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CouchDB Talk JChris NYC

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Chris Anderson
Chris Anderson

This document provides an introduction and overview of CouchDB including: - Background on the creators and history of CouchDB's development - An explanation of how CouchDB differs from traditional SQL databases through its use of RESTful HTTP, schemaless JSON documents, map/reduce views, and incremental replication - A description of CouchDB's internal architecture and key modules - An invitation for readers to get involved with the CouchDB community

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CouchDB Talk JChris NYC
Hello • Chris Anderson <jchris@apache.org> • Blog: http://jchris.mfdz.com • Founder, Grabb.it (web analytics for music) • Ruby on Rails veteran • CouchDB committer
And You? • Used CouchDB (for fun) • Evaluating or using it (for a project) • Interested in contributing? • Just here for the pizza?
History • Damien Katz <http://damienkatz.net/> • Worked on Lotus Notes & MySQL • Started in 2005: C++ and XML, on Windows • 2006: Moved to Erlang, JSON, and POSIX • 0.7.0 first release of today’s CouchDB • Version 1.0 Planned for the end of 2008
Why CouchDB? • Common use cases no longer fit RDBMS • Native to web applications • Peer-based replication for freedom • Takes today’s scalability lessons to heart
This Talk • How is CouchDB different (from RDBMS)? • Example HTML/Javascript application • Quick tour of the internals
How Is CouchDB Different? RESTful HTTP Schemaless JSON Documents Map/Reduce Views Incremental Replication
How Is CouchDB Different? (from SQL RDBMS) RESTful HTTP Binary Protocol Schemaless JSON Documents Typed Columns & Primary Keys Map/Reduce Views Ad-hoc Queries Incremental Replication Replication Logs
RESTful HTTP Built for the web Javascript Test Suite Standard HTTP Clients, Proxies, Load Balancers & Caches
RESTful HTTP Built for the web Enterprisey Javascript Test Suite Battle Hardened Standard HTTP Clients, Proxies, Load Balancers & Caches Protocol Specific Tools
Schemaless JSON Documents Flat Namespace Arbitrary JSON Structures Identified By URIs Optimistic Locking (ACID/MVCC)
Schemaless JSON Documents Flat Namespace Tables Arbitrary JSON Structures Typed Columns and Key Constraints Identified By URIs Primary Keys Optimistic Locking (ACID/MVCC) Row or Column Level Locking
Map/Reduce Views Functional Javascript Incremental Updates Predefined High-Performance Reads
Map/Reduce Views Functional Javascript SQL Statements Incremental Updates Independent Predefined Ad-hoc and Complex High-Performance Reads Indexes Computed on Writes
Incremental Replication User Triggered Offline Clients Resilient & Restartable HTTP
Incremental Replication User Triggered Continuous Offline Clients Master/Slave Resilient & Restartable Critical Path HTTP Log Based
CouchDB A new way to write web applications. HTML / Javascript _design Documents p2p Replication
Live Code! http://169.254.251.59:5984/_utils/
CouchDB Internals • couch_httpd.erl • Request Dispatch • Create Database • Get Document • Other Modules
Request Dispatch
Create Database
Get Document
Other Modules • couch_btree.erl • The heart of the storage module (stores Erlang terms sorted by key using user specified sort funtions) • couch_db_updater.erl • Translates document requests into Btree actions. • couch_query_servers.erl • Communicates with the external (Javascript etc) view servers.
Join Us • #couchdb on irc.freenode.net • http://couchdb.org • mailing lists • links to wiki and subversion checkout
Thank You! Any Questions?

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CouchDB Talk JChris NYC

  • 2. Hello • Chris Anderson <jchris@apache.org> • Blog: http://jchris.mfdz.com • Founder, Grabb.it (web analytics for music) • Ruby on Rails veteran • CouchDB committer
  • 3. And You? • Used CouchDB (for fun) • Evaluating or using it (for a project) • Interested in contributing? • Just here for the pizza?
  • 4. History • Damien Katz <http://damienkatz.net/> • Worked on Lotus Notes & MySQL • Started in 2005: C++ and XML, on Windows • 2006: Moved to Erlang, JSON, and POSIX • 0.7.0 first release of today’s CouchDB • Version 1.0 Planned for the end of 2008
  • 5. Why CouchDB? • Common use cases no longer fit RDBMS • Native to web applications • Peer-based replication for freedom • Takes today’s scalability lessons to heart
  • 6. This Talk • How is CouchDB different (from RDBMS)? • Example HTML/Javascript application • Quick tour of the internals
  • 7. How Is CouchDB Different? RESTful HTTP Schemaless JSON Documents Map/Reduce Views Incremental Replication
  • 8. How Is CouchDB Different? (from SQL RDBMS) RESTful HTTP Binary Protocol Schemaless JSON Documents Typed Columns & Primary Keys Map/Reduce Views Ad-hoc Queries Incremental Replication Replication Logs
  • 9. RESTful HTTP Built for the web Javascript Test Suite Standard HTTP Clients, Proxies, Load Balancers & Caches
  • 10. RESTful HTTP Built for the web Enterprisey Javascript Test Suite Battle Hardened Standard HTTP Clients, Proxies, Load Balancers & Caches Protocol Specific Tools
  • 11. Schemaless JSON Documents Flat Namespace Arbitrary JSON Structures Identified By URIs Optimistic Locking (ACID/MVCC)
  • 12. Schemaless JSON Documents Flat Namespace Tables Arbitrary JSON Structures Typed Columns and Key Constraints Identified By URIs Primary Keys Optimistic Locking (ACID/MVCC) Row or Column Level Locking
  • 13. Map/Reduce Views Functional Javascript Incremental Updates Predefined High-Performance Reads
  • 14. Map/Reduce Views Functional Javascript SQL Statements Incremental Updates Independent Predefined Ad-hoc and Complex High-Performance Reads Indexes Computed on Writes
  • 15. Incremental Replication User Triggered Offline Clients Resilient & Restartable HTTP
  • 16. Incremental Replication User Triggered Continuous Offline Clients Master/Slave Resilient & Restartable Critical Path HTTP Log Based
  • 17. CouchDB A new way to write web applications. HTML / Javascript _design Documents p2p Replication
  • 19. CouchDB Internals • couch_httpd.erl • Request Dispatch • Create Database • Get Document • Other Modules
  • 23. Other Modules • couch_btree.erl • The heart of the storage module (stores Erlang terms sorted by key using user specified sort funtions) • couch_db_updater.erl • Translates document requests into Btree actions. • couch_query_servers.erl • Communicates with the external (Javascript etc) view servers.
  • 24. Join Us • #couchdb on irc.freenode.net • http://couchdb.org • mailing lists • links to wiki and subversion checkout
  • 25. Thank You! Any Questions?