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

Matt Amos zerebubuth at gmail.com
Fri Oct 31 14:45:21 GMT 2008


On Fri, Oct 31, 2008 at 12:55 PM, Stefan de Konink <stefan at konink.de> wrote:
> Andy Allan wrote:
>> No, hang on, that would be daft. I'd be better off making subtrees
>> limited to about 1000 nodes or thereabouts, to improve the efficiency
>> of partial checkouts. So then I would have sensibly sized subtrees
>> (lets call them 'ways') and the master super-tree (lets call it a
>> relation).
>
> You miss the point of rewriting ways into relations. It will reduce the
> code complexity and database complexity of all operations significantly.

quick question: if your schema used ordered relations instead of ways,
do you have an unordered relation type as well?

> The amount of tables is reduced, that means the amount of joins are
> reduced. And the indices required for database searches are now more
> efficient. Queries therefore get shorter, no need for a specific way
> renderer.

except when your relation doesn't relate linear features.

cheers,

matt




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