LAT Data Handling

Data Access from the LAT

apply queries to ntuples and produce output as FITS, trees or ntuples
Root I/O has features we should be able to exploit
- read only branches involved in the query before selecting successful rows
  - should be "free" to carry many ntuple columns
  - only paying disk space, not access time
- random access to events (rows) inside files
- can index files internally to attach event ID to row number in the files
- extract tree events from ntuple index
probably need to put ntuples on the query server for best access
if needed, we can investigate Root's PROOF parallel query system
- automagically breaks up and routes queries to different nodes and reassembles the answer before returning them to the user