[OSM-dev] Reducing osm2pgsql memory usage using a database method
Joerg Ostertag (OSM Munich/Germany)
openstreetmap at ostertag.name
Sun Mar 11 09:45:06 GMT 2007
On Saturday 10 March 2007 22:52, Frederik Ramm wrote:
> > 1. We can re-write osm2pgsql in c++ and take advantage of dynamic
> > structures e.g std::map, safe formatting and casting
> > boost::lexiacal_cast, boost::format and more.
I think it would be great if we just could precalculate the planet.osm to a
geo-sql format and put it on the server for download. If we do this
automagically after creation of planet.osm it would ease things a lot for
> Hate to spoil your fun & don't want to start an advocacy debate here &
> am a C++ user myself BUT (1) hash tables etc. are readily available in
> plain C (glib), and (2) if you need flexibility why don't you do the
> importer in Perl?
There are several perl interface to osm, but working with planet.osm in perl
- takes 40 minutes only for reading
- takes 100Bytes of memory for each node stored in memory.
Which is more than 10 times more than really needed.
And if you try to use something like a tied has ...
- It only will take 10 hours to complete reading only
Well this doesn't seem to be the right way into the future.
Everything i tried up to now either would need >4GB RAM in the future, or is
Oh the values above are with a Hyperthreading 3GHz 2BG RAM Machine.
This is why for GPSDrive i currently tend to precalculate the SQL stuff and
make it available on the Server and tend to use a C Program in the long term.
Jörg (Germany, Munich)
TeamSpeak2: ts2.ostertag.name, user: tweety, Channel: "GPS Drive"
Tel.: +49 89 420950304
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