[postgis-devel] [PostGIS] #985: [raster] ST_Count

[PostGIS]

#985: [raster] ST_Count
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  Reporter:  dustymugs       |       Owner:  dustymugs    
      Type:  task            |      Status:  reopened     
  Priority:  medium          |   Milestone:  PostGIS 2.0.0
 Component:  postgis raster  |     Version:  trunk        
Resolution:                  |    Keywords:  history      
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Comment(by dustymugs):

 Replying to [comment:24 pracine]:
 > 1) We should not have to deserialize the whole raster to get the raster
 georeferencing properties. We should have a rt_raster_deserialize_header
 function. That would certainly make all all the getter faster. It is
 possible to deserialize only part of the raster? It seems to me that just
 copying rt_raster_deserialize until the first memcpy would make a working
 rt_raster_deserialize_header function.
 >

 We could just extend rt_raster_deserialize by adding a parameter flag
 "header_only" to shortcut the function.  That would reduce the potential
 performance hit.  If Jorge is reading this, I'd like him to chime in
 before I make changes to that function and any calls to that function.

 > 2) We can not push the preceding logic too far and remove all the
 metadata getters. On the other side we could have a more efficient C
 implementation of ST_Metadata and ST_BandMetadata.
 >
 > Would that fill your needs?

 Extending rt_raster_deserialize to only deserialize the header should
 minimize some bottlenecks.

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Ticket URL: <http://trac.osgeo.org/postgis/ticket/985#comment:25>
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