LevelDB: A Fast Persistent Key-Value Store
News about LevelDB has been making the rounds lately. It's another Google project and it definitely looks interesting. LevelDB is a key-value store in library form. It does not appear to be a complete product in and of itself, but can be utilized by many other products.
One very interesting note is the fact the Basho is working on using LevelDB as one of the back end storage options for Riak! It looks like LevelDB would work well for those that are using the InnoDB back end currently. The Bitcast back end keeps all of it's keys in memory and thereby has some limitations as to how many values can be stored per node. InnoDB doesn't have this same limitation and neither does LevelDB.