US Patent 8108343 De-duplication and completeness in multi-log based replication

Aspects of the subject matter described herein relate to multi-log based replication. In aspects, database fragments are associated with different logs. Each change to a duplicated database record may be recorded in multiple logs. A history data structure is used to determine when duplication schemas are valid. A duplication schema indicates what database fragments duplicate one or more database records. For a particular time range, the duplication schema history is used to determine whether currently available logs include all changes. If multiple logs include the same change, one log may be selected to provide the change. Non-duplicative changes may be placed into a single data stream usable to update a remote database.