From the website:
ElephantDB is a database that specializes in exporting key/value data from Hadoop. ElephantDB is composed of two components. The first is a library that is used in MapReduce jobs for creating an indexed key/value dataset that is stored on a distributed filesystem. The second component is a daemon that can download a subset of a dataset and serve it in a read-only, random-access fashion. A group of machines working together to serve a full dataset is called a ring.
Since ElephantDB server doesn’t support random writes, it is almost laughingly simple. Once the server loads up its subset of the data, it does very little. This leads to ElephantDB being rock-solid in production, since there’s almost no moving parts.
ElephantDB server has a Thrift interface, so any language can make reads from it. The database itself is implemented in Clojure.
I rather like that, “…almost no moving parts.”
That has to pay real dividends over the id shuffle in some topic map implementations. Both in terms of processing overhead as well as in auditing.