Scalaris: Scalable Web Applications with a Transactional Key-Value Store
Modern web applications are commonly built on top of key-value stores for seamless horizontal scalability, e.g. in Cloud environments. In contrast to relational databases most key-value stores support only eventually consistency and a restricted data model (single index). Scalaris  is a scalable, transactional, distributed key-value store. It thus overcomes the consistency and data model restrictions of common key-value stores. Atomically updating a set of key-value pairs allows to map relational data models and multiple indices to the NoSQL paradigm. After a short introduction to Scalaris and the Wiki data model, we show how to map a Wiki (including backlinks, category pages, etc) to key-value pairs and how to use Scalaris as a storage backend. Several approaches to optimise such mappings with regard to scalability and performance will be presented and evaluated.  https://code.google.com/p/scalaris/
Watch the video of Nico Kruber's talk here.