Merge replication

Merge replication is the process of distributing data from Publisher to Subscribers, allowing the Publisher and Subscribers to make updates independently, and then merging the updates between sites.

Merge replication allows various sites to work autonomously and at a later time merge updates into a single, uniform result. The initial snapshot is applied to Subscribers, and then Microsoft SQL Server tracks changes to published data at the Publisher and at the Subscribers. The data is synchronized between servers continuously, at a scheduled time, or on demand. Because updates are made on more than one server, the same data may have been updated by the Publisher or by more than one Subscriber. Therefore, conflicts can occur when updates are merged.

Merge replication includes default and custom choices for conflict resolution that you can define as you configure a merge publication. When a conflict occurs, a resolver is invoked by the Merge Agent and determines which data will be accepted and propagated to other sites.