[fdo-trac] #777: Improve WFS memory usage

[FDO]

#777: Improve WFS memory usage
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   Reporter:  gregboone     |       Owner:  gregboone
       Type:  defect        |      Status:  new      
   Priority:  major         |   Milestone:  3.7.0    
  Component:  WFS Provider  |     Version:  3.6.0    
   Severity:  2             |    Keywords:           
External_id:                |  
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 Hi,

 I'm looking into a problem in an application using the WFS provider,
 whereby if it is trying to process a large number of features it uses a
 large amount of memory - even though the application itself only ever
 needs one top-level feature to be in memory at a time - resulting in a
 limit to the size of data that can be processed without the application
 crashing. As far as I can determine, this isn't a leak. This is happing
 with builds done against 3.2 and 3.6 releases of FDO.

 I had a look at the source code: when the IFeatureReader interface is used
 to iterate over the available features it only allows access the the
 current feature, but it appears to be maintaining a collection of every
 feature seen. At least, this was the impression I got from
 FdoXmlFeatureReaderImpl::ReadNext - with all the top-level features ending
 up in m_featureCollection.

 So, the questions I have are:
 (a) Am I correct in thinking that it is holding on to every feature
 processed by the reader?
 (b) If so, is there any way of stopping it from doing this?

 Thanks,
 Robin Newton

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Ticket URL: <http://trac.osgeo.org/fdo/ticket/777>
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