Datomic [0] uses SQUUIDs [1] (Semi sequential UUIDs) to work around this: Many UUID generators produce data that is particularly difficult to index, wh

Datomic [0] uses SQUUIDs [1] (Semi sequential UUIDs) to work around this: Many UUID generators produce data that is particularly difficult to index, which can cause performance issues creating indexes. To address this, Datomic includes a semi-sequential UUID generator, Peer.squuid. Squuids are valid UUIDs, but unlike purely random UUIDs, they include both a random component and a time component. [0] http://www.datomic.com/ http://www.datomic.com/ [1] http://docs.datomic.com/identity.html#sec-6 http://docs.datomic.com/identity.html#sec-6 edit: formatting