High-Volume Adaptive Replication (HVAR) uses compilation and bulk-apply processes that result in data reduction and achieve better performance compared to continuous replication mode, which sends each replication operation to the replicate database directly, row-by-row and in log order.
Compilation – rearranges replicate data by clustering it by each table, and each insert, update, and delete operation, then compiling the operations into net-row operations.
Bulk apply – applies the net result of the compilation operations in bulk using the most efficient bulk interface for the net result. Replication Server uses an in-memory net-change database to store the net row changes which it applies to the replicate database.
Instead of sending every logged operation, compilation removes all the intermediate operations and sends only the final states of a replicated transaction. Depending on the application, this generally means a much smaller amount of data is processed.
As Replication Server compiles and combines a larger number of transactions into a group, bulk operation processing improves; therefore, replication throughput and performance also improves. You can control the amount of data that is grouped together for bulk apply by adjusting group sizes.
HVAR is especially useful for creating online transaction processing (OLTP) archiving and reporting systems where the replicate databases have the same schemas as the primary databases.
See “High Volume Adaptive Replication to Adaptive Server” in Chapter 4, “Performance Tuning” in the Replication Server Administration Guide Volume 2.
Replication Server uses the rs_tbconfig table to store support table-level configuration parameters, and the ref_objowner and ref_objname columns in the rs_columns table to support referential constraints.
See Chapter 8, “Replication Server System Tables” in the Replication Server Reference Manual for full table descriptions.