When using database replication, you may occasionally encounter synchronization conflicts or synchronization errors. Synchronization conflicts occur when the same record is updated in two members of the replica set, and Microsoft Jet attempts to synchronize the two versions. The synchronization succeeds, but the changes from only one of the members are applied to the other. Synchronization errors occur when a data change in one replica set member cannot be applied to another member because it would violate a constraint such as a referential integrity rule or uniqueness assertion. The synchronization succeeds, but the content of the database in different members starts to diverge.
Synchronization errors and design errors are much more significant problems than synchronization conflicts because the replica set members no longer share a common design or identical data. This section describes the factors contributing to conflicts and errors, and suggests ways to prevent or resolve them.