Upgrade of the ZEUS OO Tag Database for Physics Analysis at HERA
摘要
The object-oriented tag database of the ZEUS experiment at HERA is based on Objectivity/DB.It is used to rapidly select events for physics analysis based on intuitive physical criteria.The total number of events currently in the database exceeds 150 millionBased on the detector configuration different information can be stored for each event.A new version of the database software was recently released which serves clients on a multitude of batch machines,workgroup servers and desktop machines running Irix,Linuxand Solaris.This replaces an earlier version which was restricted to three SGI machines Multiple copies of the data can be stored transparently to the users for example if a new offline reconstruction of the data is in progress.A report is given on the upgrade of the database and its superior performance compared to the old event selection method.