Speaker
Mr
Michael DePhillips
(BROOKHAVEN NATIONAL LABORATORY)
Description
The STAR experiment at Brookhaven National Laboratory's Relativistic Heavy-Ion
Collider (RHIC) has been accumulating 100's of millions events over its already 5
years running program. Within a growing Physics demand for statistics, STAR has more
than doubled the events taken each year and is planning to increase its capability by
an order of magnitude to reach billion events capabilities by 2008.
Under such a rate stress imposed by the event rate, the run condition support and
database back-end needed to rapidly mature to follow the demand while preserving user
convenience and time evolution but also allow for in depth technology changes as
required.
In this talk, we will present the use of relational databases in STAR organized as a
three tier architecture model: a front-end user interface, a middle tier homegrown
C++ library (StarAPI) that handles all of the unique requirements arising from an
active experiment, and finally, the lower level DBMS requirements and data storage.
Paramount considerations include maintaining flexibility and scalability with modular
construction and consistent namespace; ensuring long-term analysis integrity with
three-dimensional time-stamping or range of validity which in turn allows for solid
schema evolution; and ensuring uniqueness with expanded primary keys.
We will identify and discuss trade-offs and challenges that have occurred during the
evolution of our experiment, and specifically the challenge introduced by detectors
which could only be described in terms of million leaves within an ultra-fine
granularity of calibration values.
Primary authors
Dr
Jerome LAURET
(BROOKHAVEN NATIONAL LABORATORY)
Mr
Michael DePhillips
(BROOKHAVEN NATIONAL LABORATORY)
Co-authors
Dr
Jefferson PORTER
(University of Washington)
Mr
Victor Perevoztchikov
(BROOKHAVEN NATIONAL LABORATORY)
