Replication Server provides four different serialization methods for specifying the level of parallelization. The serialization method you choose depends on your replication environment, and the amount of contention you expect between parallel threads.
Each serialization method defines the degree to which a transaction can start before it must wait for the previous transaction to commit.
alter connection to SYDNEY_DS.pubs2 set dsi_serialization_method to 'wait_for_commit'
While providing commit consistency, the serialization method defines whether the beginning of the transaction waits for the previous transaction to become ready to commit or if the beginning of the transaction can be processed earlier.