On-change Publishing of Database Resident Control System Data
C.Roderick, R.Billen, R.Billen* (CERN)
The CERN accelerator control system is largely data driven, based on a distributed Oracle database architecture. Many application programs depend on the latest values of key pieces of information such as beam mode and accelerator mode. Rather than taking the non-scalable approach of polling the database for the latest values, the CERN control system addresses this requirement by making use of the Oracle Advanced Queuing - a Java Messaging Service (JMS) implementation - to publish data changes throughout the control system via the CERN Controls Middleware (CMW). This paper will describe the architecture of the system, the implementation choices and the experience so far.