Object Database for Constants: The common CLEO Online and Offline solution

1
Object Database for Constants The common CLEO
Online and Offline solution

• Hubert Schwarthoff
• Cornell University

With N. Adam, S. Lee Cornell University, USA
2
Contents

• CLEO III / CLEO-c
• CLEO software The Constants database
• The Constants system redesign
• Experiences

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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 gt 1032 cm-2s-1
• Spring 2003 CLEO-c detector
• SVX ? ZD
• 30M DD, 1.5M DsDs, 1B J/?

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The CLEO III detector
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CLEO computing

• Online computing
• 300k channels
• Readout 30 Motorola PowerPC (VxWorks, VME)
• 17 VME crates, 12 FASTBUS
• Standard Ethernet TCP/IP
• Data rate lt 9MB/s through EventBuilder (solaris)
  _at_ lt 100 Hz
• Storage on AIT tape robot
• Offline computing

C.JonesReconstruction and analysis on
demand Thu 150pm Category 7
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Software system

• C, C, Java, on
• VxWorks 5.3 (Online)
• solaris 2.8
• Windows 2000 (GUI, Online)
• osf 4.0, linux RH 8.0 - Offline, no database
  server
• Online database (Objectivity 7)Alarms,
  RunStatistics, Constants, via CORBA server
• CORBAVisiBroker 5, Mico (osf, linux)
• Online One system does it all
• Readout, SlowControl, monitoring, database,
  RunControl,

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CLEO III constants database

• User writes bdl file
• Build system auto-generates client and server C
  and java code.
• Common for Onlineand Offlinecode systems

Name RICHChannel UInt32 ChannelAddress
UInt16 Crate SelectBy UInt16
Threshold UInt16 Pedestal
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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.

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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)

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Redesign - why

• Original system had been invented with wrong
  requirementsUsage as one constants object, but
  data is stored as many objects (1 per line, up to
  230000 lines).Example RICHChannel constants
  objectVersion 1784, Created 11/03/1999
  183222ChannelAddress Thresh Crate
  Pedestal67895304        4 2199
  221067895297    4 2219 220967895299 4
  2204 219467895308 4 2218
  2208...- Inefficient and not utilized, wastes
  space.

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Redesign - why?

• Search is often linear (data is not organized).-
  Inefficient, eats CPU.
• Address space limitedCan only have 215-1 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

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The new system

• Rewrite of all database code.
• Store one constants version as one db
  object(e.g. put all 230000 lines in one
  object).Example RICHChannel constants
  objectVersion 1784, Created 11/03/1999
  183222ChannelAddress Thresh Crate
  Pedestal67895304        4 2199
  221067895297    4 2219 220967895299 4
  2204 219467895308 4 2218
  2208...

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The new system

• Organize data according to usage.Separate
  constants versions from usage information.
• Completely avoid linear searches- use management
  structuresindexed lists, hash maps.
• CORBA ? change database system without touching
  other software.

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New system performance

• Time to load 1 constants object from database
  (CORBA)gt 5 times faster

(1 entry 10 min interval)
New
Old
N.Adam
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Experiences

• Objectivity/DB
• LHC and BABAR abandon theirlarge
  databases.Support?
• Commercial black box
• See D.Riley Dynamic management of CLEO III
  event data , Tue 530pm Category 8
• VisiBroker (CORBA)
• No osf (use mico, only singlethreaded)
• Version 4 unstable (both solaris and VxWorks)
• Linux Difficult with commercial software

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Future plans

• CLEO-c will start operation Jul 1 2003
• 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/? data