[OSM-talk] OGL, OSM, NASA
steve at asklater.com
Tue Apr 25 13:18:46 BST 2006
* @ 25/04/06 01:15:45 PM sxpert at esitcom.org wrote:
> 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)
Actually those queries are quicker than you might think. You're right
(as we chatted on IRC, IIRC) that having a flag for the latest data or
having it in a seperate table might speed it up, but they have their own
complexities like locking.
> 2) not using a geometric-aware database engine (1 stems partly from this)
Again, can be faster but has it's own complexities. geomfromtext etc can
take a lot of time
> 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
/me nods. Feel free to hack on it.
I'd add 4) the db machine is way underspecced.
SteveC steve at asklater.com http://www.asklater.com/steve/
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