most cases
than interacting with these data structures
Written in C for speed

5. Community
Redis license is BSD
Very active community on the mailing list and IRC
(#redis on freenode)
Fast moving project. Features are requested very often
and implemented quickly.
Very stable in spite of rapid change.
Strong client support in Ruby with redis-rb and em-
redis
ORM support with Ohm, redis-objects and
DataMapper

6. Lets talk Patterns
Redis is a database that thinks like a programmer
Publish/Subscribe
Producer/Consumer(w or w/o Blocking Queues)
Actor
Arrays
Lists/Sets
Sorted Lists/Sets(dual-indexed lists)
Object Properties by Primary Key(using Hashes, similar
to the Active Record pattern)
Sequence

7. Data Structures in Redis
Key/Value Pairs(not to be confused with redis hash)

8. Data Structures in Redis
Hash (not to be confused with key/value pairs)

9. Data Structures in Redis
Arrays/Queues

10. Data Structures in Redis
Sequences and Unsorted Sets

11. Data Structures in Redis
Sorted Sets and Time Series Data

12. Redis and Ruby
redis-rb - Widely used redis gem
em-redis - Event Machine(async) redis gem
Ohm - Object Relational Mapper for Redis, which now
uses redis hashes
resque - Relatively simple producer/consumer
background workers using redis
redis-TextSearch - Full text searching for AR using redis

13. Redis and Ruby continued
redis-store - Session and cache store for Rack/Rails/
Sinatra
Redis::Objects - Integrates with existing ORM, provides
a more OOP style functionality to redis
dm-redis-adapter - Full DataMapper functionality for
redis(Yes, it will work in Rails 3.0)
redactor - Actor Pattern on redis
more?

14. redis-rb
Just reached 2.0 milestone
Supports all major redis features through 2.0 including
Hashes
Thread Safe(with :thread_safe => true flag)
Very easy to use

15. Ohm - ORM for Redis
Has a redis feel to it (Person[1] vs Person.find(1))
Uses hashes for attributes now, extremely fast
Supports simple data validations
Allows relations to be stored as sets or lists(collection)

16. Ohm - Fun with Patterns
Group
ToDo Person
Person
Person
Task
Task
Task

17. Creating the Model in Ohm

18. Working with the Model

19. More . . .
Lets try an atomic operation
Take 1 task from the group todo queue and
assign it to a Person.

20. Future of Redis
Commercial Support - Likely from VMWare
VM - Indexes will be stored in memory, data will be
written to disk
UDP - Many operations will be supported by
lightweight UDP
Performance - Seems like antirez finds a performance
enhancement every few days
Commands - New requests for commands come in all
the time and seem to be implemented quickly if they
make sense.

21. Questions?