[OSM-talk] OGL, OSM, NASA

Raphaël Jacquot sxpert at esitcom.org
Tue Apr 25 13:15:45 BST 2006


Christopher Schmidt wrote:
> On Tue, Apr 25, 2006 at 10:16:38AM +0100, Nick Whitelegg wrote:
> 
>>Because parsing the planet.osm was a rather slow job it only contains an 
>>area approximating to the UK and France at the moment, but will contain 
>>the whole lot in due course.
> 
> 
> Really? I parsed segments and nodes out of the planet.osm data in
> 43seconds, and loaded them into a database in 10 minutes. (Then exported
> them and loaded them into another in another 5 minutes.)
> 
> What part is slow?
> 

guess he wasn't using libxml2's sax interface :D

imho, after reading the code that does the drawing, I'm pretty sure the 
problems we face are linked to the sql and the database server.

I'll attribute the slowness to

1) insane SQL queries ( see 
http://trac.openstreetmap.org/browser/ruby/api/wms/streets.pl#L52 for a 
good example)

2) not using a geometric-aware database engine (1 stems partly from this)

3) from 2, not using proper indexes on the things that matter most, 
specifically indexes that would greatly accelerate requests looking for 
stuff that is within a 2D box






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