Speaker
Dr
Douglas Smith
(STANFORD LINEAR ACCELERATOR CENTER)
Description
The data production and analysis system of the BaBar Experiment has evolved through a
series of changes from a day when the first data were taken in May 1999. The changes,
in particular, have also involved persistent technologies used to store the event
data as well as a number of related databases. This talk is about CDB - the
distributed Conditions Database of the BaBar Experiment. The current production
version of the database was deployed in 2002. One of the principles behind the design
of CDB was its ability to deal with multiple persistent technologies to store the
data. Originally, CDB was implemented using Objectivity/DB - the commercial OODB. Two
new implementations of CDB, based on ROOT I/O and MySQL, are now available. All three
are going to coexist and be used in the Experiment for a while, targeting various
groups of users. This problem poses rather interesting challenges in managing this
hybrid system in a highly distributed environment of the Experiment. The talk will
cover key design decisions in a foundation of the database, its flexible API designed
to cope with multiple persistent technologies, an information flow (transformation)
between different formats of data, and other non-trivial aspects of managing this
complex system.
Primary author
Mr
Igor BaBar Computing Group
(LBL)
