Replication Server depends on data servers to provide transaction-processing services. To guarantee the integrity of distributed data, data servers must comply with transaction-processing conventions, such as atomicity and consistency.
Data servers that store primary data provide most of the concurrency control needed for the distributed database system. If a transaction fails to update a table with primary data, Replication Server does not distribute the transaction to other sites. When a transaction does update primary data, Replication Server distributes the changes and, unless a failure occurs, the update succeeds at all sites that have subscribed to the data.