InfiniDB
  uses Extent Maps to retrieve data. Data is stored in extents and
  each extent is a logical block of space that holds the same
  number of rows.
  
  The Extent Map catalogs all extents and their corresponding
  blocks. The Extent Map also maintains minimum and maximum values
  for a column’s data within an extent.
  
  The Extent Map lets InfiniDB to retrieve only the blocks
  needed to satisfy a query. There is another benefit – that of
  logical range partitioning. This is accomplished via the minimum
  and maximum values for each extent that are contained within the
  Extent Map. Extent elimination is first accomplished in InfiniDB
  via the column-oriented architecture (only needed columns are
  scanned), but the process is accelerated because of the logical
  horizontal partitioning that is implemented in the Extent Map. So
  only the needed sections of the column are read. …
    
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            Jun
            
        
        
        09
            2010
        
    
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