Couch Db

Next Generation Data Storage with CouchDb Jan Lehnardt <jan@php.net> 1

About Me • Freelancing Developer with strong focus on the Web for ~6 Years • Studies in Computer Science and Linguistics (not yet ﬁnished :-) • Co-founder of FREISATZ • Love Rock music and kittens 2

About You? •What do you work on? • What are you interested in? • Why are you here? 3

Target Audience • (Let’s see how well this matches the responses to the last slide) • Webdevelopers, interested in new technology • System Architects that look for scalable and fault tolerant software solutions • Anybody else is welcome, too 4

Forget SQL • Just for a moment, imagine you know nothing about relational data, normalization and other fancy terminology • You only want to store data 5

The Four Pillars of Data Management 6

Four Pillars (1): Save • Save data securely, permanent etc... • i.e. ACID compliant • Save data efﬁcient 7

Four Pillars (II): See • Make data available for easy retrieval • Integrate simple reporting methods • Provide (fulltext) search 8

Four Pillars (III): Secure • Enable strong compartmentalization of data • Assign users, groups and roles to data • Allow connections over SSL 9

Four Pillars (IV): Share • To make it complete: • Do all that in a distributed way • On- and Ofﬂine(!) 10

No Relations • Enter CouchDb • New implementation, no legacy • Designed to… • …implement the four Pillars • …leverage recent paradigm shifts 11

CouchDb for Database Experts Now, remember SQL and all you know about traditional database systems 12

Databases Pool for related data 13

Documents • Records of data • Individual storage elements • Can have an arbitrary (JSON) structure… • …but don’t have to! • Attachments • Have IDs & revisions 14

Views • Similar to Views • Compiled, pre-deﬁned subset of stored data • External JavaScript Daemon(s) 15

CouchDb Features Roubust Data Storage Repliaction REST API User Authentication JavaScript Views Built on Erlang/OTP Your Feature Here, it’s Fulltext Search Open Source! 16

Documents • Individual storage elements • Can have an arbitrary (JSON) structure… • …but don’t have to! • Attachments • Have IDs & revisions 17

Example Document { _id:”098F6BCD4621D373CADE4E832627B4F6”, _rev: 4134847, “BugId”: “098F6BCD4621D373CADE4E832627B4F6”, “Counter”:1, “Name”:”test”, “Type”:”Project” } 18

Data Storage • State-of-the-art storage model • MVCC with optimistic locking • Sacles magnitudes better than pessimistic locking • Append-only writes 19

REST API • Easy retrieval using a method proven to be scalable: HTTP • Exchange in industry-standard formats (JSON) • Simple and intuitive interface 20

Example URIs • http://server/company/_all_docs • http://server/company/765432 • http://server/company/_design/people • http://server/company/_design/people? count=7&startkey=”L”&endkey=”M” 21

JavaScript Views • JS Functions to perform pattern matching on documents • Map-Reduce to deﬁne document subsets • (Actual language changeable) 22

Example View function(doc) { map(doc.time, { 'teaser':doc.text.substr(0,10), '_id':doc.id }); } 23

Example View function(doc) { if(“Article” == doc.type) { map(doc.time, { 'teaser':doc.text.substr(0,10), '_id':doc.id }); }} 24

Fulltext Search • Leverages Lucene • Reference implementation included • Simple API to plug in other search technology 25

Security and Authentication • Not yet implemented • Will have • Standard user authentication for applications • Document ownership 26

Replication • Bi-directional replication (or synchronization) between any number of instances. • Online, and: • Ofﬂine(!) • Including consistent conﬂict resolution for disconnected systems. Wow! 27

Erlang Core • Awkward syntax, but hey :-) • Multi-everything • Lightweight threading • Awesome performance • Die-on-error design 28

Demo 29

Cool things to do with CouchDb • Distributed Anything-Application • The Wiki • Version Control System • FUSE plugin • MySQL Storage Engine 30

About Damien • Damien Katz • Ex-Iris/Lotus/IBM • Helped creating the Lotus Notes Database / Domino 31

Links • http://couchdb.com/ • http://couchdbwiki.com/ • http://damienkatz.net/ • http://jan.prima.de/ • The Book 32

Cheers! You’ve been great! 33

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Couch Db

by Ross Lawley on Nov 15, 2007

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Couch Db — Presentation Transcript