datomic-q-explain 
A Clojure library to explain the consumption of datoms during query
evaluation. It provides a drop-in replacement for
Datomic's q function called q-explain,
which returns an explanation of the query, rather than the original
query result. The explanation is a breakdown of the number of datoms
consumed by each :where clause and the index these datoms were drawn
from.
Some examples using the Datomic mbrainz example database and the sample queries are available in mbrainz.clj in the examples folder.
This library is still in early development; see the list of outstanding TODOs for current limitations and future plans.
License
Copyright © 2014 Pellucid Analytics
Distributed under the Eclipse Public License either version 1.0 or (at your option) any later version.