Oracle Distributed Systems

Oracle8i Enhancements

Oracle8i enhancements to replication focus primarily on improved performance, simpler administration, and mass deployment (e.g., hundreds of updateable snapshots from a single master table):

• The generated replication apply packages (table_name $RP and table_name $RR) are internalized instead of PL/SQL packages—that is, they are written in C and compiled directly into the database engine. This results in faster execution and generation of replication support. In addition, the packages are more secure.

• Snapshot refreshes have been optimized to support refresh groups with up to 400 snapshots per group. In addition, the refresh algorithm has been modified to significantly reduce the number of round-trips required to perform a refresh.

• Snapshot deployment templates allow the DBA to control the contents of snapshot sites. The templates are defined at the master site and deployed to snapshot sites, as opposed to snapshot sites defining their own snapshots. This ensures a uniform configuration of all snapshot sites.

• Vertical partitioning of updateable snapshots. Note that vertical partitions must include all columns that comprise the master table’s primary key, and the columns that are not included must either be nullable in the master table or have default values assigned.