There are many datastores written in Erlang, for example Riak, Dynomite, CouchDb, Scalaris, have I missed any?
I know that Java and C/C++ have also been used to write datastores (Cassandra, Hypertable, etc), but have any Datastores been written in any other functional languages such as F#, Scala, Haskell, Clojure, etc? The reason I am asking this (and many other functional programming and Erlang type questions) is to assess the feasibility of functional programming languages for real world projects.
As a side note it has been pointed out to me that I mean the actual implementation language of the datastore itself, and not the client language to access the datastore (ie: via ODBC).