[mapguide-trac] #1647: King.Oracle layer previews can render feature source indefinitely busy and crash the mapagent handler

[MapGuide Open Source]

#1647: King.Oracle layer previews can render feature source indefinitely busy and
crash the mapagent handler
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   Reporter:  jng        |       Owner:       
       Type:  defect     |      Status:  new  
   Priority:  high       |   Milestone:  2.2  
  Component:  Map Agent  |     Version:  2.2.0
   Severity:  blocker    |    Keywords:       
External_id:             |  
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 We've discovered a serious defect with the King.Oracle provider with
 regards to the SpatialExtents() aggregate function.

 Instead of returning one result (the computed MBR) of a given feature
 class, it instead returns the same computed MBR for each result in the
 feature class!

 This problem can easily manifest itself when previewing a King.Oracle
 based Layer Definition in Maestro or MapGuide Studio as this aggregate
 function is used to get a preview-ready MBR.

 For a moderately large Oracle table, this will crash the mapagent handler
 and send the King.Oracle feature source into a semi-permanent locked state
 in the feature source cache (ie. Attempts to overwrite the feature source
 will throw "resource is busy" errors).

 When you do the layer preview, the access.log file is flooded with
 GetDataRows() calls, which is the provider returning the same MBR for each
 row in the oracle table.

 A proposed solution has already been given to Haris to fix this defect in
 the provider. This ticket is simply to indicate the release-blocking
 severity of this defect.

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Ticket URL: <http://trac.osgeo.org/mapguide/ticket/1647>
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