80 likes | 87 Views
This meeting aims to define a strategy for the bookkeeping and tag database, focusing on the development of TagCollections, specialized collections of event tags with links to the event data. The meeting will also explore possibilities for a single database for everything or a hybrid system with various technologies.
E N D
Bookkeeping and Tag Database Define a strategy Program of Work Meeting, June 28-19, 2000 P. Mato, CERN P. Mato, CERN
Event DataSet RunParam ProdParam Run MCRun TagCollection Data structures above Event Data • Entities identified • DataSet collection of events • Run a sub-type of DataSet • MCRun a sub-type of DataSet • TagCollection a collection of event tags with a link to the event. • An event can only be in one DataSet • An event can be associated to many TagCollections * * * * P. Mato, CERN
Connection to GAUDI • The EventSelector is in charge of performing the selection based on a given criteria • Today: Filename, Tape number, JobId, First event, Number of events, etc. • Tomorrow: Complex queries to tag and dataset databases • The EventSelector returns a pointer (iterator) to the Event header. • This pointer is used to get the various event objects by the PersistencySvc selection criteria event iterator Event Selector DataSets TagCollections P. Mato, CERN
TagCollection • The idea is to create specialized (LHCb general or private) collections of event tags with a pointer to the event head location dataSet dataSet Event dataSet trType visE muCand eCand XID Event trType visE muCand eCand XID Tag Collection trType visE muCand eCand XID Event trType visE muCand eCand XID Event few 100’s bytes P. Mato, CERN
Event DataSet RunParam ProdParam Run MCRun TagCollection Current Status Not existing * * * Current Bookkeeping Database Sicb Files (tapes) * P. Mato, CERN
Event DataSet RunParam ProdParam Run MCRun TagCollection Possibility A Single database for everything (Objectivity?, Oracle?) • Very attractive • single technology • full navigability • integrity and consistency • Advocated by RD45 (CMS) • Not very successful with Objectivity • Several federations • import/export databases • database catalog management * * * * P. Mato, CERN
Event DataSet RunParam ProdParam Run MCRun TagCollection Possibility B • Hybrid system • Various technologies • Expertise required • Advocated by ROOT • (excluding TagCollection) • Very powerful queries to the event tags are possible • Fits well with the GAUDI architecture DB with TagCollections and DataSets * * * Event Data Files * P. Mato, CERN
Proposal • Strategy: Study A and B • Develop TagCollection • Using standard N-tuples (PAW or ROOT based) • Using a relational Database (Oracle based) • Extent current EventSelector to include sophisticated queries to TagCollections • Performance comparisons between A and B P. Mato, CERN