Oracle Streams: A High Performance Implementation for Near Real Time Asynchronous Replication

The authors present the architectural design and recent performance optimizations of a state of the art commercial database replication technology provided in Oracle Streams. The underlying design of Streams replication is a pipeline of components that are responsible for capturing, propagating, and applying Logical Change Records (LCRs) from a source database to a destination database. Each LCR encapsulates a database change. The communication in this pipeline is now latch-free to increase the throughput of LCRs. In addition, the apply component now bypasses SQL whenever possible and uses a new latch-free metadata cache.