Adaptive Server Enterprise uses a text pointer to identify the location of text and image column data. The text pointer is passed to system functions that perform the actual updates to data in these large columns. The same technique is used internally in Replication Server to apply LOB datatypes. Replication Server obtains a text pointer, and data server function calls are made to apply the data to replicate databases.
When a non-Sybase database is the replicate database, the database gateway used to communicate with the replicate database must be able to emulate the Adaptive Server text pointer processing. The ECDA Option for ODBC, ECDA Option for Oracle, and the Mainframe Connect DirectConnect for z/OS Option gateways provide this feature.
The ECDA Option for ODBC provides support for LOB replication into Microsoft SQL Server databases. See Chapter 10, “Microsoft SQL Server Replicate Data Server Issues.”
In a replicate database in IBM DB2 UDB for z/OS, you can use the Mainframe Connect DirectConnect for z/OS option to provide a “gatewayless” connection to the replicate database, and use modified rs_get_textptr and rs_writetext function strings to support LOB replication into DB2. See Chapter 9, “DB2 UDB Replicate Data Server Issues for UNIX, Windows, and Linux.”
You might be able to remove the dependency on text pointers from the Replication Server (or the ECDA database gateway) by modifying the Replication Server text pointer function strings and creating a stored procedure in the replicate database.
