Some Replication Agents cannot access the native transaction log of a primary database to acquire the information necessary to replicate transactions.
When a native transaction log cannot be used, the Replication Agent uses its own proprietary transaction log to capture and record transactions in the primary database for replication. Such a Replication Agent generates SQL scripts that run in the primary database to create the Replication Agent transaction log.
Native transaction logs are used by the RepAgent thread (for Adaptive Server), Replication Agent for DB2, and Replication Agent for DB2 Universal Database on UNIX and Windows platforms.Sybase Replication Agent (for Microsoft SQL Server and Oracle) uses a transaction log that it creates and maintains in the primary database. The Sybase Replication Agent transaction log consists of database objects (triggers, tables, and procedures) in the primary database.
See the Replication Agent Administration Guide Volume 1.