[OSM-talk] [OSM-dev] donating read-only api-mirrors

Frederik Ramm frederik at remote.org
Fri Feb 6 18:06:45 GMT 2009


Hi,

Marcus Wolschon wrote:
> So...why is it that you hold the result-set of the nodes-query in memory
> again?

While not mandated by the XML structure, the XML document we return is 
usually sorted - nodes, ways, relations, each in ascending ID order. 
Because a way or relation may require additional nodes to be included 
that lie outside of the bounding box, we can only return the nodes after 
we have processed ways and relations.

For the computer literate, all this information is available here:
http://trac.openstreetmap.org/browser/sites/rails_port/app/controllers/api_controller.rb#L87

This could of course be alleviated by allowing the XML to be mixed, i.e. 
some nodes, then some ways, then some more nodes and so on. Then, one 
would only have to find a good way to have Ruby stream the results, 
something which is, as far as I understand from previous posts on this 
list, not a core feature of Ruby.

Bye
Frederik

-- 
Frederik Ramm  ##  eMail frederik at remote.org  ##  N49°00'09" E008°23'33"




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