[OSM-dev] New, faster, planet dump tool

Brett Henderson brett at bretth.com
Tue Sep 25 13:34:10 BST 2007

Jon Burgess wrote:
> I wrote this version because it looked like the runtime of planet.rb
> was becoming an issue again. The code should be faster than Osmosis
> but I have not run a specific test with this current data set. It
> should be the bzip2 compression time which will dominate the planet
> dump time.
> planet.c and osmosis do have slightly different aims. The osmosis code
> is a far more generic implementation but I suspect its speed will
> never be able to match a custom C implementation. On the other hand,
> generating diffs directly from the DB using Osmosis would be far
> quicker then using the current planet dump + planetdiff tools.
> I'd be happy to use either tool provided they both achieve the same
> result within time and memory constraints.
> Anoner possibility is to use the planet.c code to stream a DB dump
> into the PostgreSQL mapnik database. Avoiding the bzip2 compression
> should allow this to be done quite rapidly. We could then update the
> Mapnik layer more frequently than the formal weekly planet dump.
Is there any way to feed changes into the mapnik db instead of doing a 
complete import?  I seem to remember a previous email where you 
mentioned you'd need to store some translation data between the osm and 
mapnik representations which is currently held in RAM ...  From memory 
the reason for RAM is speed, but if the changes are small (relatively to 
total data set) then it may be worthwhile having a db based intermediate 

If possible, it might allow mapnik to be updated in near real-time.

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