Like Ingres Replicator, Ingres Star maintains data across two or more distributed databases.

However, Ingres Star uses two-phase commit between the local and remote databases. During an update by a local user, Ingres Star takes locks on the local database and the remote databases, and does not release the locks until the two-phase commit procedure has been successfully completed. Holding locks can cause delays for the local user.

Unlike Ingres Star, Ingres Replicator updates the local database asynchronously, and takes locks on the Ingres Replicator queues and each remote database in turn for the duration of the two-phase commit procedure. Thus, using Ingres Replicator instead of Ingres Star results in significant performance gains.

With Ingres Replicator, you can customize your replication environment in ways that are not available with Ingres Star.

With Ingres Star, either the transaction is completed in all databases or in none of them. With Ingres Replicator, however, two users can update the same record in different replicated databases. This can result in a collision. For more information, see Collision Design on page 48.