1. Apache
CouchDB
Saturday, 21 March 2009

2. Relax
Saturday, 21 March 2009

3. Who’s Talking?
• J Chris Anderson / jchris@apache.org / @jchris
• Jan Lehnardt / jan@apache.org / @janl
• “Open Source Dudes”
• Directors, couch.io
Saturday, 21 March 2009

4. Who Are You?
Hi Last.fm!
Saturday, 21 March 2009

5. Damien Katz
Wassat?
Saturday, 21 March 2009
What’s CouchDB?

6. Schema Free (JSON)
•
Features
• Document Oriented,
Not Relational
• Highly Concurrent
• RESTful HTTP API
• JavaScript Powered
Map/Reduce
• N-Master Replication
• Robust Storage
Saturday, 21 March 2009

7. Schema Free (JSON)
•
Features
• Document Oriented,
Not Relational
• Highly Concurrent
• RESTful HTTP API
• JavaScript Powered
Map/Reduce
• N-Master Replication
• Robust Storage
Saturday, 21 March 2009

8. Schema Free ( JSON)
{
"_id": "BCCD12CBB",
"_rev": "1-AB764C",
"type": "person",
"name": "Darth Vader",
"age": 63,
"headware":
["Helmet", "Sombrero"],
"dark_side": true
}
Saturday, 21 March 2009

9. Schema Free ( JSON)
{
"_id": "BCCD12CBB",
"_rev": "2-AB764C",
"type": "person",
"name": "Darth Vader",
"age": 63,
"headware":
["Helmet", "Sombrero"],
"dark_side": true
}
Saturday, 21 March 2009

10. Schema Free ( JSON)
{
"_id": "BCCD12CBB",
"_rev": "3-AB764C",
"type": "person",
"name": "Darth Vader",
"age": 63,
"headware":
["Helmet", "Sombrero"],
"dark_side": true
}
Saturday, 21 March 2009
Access Tokens for MVCC

11. Schema Free ( JSON)
{
"_id": "BCCD12CBB",
"_rev": "3-AB764C",
"type": "person",
"name": "Darth Vader",
"age": 63,
"headware":
["Helmet", "Sombrero"],
"dark_side": true
}
Saturday, 21 March 2009
Access Tokens for MVCC

12. Schema Free (JSON)
•
Features
• Document Oriented,
Not Relational
• Highly Concurrent
• RESTful HTTP API
• JavaScript Powered
Map/Reduce
• N-Master Replication
• Robust Storage
Saturday, 21 March 2009

13. Document Oriented
Not Relational
• Documents in the Real World™
• Bills, letters, tax forms…
• Same type != same structure
• Can be out of date (so what?)
• No references
Saturday, 21 March 2009

14. Document Oriented
Not Relational
• Documents in the Real World™
Bills, letters, tax forms…
Natural Data
•
• Same type != same structure
•
Behaviour
Can be out of date (so what?)
• No references
Saturday, 21 March 2009

15. Document Oriented
Not Relational
couch = CouchRest.database!("http://
127.0.0.1:5984/tweets")
tweets_url = "http://twitter.com/
statuses/user_timeline.json"
tweets = http.get(tweets_url)
couch.bulk_save(tweets)
Saturday, 21 March 2009

16. Schema Free (JSON)
•
Features
• Document Oriented,
Not Relational
• Highly Concurrent
• RESTful HTTP API
• JavaScript Powered
Map/Reduce
• N-Master Replication
• Robust Storage
Saturday, 21 March 2009

17. Highly Concurrent
Number Bragging
Saturday, 21 March 2009

18. Highly Concurrent
Number Bragging
• Silly read-only benchmark with memory
saturation
Saturday, 21 March 2009

19. Highly Concurrent
Number Bragging
• Silly read-only benchmark with memory
saturation
• 2,500 req/s sustained on a 2Ghz dual
core 64-bit Athlon
Saturday, 21 March 2009

20. Highly Concurrent
Number Bragging
• Silly read-only benchmark with memory
saturation
• 2,500 req/s sustained on a 2Ghz dual
core 64-bit Athlon
• Using 9.8 MB RAM
Saturday, 21 March 2009

21. Highly Concurrent
Erlang Praising
Saturday, 21 March 2009

22. Highly Concurrent
Erlang Praising
• Erlang is worth its own talk
Saturday, 21 March 2009

23. Highly Concurrent
Erlang Praising
• Erlang is worth its own talk
• Executive Summary
Saturday, 21 March 2009

24. Highly Concurrent
Erlang Praising
• Erlang is worth its own talk
• Executive Summary
It’s fucking
awesome!
Saturday, 21 March 2009

25. Schema Free (JSON)
•
Features
• Document Oriented,
Not Relational
• Highly Concurrent
• RESTful HTTP API
• JavaScript Powered
Map/Reduce
• N-Master Replication
• Robust Storage
Saturday, 21 March 2009

26. ful  
CRUD
• Create
HTTP PUT /db/mydocid
• Read
HTTP GET /db/mydocid
• Update
HTTP PUT /db/mydocid
• Delete
HTTP DELETE /db/mydocid
Saturday, 21 March 2009

27. Schema Free (JSON)
•
Features
• Document Oriented,
Not Relational
• Highly Concurrent
• RESTful HTTP API
• JavaScript Powered
Map/Reduce
• N-Master Replication
• Robust Storage
Saturday, 21 March 2009

28. JavaScript powered
Map/Reduce
• Map functions extract data from your
documents
• Reduce functions aggregate intermediate
values *yawn*.
• The kicker: Incremental b-tree storage.
Saturday, 21 March 2009

29. Map Reduce Views
Docs Map
{ “user” : “Chris”, { “key” : “Alice”, “value” : 5 }
“points” : 3 } function(doc) { { “key” : “Bob”, “value” : 7 }
{ “user” : “Joe”, if (doc.user && doc.points) { { “key” : “Chris”, “value” : 3 }
“points” : 10 } emit(doc.user, doc.points);
{ “key” : “Joe”, “value” : 10 }
}
{ “user” : “Alice”, } { “key” : “Mary”, “value” : 9 }
“points” : 5 }
{ “user” : “Mary”,
“points” : 9 } Reduce
{ “user” : “Bob”,
“points” : 7 } function(keys, values, rereduce) { Alice ... Chris: 15
return sum(values);
} Everyone: 34
Saturday, 21 March 2009
• Parallel processing abstraction . Designed to run across many clusters.
• Iterate over documents emitting key/value pairs. Queries can be run to fetch key ranges.
• Incremental. Subsequent queries are fast.

30. Schema Free (JSON)
•
Features
• Document Oriented,
Not Relational
• Highly Concurrent
• RESTful HTTP API
• JavaScript Powered
Map/Reduce
• N-Master Replication
• Robust Storage
Saturday, 21 March 2009

31. Saturday, 21 March 2009

32. Saturday, 21 March 2009

33. Saturday, 21 March 2009

34. Saturday, 21 March 2009

35. Saturday, 21 March 2009

36. Saturday, 21 March 2009

37. Saturday, 21 March 2009

38. Saturday, 21 March 2009
periodic, notifier system

39. Saturday, 21 March 2009

40. Saturday, 21 March 2009
P2P apps

41. Render JSON Docs as HTML
shows/post.js /drl/_show/sofa/post/Hello-World-For-Real-This-Time
Saturday, 21 March 2009
• Side Effect Free JavaScript Function
• Converts from a single document into a response with any Content-Type
• CouchApp makes it easy to use http://embeddedjs.com templates in your _show functions.
• Cacheable with Etags

42. Render Views as HTML
lists/index.js /drl/_list/sofa/index/recent-posts?descending=true&limit=8
Saturday, 21 March 2009
• Side effect free and cacheable, like _show
• Run with different parameters for the head, tail, and each individual row of the view.

43. Schema Free (JSON)
•
Features
• Document Oriented,
Not Relational
• Highly Concurrent
• RESTful HTTP API
• JavaScript Powered
Map/Reduce
• N-Master Replication
• Robust Storage
Saturday, 21 March 2009

44. Robust Storage
Append Only
Resilient
Replication
Full fsync()
Saturday, 21 March 2009

45. Resources
• Twitter: @CouchDB & http://couchdb.org/
• Dress like a Couch:
http://shop.couchdb.com
• http://planet.couchdb.org/
• http://blog.racklabs.com/?p=74
• https://peepcode.com/products/couchdb-
with-rails
Saturday, 21 March 2009

46. couch.io
Berlin – London – Portland
If you need professional CouchDB
support talk to the dimwit(s) on stage
Saturday, 21 March 2009

47. anks!
Saturday, 21 March 2009

48. Saturday, 21 March 2009