Replication Server 15.5 includes enhancements for requesting changes to replication definitions that automatically coordinate the propagation of replication definition changes and data replication. You can request replication definition changes directly at the primary database using the alter replication definition, alter applied replication definition, or alter request function replication definition commands, while making changes to the database schema.
You can:
Issue a replication definition command directly from a primary database.
Use an alter replication definition command to instruct Replication Server to suspend the target DSIs after Replication Server applies all data for the old replication definition version at the target database. This provides a window for you to alter the target schema and alter customized function strings before the data for the new replication definition version arrives.
Verify that Replication Server can execute a replication definition request successfully by executing the request without changing any data.
Drop columns from a replication definition using alter replication definition.
Instruct Replication Server to skip a failed replication definition request sent by a Replication Agent. When a replication definition command fails at the primary Replication Server, Replication Agent shuts down. If you restart Replication Agent, the failed command executes again unless Replication Server skips the command.
These enhancements make coordinating database schema changes and replication definition changes more convenient because there is no downtime for the primary database, and minimal or no downtime for the replicate database. When you issue a replication definition change request, Replication Server determines if there is a need to create a new replication definition version based on the type of change requested. If Replication Server creates a new replication definition version, primary updates before the replication definition change request automatically use the old replication definition version, while primary updates after the replication definition change request use the new replication definition version.
Without these enhancements, to coordinate schema changes and replication definition changes, you must quiesce primary updates, wait until all the data associated with a primary table or stored procedure is processed through the entire replication system, shut down Replication Agent, alter the primary schema, alter the replication definition, alter any customized function strings, wait for the changes to replicate, alter the replicate schema, and then restart Replication Agent and resume primary updates.
See “Replication definition change request process,” in Chapter 9, “Managing Replicated Tables” in the Replication Server Administration Guide Volume 1 for the commands, procedures, and a user scenario for the enhanced replication definition change request process.
