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How the data challenge works (Online view)

Modifying the LHCb Bookkeeping Database CCRC’08 Preparatory Meeting Radu Stoica, CERN* 11 th January 2007 * On leave from IFIN-HH. How the data challenge works (Online view). A set of MDF files are produced in advance. They are copied to the Online storage in the pit.

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How the data challenge works (Online view)

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  1. Modifying theLHCb Bookkeeping DatabaseCCRC’08 Preparatory Meeting Radu Stoica, CERN* 11th January 2007* On leave from IFIN-HH

  2. How the data challenge works (Online view) • A set of MDF files are produced in advance. • They are copied to the Online storage in the pit. • A data simulator will create symbolic links to files and register them in the Run Database. • Files are copied to CASTOR and added to the LCG File Catalog. • The files are added to the LHCb Bookkeeping database. • Files are available for offline reconstruction in GRID. • After migration, files (or rather the links to them) can be deleted in the Online storage

  3. LHCb Bookkeeping Registration Mechanics: • A file is closed, migrated to CASTOR and added to LFC • The Data Mover generates a new XML request based on the file metadata from the Online Run Database. • An XMLRPC request is sent to the AMGA interface of the Bookkeeping database. • The request is saved by a daemon (“the BkkReceiver”) for asynchronous processing. • The XML request file is picked up by a manager and processed. The result of this operation can’t be propagated back!

  4. Information required • According to the DTD of the XML files for modifying the Bkk Db, the following parameters are needed: • Name, Location, Storage Element (required by database design for replicas) • MD5SUM, EventType, EventNumber, Size, FirstEventNumber, RunNumber, timestamp(s) • The schema of the database allows for new parameters. Other parameters should be decided based on the reconstruction needs. • A new configuration needs to be created for the raw event files

  5. Interfaces • All database content is available through the Run Database API • Interfaces for extracting data (have the same functionality): • XMLRPC • DIM • The database interface can be polled for files that can be added to the Bkk Db. The files become available after they are migrated to tape and added to the LFC. • If needed template script available.

  6. Open questions • File name conventions needed: • For files written on Online Storage (already there) • For files on the LFC • For the physical file names on CASTOR • How/when the Bookkeeping database will change? • How can we test the interface with Bkk Db.? • Is there anything else needed in the Bkk Db.?

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