8. A system comprising one or more computers and one or more storage devices storing instructions that, when executed by the one or more computers, cause the one or more computers to perform operations comprising: receiving a transaction representing an update to a master graph database, the transaction including a new primitive and a first unique identifier for the new primitive in the master graph database; updating a concentric graph database with the new primitive, wherein the concentric graph database includes a first plurality of primitives and a second plurality of primitives, wherein each of the first plurality of primitives is also included in the master graph database and none of the second plurality of primitives are included in the master graph database, and wherein updating the concentric graph database with the new primitive comprises assigning a different, second unique identifier to the new primitive in the concentric graph database; and storing a mapping from the second unique identifier to the first unique identifier in the concentric graph database.
8. A system comprising one or more computers and one or more storage devices storing instructions that, when executed by the one or more computers, cause the one or more computers to perform operations comprising: receiving a transaction representing an update to a master graph database, the transaction including a new primitive and a first unique identifier for the new primitive in the master graph database; updating a concentric graph database with the new primitive, wherein the concentric graph database includes a first plurality of primitives and a second plurality of primitives, wherein each of the first plurality of primitives is also included in the master graph database and none of the second plurality of primitives are included in the master graph database, and wherein updating the concentric graph database with the new primitive comprises assigning a different, second unique identifier to the new primitive in the concentric graph database; and storing a mapping from the second unique identifier to the first unique identifier in the concentric graph database. 9. The system of claim 8 , the operations further comprising: monitoring a replica stream, wherein, for each primitive added to the master graph database, the master graph database publishes a transaction over the replica stream, the transaction including the primitive added to the master graph database.