Mission Critical Database for SPS Accelerator Measurements

R. Billen, E. Hatziangeli, I. Laugier, I. Reguerro, N. Segura

CERN- European Laboratory for Particle Physics

In order to maintain an efficient control over the hadron and lepton beams in CERN's SPS accelerator, beam parameters such as intensities, positions and losses need to be rapidly available in the SPS control room to allow the operators to monitor, judge and act on beam physics conditions. For the 1994 SPS startup, a completely new and redesigned measurement system was introduced based on client and server C-programs running on UNIX-workstations. The kernel of this new measurement system is an on-line ORACLE database. The NIAM method was used for the database design as well as a technique to tag synchronized data with timeslots instead of timestamps. A great attention was paid to proper storage allocation for tables and indices since this has a major impact on the efficiency of the database, due to its time-critical nature. Many new features of ORACLE7 were exploited to reduce the surrounding software. During the 1994 SPS physics run, this new measurement was commissioned successfully and the implemented infrastructure proved to be acceptably reliable. Hence, for the 1995 startup, the size of the measurement system was increased by a factor of 20 in data traffic terms to fulfill a variety of measurement needs. This proliferation of measurements beyond the initial scope showed the correct design of the system, as well as the performance limitations within the actual hardware configuration. This paper describes the overall design and discusses performance issues of this critical system.