Propagation Modes

You can set the propagation mode for a scheduled link when you use the Replication Setup Wizard to set up your replication environment or by editing the scheduled link (Viewing and Editing a Scheduled Link).

The choices for propagation mode are:

Serial Propagation: With serial propagation, Oracle asynchronously propagates replicated transactions, one at a time, in the same order of commit as at the originating site.

Parallel Propagation: With parallel propagation, Oracle asynchronously propagates replicated transactions using multiple, parallel transit streams for higher throughput. When necessary, Oracle orders the execution of dependent transactions to ensure global database integrity. When you specify parallel propagation with Oracle Enterprise Manager:

• Specify 1 to use parallel propagation with only one parallel process.

• Specify greater than one for parallel propagation with the number of parallel processes specified.

• Specify 0 (zero) for serial propagation.

For most environments, 1 is the best setting. If set to greater than 0, then make sure the initialization parameters PARALLEL_MIN_SERVERS and PARALLEL_MAX_SERVERS are configured correctly.

PARALLEL_MIN_SERVERS specifies the minimum number of parallel execution processes for the instance. This value is the number of parallel execution processes Oracle creates when the instance is started. If you use parallel propagation, make sure you have at least one process for each stream.

PARALLEL_MAX_SERVERS specifies the maximum number of parallel execution processes and parallel recovery processes for an instance. As demand increases, Oracle will increase the number of processes from the number created at instance startup up to this value. If you use parallel propagation, make sure the value of this parameter is set high enough to support it.