Limitations

• Single writer. See also transaction.

• Attributes must be keywords.

• Attribute names have a length limitation: an attribute name cannot be more than 511 bytes long, due to LMDB key size limit.

• Because keys are compared bitwise, for range queries to work as expected on an attribute, its :db/valueType should be specified.

• nil cannot be stored. Floating point NaN cannot be stored.

• Big integers do not go beyond the range of [-2^1015, 2^1015-1], the unscaled value of big decimal has the same limit.

• The maximum individual value size is 2GB. Limited by the maximum size of off-heap byte buffer that can be allocated in JVM.

• The total data size of a Datalevin database has the same limit as LMDB's, e.g. 128TB on a modern 64-bit machine that implements 48-bit address spaces.

• Currently supports Clojure on JVM 11 or above, but adding support for other Clojure-hosting runtimes is possible, since bindings for LMDB exist in almost all major languages and are available on most platforms.