A method replicates data between instances of a distributed database. The method identifies at least two instances of the database at distinct geographic locations. The method tracks changes to the database by storing deltas. Each delta has a row identifier that identifies the piece of data modified, a sequence identifier that specifies the order in which the deltas are applied to the data, and an instance identifier that specifies where the delta was created. The method determines which deltas to send using an egress map that specifies which combinations of row identifier and sequence identifier have been acknowledged as received at other instances. The method builds a transmission matrix that identifies deltas that have not yet been acknowledged as received. The method then transmits deltas identified in the transmission matrix. After receiving acknowledgement that transmitted deltas have been incorporated into databases at other instances, the method updates the egress map.