Introducing SQL Anywhere Studio
Replication Technologies
Propagation methods
Some replication technologies rely on the presence of a continuous, or at least almost continuous, connection between the databases. Through this connection, the two databases conduct an ongoing dialogue. These types of systems excel at replicating changes quickly. Indeed, given sufficient resources and channel capacity, replication can occur reliably with a lag time of no more than a few seconds.
Replication server is a near real-time replication system designed primarily for replication between a small number of databases. It is normally used with a continuous, reliable, high-speed connection. It incorporates store-and-forward techniques that allow replication to continue automatically when a connection is lost and later re-established.
The main drawback of this type of system is that a reliable, continuous connection can be expensive to maintain. This restriction makes connection-based technologies suited to replication between two large, fixed databases. In environments where the remote machines are mobile or are only occasionally connected, message-based or session-based technologies provide more flexible solutions.