Conclusions of WP1-WP2 bi-lateral meeting

1
Conclusions of WP1-WP2 bi-lateral meeting

• Massimo Sgaravatto
• INFN Padova

2
Issues

• WP2 value estimators for query optimization
  must be plugged into WP1 Accounting structure
• Contacts between Trento (WP2) and Torino (WP1)
  groups
• WP2 will propose some extensions to JDL to
  describe the file access characteristics, that
  need to be supplied by the user

3
Issues

• WP2 will try to understand how SE contents can be
  accessed via regular POSIX I/O for release 2
• Extending an existing SE file pin (from
  WP2/WP5) ?
• Query optimization APIs

4
APIs

• PFN_time getAccessCost(LFN, CE, protocol)
• Invoked by RB for each candidate CE
• Used to find the best CE wrt data location
• Doesnt trigger any data transfers

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APIs

• PFN getBestFile(LFN, protocol)
• Invoked by application when the file is needed
• Can trigger a data transfer
• Blocking API
• InitFilePrefetch(LFN, CE, Protocol)
• Non-blocking call to start best file prefetch
  operation
• Invoked by RB or by first instruction of
  application ?
• Useful to get the files ready before they are
  actually accessed (useful in particular for long
  data transfer)
• CancelFilePrefetch()

6
Schedule

• Main functionalities of these APIs supposed to
  be implemented in Java by May 31, 2002