How would a "NOSQL" database be designed for consumer apps (e.g. social bookmarking) [closed]

Question

I've been reading up on a lot of posts about non-relational databases, the whole NOSQL movement, and there's a lot of fresh new activity around it. It seems like a very interesting approach to building highly scalable web applications but unfortunately (but also a good thing at this nascent stage) there isn't quite a clear leader/standard at the moment.

My background is in the LAMP stack (with MySQL as the dB) and I wanted to understand what differences and limitations there would be - but with using the example of real life web applications out there. There's a ton of good articles about the theory of pros/cons of RDBMS vs non-RDBMS, but I haven't found anything that walks through an example of how an existing web app (for example social bookmarking) would be built different to take advantage of the new dB structure and what features one would have to leave out if any - where the NOSQL dB could be key-value or document-centric or graphs.

Would anyone be willing to take a stab at a high-level comparison of a NOSQL vs RDBMS model/architecture of a real-world web app (such as social bookmarking or any other example that might explain the concepts well)?

For reference to others, here are a few of the articles I have come across:

• Non-Relational Database Design
• http://nosql-databases.org/
• http://linux-mag.com/cache/7579/1.html
• http://blog.boxedice.com/2009/07/25/choosing-a-non-relational-database-why-we-migrated-from-mysql-to-mongodb/
• http://bret.appspot.com/entry/how-friendfeed-uses-mysql
• http://metabrew.com/article/anti-rdbms-a-list-of-distributed-key-value-stores/
• http://rackspacecloud.com/blog/2009/11/09/nosql-ecosystem/
• http://horicky.blogspot.com/2009/11/nosql-patterns.html

Haversine

Voted to close. This is a Q&A site, and you've asked for a set of essays. – Airsickness

Don't close this, I'd give 200 rep to hear an answer. I to have never actually found a working port of a web app to a NoSQL database, at least, one that would scale. – Hema

@Hema - any reason why you downvoted my answer? I'd like the opportunity to recitify... – Wynnie

@Wynnie I didn't down-vote your answer. I only downvote answers with invalid information (which is almost never). – Hema

@Hema - are you willing to add a +200 bounty like you said in your comment? – Delois

Answer 1

The main reason is scale (Facebook, MySpace)

Check out these articles:

Facebook's Cassandra - A Massive Distributed Store

MySpace Qizmt - MySpace's Mapreduce Framework

As you are already using Lucene, this may be of interest:

Katta - Lucene in the cloud

Wynnie