These last couple of weeks I’ve learned about two new key-value stores:

Espresso: a new K-V store from LinkedIn

I’ve seen this new key-value store mentioned in Sid Anand’s slides presented at QCon. There’re no details about it, but soon I’ll start to ask around about it.

HyperDex: a searchable distributed key-value store

HyperDex:

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 pro- vides 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 multidimen- sional 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 provide strong consistency guarantees while supporting replication. An evaluation of the full system shows that HyperDex is orders of magnitude faster than Cassandra and MongoDB for finding partially specified objects. Additionally, HyperDex achieves high perfor- mance for simple get/put operations compared to current state-of-the-art key-value stores, with stronger fault-tolerance and comparable scalability properties.

At first glance it sounds interesting, but being only at version 0.2b8 and going after MongoDB and Cassandra in benchmarks doesn’t look good to me. Anyways I’m just starting to read about it. You can find and download the HyperDex paper after the break.