[OSM-dev] Ways with 40k nodes, was: osmosis pgsql schema

Stefan de Konink stefan at konink.de
Fri Oct 31 16:48:55 GMT 2008


Matt Amos wrote:
> On Fri, Oct 31, 2008 at 4:06 PM, Stefan de Konink <stefan at konink.de> wrote:
>> Matt Amos wrote:
>>> i don't understand what you mean by a pyramid shape. the relations
>>> would be returned in the same order, regardless of the role tag,
>>> right? and you're not merging subtrees...?
>> My proposal would be merging subtrees, so they can store an highway with
>> 80km/h 100km/h zones in one relation as part of two subtrees (as
>> optimalisation), or multiple subtrees for each zone found.
> 
> very interesting... so are the subtrees explicitly merged (i.e: merged
> subtrees are marked "deleted" and no longer individually addressable)
> or implicitly (i.e: if A and B are subtrees of C, then i can ask for
> A, B or C and update any one of them and see the changes reflected in
> the other)?

This advanced relation stuff only in brains and on paper. But I wanted 
to take a completely different approach to versioning. I have asked the 
authors of the database software I use if it is possible to create a 
view based on a certain moment in time, what the database looks like at 
that time. (copy-on-write, is basically already what happens under the hood)

In that case only *one* view needs to be maintained, and no application 
layer management. This is something I'll be working on later, the 
application; handler_osm is just a very good excuse to test things out 
with real life data.


Stefan




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