[fdo-trac] #47: More optimized SDF reader handling of string properties and other performance enhancements

[FDO]

#47: More optimized SDF reader handling of string properties and other
performance enhancements
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   Reporter:  badreddinekaroui  |       Owner:  Badreddine Karoui
       Type:  enhancement       |      Status:  new              
   Priority:  minor             |   Milestone:  3.3.0            
  Component:  SDF Provider      |     Version:  3.3.0            
   Severity:  3                 |    Keywords:                   
External_id:                    |  
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 This enhancement addresses 2 main issues:
 1) A regular FDO client would use the class definition to discover and
 read the property values of a given class. As a result, after each
 ReadNext the properties are accessed in the order they added to the
 property definition collection of the class. One of the internal functions
 performs a linear search for every property. This change will eliminate
 the linear search by keeping a pointer to the last accessed property.

 2) The second change implements a more efficient buffer cache for string
 properties and minimize memory re-allocation over the lifespan of the
 feature reader.

 The above 2 changes have a significant performance improvement. For one of
 the test SDF files with 2 millions records the time to access all the
 records changed from ~140 sec to ~45 sec.

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Ticket URL: <http://trac.osgeo.org/fdo/ticket/47>
FDO <http://fdo.osgeo.org/>
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