3/24/2003CHEP'03, La Jolla, USA Object Database for Constants: The common CLEO Online and Offline solution Hubert Schwarthoff Cornell University With N. Adam, S. Lee Cornell University, USA

3/24/2003CHEP'03, La Jolla, USA1 Contents CLEO III / CLEO-c CLEO software: The Constants database The Constants system redesign Experiences

3/24/2003CHEP'03, La Jolla, USA2 Introduction CLEO III until 2003: Y(2,3,4,5S), etc  Crystal E.M. calorimeter  Tracking drift chamber  Muon chambers  RICH  SVX CESR-c: Charm factory  superconducting wigglers  Low energy: 11 GeV → 3 GeV  Luminosity > cm -2 s -1 Spring 2003: CLEO-c detector  SVX → ZD  30M DD, 1.5M D s D s, 1B J/Ψ

3/24/2003CHEP'03, La Jolla, USA3 The CLEO III detector

3/24/2003CHEP'03, La Jolla, USA4 CLEO computing Online computing  ~300k channels  Readout: 30 Motorola PowerPC (VxWorks, VME)  17 VME crates, 12 FASTBUS  Standard Ethernet – TCP/IP  Data rate < 9MB/s through EventBuilder < 100 Hz  Storage on AIT tape robot Offline computing C.Jones:”Reconstruction and analysis on demand” Thu 1:50pm Category 7

3/24/2003CHEP'03, La Jolla, USA5 Software system C, C++, Java, on  VxWorks 5.3 (Online)  solaris 2.8  Windows 2000 (GUI, Online)  osf 4.0, linux RH Offline, no database server Online database (Objectivity 7) Alarms, RunStatistics, Constants, … via CORBA server CORBA: VisiBroker 5, Mico (osf, linux) Online: One system does it all  Readout, SlowControl, monitoring, database, RunControl, …

3/24/2003CHEP'03, La Jolla, USA6 CLEO III constants database User writes bdl file: Build system auto-generates client and server C++ and java code.  Common for Online and Offline code systems Name: RICHChannel { UInt32 ChannelAddress UInt16 Crate SelectBy UInt16 Threshold UInt16 Pedestal } Constants OfflineOnline

3/24/2003CHEP'03, La Jolla, USA7 Online and Offline Offline management:  User submits constants as ASCII file (no user write access)  Management system installs constants, with safeguards. One system for  Detector configuration  Detector calibration  Detector diagnostics  Data reconstruction  Data analysis  Monte Carlo All the above use the same C++ interface for constants access.

3/24/2003CHEP'03, La Jolla, USA8 Database operation Need several DBs: Designate Online database as master All of CLEO computing needs access to constants → Need mirror databases for processing  Update regularly and automatically (special application)  Prevent interference with Online operation  Allow easy handling (documentation, troubleshooting)

3/24/2003CHEP'03, La Jolla, USA9 Redesign - why Original system had been invented with wrong requirements: Usage as one constants object, but data is stored as many objects (1 per line, up to lines). Example: RICHChannel constants object: Version: 1784, Created 11/03/ :32:22 ChannelAddressThresh Crate Pedestal Inefficient and not utilized, wastes space. DB Version: /03/ :32:

3/24/2003CHEP'03, La Jolla, USA10 Search is often linear (data is not organized). - Inefficient, eats CPU. Address space limited: Can only have ~ 32k versions of one type. - We have already reached this limit. ~200 types were combined to 13 groups, but that was too cumbersome to manage Redesign - why?

3/24/2003CHEP'03, La Jolla, USA11 The new system Rewrite of all database code. Store one constants version as one db object (e.g. put all lines in one object). Example: RICHChannel constants object: Version: 1784, Created 11/03/ :32:22 ChannelAddressThresh Crate Pedestal DB Version: /03/ :32: …

3/24/2003CHEP'03, La Jolla, USA12 The new system Organize data according to usage. Separate constants versions from usage information. Completely avoid linear searches - use management structures: indexed lists, hash maps. CORBA → change database system without touching other software.

3/24/2003CHEP'03, La Jolla, USA13 New system: performance Time to load 1 constants object from database (CORBA): > 5 times faster N.Adam (1 entry = 10 min interval) Old New

3/24/2003CHEP'03, La Jolla, USA14 Experiences Objectivity/DB  LHC and BABAR abandon their large databases. Support?  Commercial = black box  See D.Riley: “Dynamic management of CLEO III event data”, Tue 5:30pm Category 8 VisiBroker (CORBA)  No osf (use mico, only singlethreaded)  Version 4 unstable (both solaris and VxWorks) Linux: Difficult with commercial software

3/24/2003CHEP'03, La Jolla, USA15 Future plans CLEO-c will start operation Jul Offline constants system will manage all types independently (summer 2003) → Much easier management, more flexibility Upgrade VxWorks CORBA version System will be challenged with higher data rates (300 Hz) for J/Ψ data