[OSM-dev] Various OSM troubles

SteveC steve at asklater.com
Tue Jan 9 12:17:07 GMT 2007


* @ 08/01/07 04:17:20 PM ludwigbrinckmann at gmail.com wrote:
> >
> >
> >On the other hand there is a limit in size, but you probably will only see
> >it
> >if you are in a not so well filled area like Africa, ...
> 
> 
> True. Maybe we should first find the bottleneck before looking for

The bottleneck is that large(r) map requests lock off the node table for
a while when reading it so uploading a node block until the read is
done. The other one is that the traces SQL is a bit crap and locks off
the user table in a similar way (and every request needs the user table)
Lots of this is fixed in the rails port, feel free to hack on it.

> In the meantime have just been a bit browsing through the DB code and one
> thing I noticed is -- correct me if I am wrong -- that OSM does not use the
> MySql spatial extensions to represent the geometries, and thus cannot use
> spatial indices on the data.

See threads past on why it's not as quick as you think.

You're welcome to take planet.osm and the (_rails_) code and make it all
use geo columns and send the patch here :-)

have fun,

SteveC steve at asklater.com http://www.asklater.com/steve/




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