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.
