Sybase Replication Agent consists of a set of components that work together to perform all the operations required to propagate transactions from a primary database for replication.
The main Replication Agent components and their functions are:
Log Reader – reads the transaction log in the primary database to retrieve transactions for replication.
Log Transfer Interface (LTI) – generates Log Transfer Language (LTL) and sends it to the primary Replication Server.
Log Administrator – administers the Replication Agent transaction log and manages transaction log objects.
Log Transfer Manager (LTM) – manages all the other components and coordinates their operations and interactions.
Figure 1-4 illustrates the flow of data through a Replication Agent during replication.
Figure 1-4: Replication Agent operational data flow
The Log Reader component retrieves transaction data from the transaction log in the primary database, generates change set data, and passes the change sets to the LTI. The LTI component processes the change set data from the Log Reader and generates the LTL to send to the primary Replication Server. The LTI component also receives messages from the primary Replication Server.
Although the LTM component is not involved in the flow of data from the primary database to the primary Replication Server, it coordinates the activities of the other Replication Agent components and processes any errors generated by those components.
Sybase Replication Agent provides an administrative user interface through its administration port.
The administration port allows an Open Client application to log in to a Replication Agent instance, as if the Replication Agent were an Open Server application. Once logged in, the administrative client can issue commands to control, administer, and monitor the Replication Agent instance.
The administration port communicates with the client through the Sybase JDBC driver (jConnect for JDBC).
Figure 1-5 illustrates the flow of command and control messages among Replication Agent components.
Figure 1-5: Replication Agent command processing
The administration port passes commands from the administrative client to the Replication Agent components. The administration port also processes the messages from Replication Agent components, and passes those messages out to the client.
Sybase Replication Agent version 12.5 requires a Java Runtime Environment (JRE) on the computer that will act as the Replication Agent host machine.
For more information on installing and setting up a JRE, see:
Sybase Replication Agent Installation Guide
The release bulletin for Sybase Replication Agent version 12.5
