Replication

TimesTen Classic replication enables you to achieve near-continuous availability or workload distribution by sending updates between two or more hosts.

A master host is configured to send updates and a subscriber host is configured to receive them. A host can be both a master and a subscriber in a bidirectional replication scheme. Time-based conflict detection and resolution are used to establish precedence in case the same data is updated in multiple locations at the same time.

TimesTen recommends the active standby pair replication scheme configuration for highest availability. It is the only replication configuration that you can use for replicating cache groups. An active standby pair includes an active database, a standby database, and optional read-only subscriber databases.

When replication is configured, a replication agent is started for each database. Each replication agent can send updates to one or more subscribers and to receive updates from one or more masters. Each of these connections is implemented as a separate thread running inside the replication agent process. Replication agents communicate through TCP/IP stream sockets.

For maximum performance, the replication agent detects updates to a database by monitoring the existing transaction log. It sends updates to the subscribers in batches, if possible. Only committed transactions are replicated. On the subscriber host, the replication agent updates the database through an efficient internal interface that avoids the overhead of the SQL layer.

See Data Replication Within TimesTen Classic for more information about replication configurations.