This is a very, very big topic. For the most part, the issues are covered in the various SQL versus NoSQL debates all over the Internet. For example:
* Cassandra and its NoSQL siblings have no concept of an in-database "join" * Cassandra and its NoSQL siblings do not allow you to update multiple "tables" in a single transactions * Cassandra's API is specific to it, and not portable to any other data store * Cassandra currently has simplistic facilities to deal with various kinds of conflicting write. * Cassandra is strongly optimized for multiple machine distributions, whereas relational databases tend to be optimized for a single powerful machine. * Cassandra and its siblings are weak at ad hoc queries on tables that you did not think to index in advance On Mon, May 10, 2010 at 11:06 AM, Peter Hsu <pe...@motivecast.com> wrote: > I've seen a lot of threads and posts about why Cassandra is great. I'm > fairly sold on the features, and the few big deployments on Cassandra give it > a lot of credibility. > > However, I don't believe in magic bullets, so I really want to understand the > potential downsides of Cassandra. Right now, I don't really have a clue as > to what Cassandra is bad at. I took a look at > http://wiki.apache.org/cassandra/CassandraLimitations which is helpful, but > doesn't characterize its weaknesses in ways that I can really comprehend > until I've actually used Cassandra and understand some of the internals. It > seems that the community would benefit from being able to answer some of > these questions in terms of real world use cases. > > My main questions: > * Are there designs in which a SQL database out-performs or out-scales > Cassandra? > * Is there a pros vs cons page of Cassandra against an open source SQL > database (MySQL or Postgres)? > > I do plan on attending the training session next Friday in Palo Alto, but > it'd be great if I had some more food for thought before I attend. > >
