Datalevin
An embeddable, ACID-compliant Datalog database built on a fork of LMDB, offering Datomic-style queries with a cost-based query optimizer and full-text and graph-style search.
Datalevin is a durable Datalog database meant to be simple, fast and versatile. It supports the Datomic flavor of the Datalog query language but, unlike Datomic, drops the temporal history features so that deleted data is simply gone, and it follows conventional ACID semantics rather than introducing unusual ones.
The database includes a novel cost-based query optimizer whose plans it reports as faster in its own comparisons against PostgreSQL and SQLite, and it can also be compared against graph databases such as Neo4j for read-heavy graph workloads. It provides ACID transactions on top of its own fork of LMDB, with write-ahead logging and asynchronous transactions for write-heavy workloads, and it can store large documents alongside full-text and vector search.
Datalevin is written in Clojure and released under the EPL-2.0 license.