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I tried to explain to the reporter why Cassandra's data model (particularly that it supports an arbitrary number of columns per row) makes it support denormaliz
by jbellis 17y ago
I tried to explain to the reporter why Cassandra's data model (particularly that it supports an arbitrary number of columns per row) makes it support denormalization better than traditional rdbmses, and somehow that got turned into "cassandra supports an arbitrary number of rows."
This and a few other poor explanations make me wince reading this. So I don't particularly recommend this article, although I've seen worse. :)
TFA does at least link the original interview w/ Ryan King of Twitter (http://nosql.mypopescu.com/post/407159447/cassandra-twitter-an-interview-with-ryan-king http://nosql.mypopescu.com/post/407159447/cassandra-twitter-...) which is much better for people at HN level.
My own article at http://www.rackspacecloud.com/blog/2010/02/25/should-you-switch-to-nosql-too/ http://www.rackspacecloud.com/blog/2010/02/25/should-you-swi..., although high level, also has some useful links for those who want to drill down for more details.
- JulianMorrison 17y agoI wish Ryan King had said why the other DBs named were rejected. That could be useful info.
- socratees 17y agoSites similar to twitter are worried about Read/Writes and up time rather than concurrency and locking mechanisms. All flavors of NOSQL databases are best suited for this. Sites like amazon.com, or any transaction processing site can't think of using NOSQL. tl:dr; NOSQL is good until transaction processing & concurrency comes in to picture.
- andrewtj 17y agoScalaris (http://code.google.com/p/scalaris/ http://code.google.com/p/scalaris/) is consistent and has transactions. As an aside, three sentences doesn't really warrant a "tl;dr".
- z8000 17y agoNot being snarky here but how can anyone seriously consider Scalaris for any data that's even remotely important? http://code.google.com/p/scalaris/wiki/FAQ#Is_the_store_persisted_on_disk http://code.google.com/p/scalaris/wiki/FAQ#Is_the_store_pers...?
- andrewtj 17y agoIt certainly limits it from being useful if you don't have dollars to throw at high-end infrastructure, but it's not quite as terrible as it sounds. Effectively all it means is that you can't cold start it. How big a problem this is depends like anything else on the application in question.
- z8000 17y agoAs I write this comment I just know that in 5 years I will look at it and chuckle at myself but... it boggles my mind to consider a pure-RAM system that relies on at least one copy of the dataset being available forever in some system's "memory grid". http://highscalability.com/are-cloud-based-memory-architectures-next-big-thing http://highscalability.com/are-cloud-based-memory-architectu...
- rbranson 17y agoAmazon pioneered Dynamo, a NoSQL-style scalable distributed key-value store, for building many of their site's internal services upon. It's backed by BDB and can be tuned to guarantee disk writes across multiple nodes if needed. See the paper below. http://www.allthingsdistributed.com/2007/10/amazons_dynamo.html http://www.allthingsdistributed.com/2007/10/amazons_dynamo.h...
- JulianMorrison 17y agoMongoDB does implicit transactions around single queries/commands on single documents, that can be complex enough to be used to create always-recoverable or always-resumable protocols.
- jbellis 17y agoIt doesn't take a _whole_ lot of familiarity with the other systems to see which of his criteria they failed.
- larrywright 17y agoThis was actually previously discussed by Twitter's Evan Weaver. I can't find the article I'm thinking of, but this is close: http://blog.evanweaver.com/articles/2009/07/06/up-and-running-with-cassandra/ http://blog.evanweaver.com/articles/2009/07/06/up-and-runnin... My understanding is that it came down to Cassandra being the only one that was well tested in multi-datacenter configurations. I think there were other reasons, but that was the big one.