HyperDex

Abstract

Distributed key-value stores are now a standard component of high-performance web services and cloud computing applications. While key-value stores offer significant performance and scalability advantages compared to traditional databases, they achieve these properties through a restricted API that limits object retrieval-an object can only be retrieved by the (primary and only) key under which it was inserted. This paper presents HyperDex, a novel distributed key-value store that provides a unique search primitive that enables queries on secondary attributes. The key insight behind HyperDex is the concept of hyperspace hashing in which objects with multiple attributes are mapped into a multidimensional hyperspace. This mapping leads to efficient implementations not only for retrieval by primary key, but also for partially-specified secondary attribute searches and range queries. A novel chaining protocol enables the system to achieve strong consistency, maintain availability and guarantee fault tolerance. An evaluation of the full system shows that HyperDex is 12-13× faster than Cassandra and MongoDB for finding partially specified objects. Additionally, HyperDex achieves 2-4× higher throughput for get/put operations.

HyperDex

“…Surprisingly, the open-source release of the HyperDex system [20] uncovered various misunderstandings surrounding the CAP Theorem [22]. The popular CAP refrain ("C, A, P: pick any two") causes the subtleties in the definitions of C, A and P to be lost, even on otherwise savvy developers.…”