I'm currently evaluating possible NoSQL WideTable systems for use as a storage backend for an experimental project I'm working on but I'm struggling with the fact that many of these seem to have vague/incomplete documentation and it's hard to determine whether a specific feature is supported.
Specifically I need to be able to do queries which return rows which have certain values for a specific Column and this needs to be doable without relying on a complete row scan (which afaict means Cassandra is out as an option).
What systems are there that have this feature? Sytems with a RESTful HTTP API or a .Net Client/Driver library are also preferable.