Method and System for Efficiently Replicating Data in Non-Relational Databases

A method replicates data between instances of a distributed database. The method tracks changes to the distributed database at a first instance by storing deltas. Each delta includes a row identifier that identifies a row having a base value, and a sequence identifier that specifies an order in which the delta is applied to the base value to compute a current value for the row. The method identifies a set of deltas to send to a second instance based in part on an egress map at the first instance, wherein the egress map specifies which combinations of row identifier and sequence identifier have been acknowledged as received at the second instance. The method then transmits the identified set of deltas to the second instance. After receiving acknowledgement that the deltas in the identified set of deltas have been incorporated into the second instance, the egress map is updated accordingly.