Sybase Replication Agent

Sybase Replication Agent is a replication system component that captures transactions in a DB2 Universal Database (on UNIX and Windows platforms), Microsoft SQL Server, or Oracle primary database, and then transfers those transactions to Replication Server.

The Sybase Replication Agent for DB2 Universal Database uses the native DB2 transaction log to acquire transaction data to be replicated.

The Sybase Replication Agent for Microsoft SQL Server and Oracle creates its own transaction log to record the transactions (or procedure invocations) to be replicated. The Log Reader component of Replication Agent reads the transaction log to retrieve the transaction from the primary database.

After transaction data is retrieved from the primary database, the Log Transfer Interface (LTI) component of Replication Agent processes the transaction and the resulting “change set” data and generates LTL output, which Replication Server uses to distribute the transaction to the subscribing replicate database(s).

Figure 5-3: Sybase Replication Agent data flow

Figure 5-3 illustrates Sybase Replication Agent data flow from the primary database to Replication Agent with processing by the three components within Replication Agent, which are Log Reader, Log Transfer Manager, and Log Transfer Interface. After processing by Replication Agent, L T L output is generated and sent to Replication Server.

Sybase Replication Agent uses information stored in the Replication Server System Database (RSSD) of the primary Replication Server to determine how to process the replicated transactions to generate the most efficient LTL.

After it receives LTL from Replication Agent, the primary Replication Server sends the replicated transaction to a replicate database, either directly or by way of a replicate Replication Server. The replicate Replication Server converts the replicated data to the native language of the replicate database, and then sends it to the replicate database server for processing. When the replicated transaction is processed successfully by the replicate database, the replicate database is synchronized with the primary database.

Sybase Replication Agent runs as a stand-alone application, independent of the primary database server, the primary Replication Server, and any other components of a replication system.

Sybase Replication Agent can reside on the same host machine as the primary database or any other component of the replication system, or it can reside on a separate machine from any other replication system components.