[postgis-devel] [PostGIS] #230: Put in costs in _ST and possibly other functions

[PostGIS]

#230: Put in costs in _ST and possibly other functions
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  Reporter:  nicklas  |       Owner:  robe                     
      Type:  defect   |      Status:  assigned                 
  Priority:  medium   |   Milestone:  postgis 1.5.0            
 Component:  postgis  |     Version:  1.4                      
Resolution:           |    Keywords:  st_dwithin st_expand bbox
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Comment (by nicklas):

 OK, I see

 cost 1 in postgresql 8.3 and 8.4 is just default values.
 From what comes cost 1 in 8.3, 8.4 installations, it is not mentioned in
 postgis.sql.in.c?

 Couldn't we put the costs in a separate sql-file with every function
 represented like:
 {{{
 ALTER FUNCTION _ST_DWithin(geometry,geometry,float8) cost 100;
 }}}

 I can see some advantages of that.[[BR]]

 1) in installation just one check for postgresql version and if 8.3 or
 above --> run costs.sql after postgis.sql [[BR]]
 2) users could easily move customized costs from one installation to
 another.[[BR]]
 3) we could put new recommended costs in the wiki for example, between
 releases.[[BR]]

 Espescially in the beginning I guess there will be some calibration in the
 recommended costs. 2 and 3 above is of course not depending on that we
 distribute costs.sql in the installation, but then the user have one place
 to play with the costs and a recommended way of storing the customizing by
 editing the costs.sql.

 Wouldn't it be easier too, to try something like Kevin suggesting of
 getting costs from statistics if they where held separately.

 /Nicklas

-- 
Ticket URL: <http://trac.osgeo.org/postgis/ticket/230#comment:17>
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