[OSM-dev] database growth on updated partial import
osm at stephans-server.de
Tue Aug 24 08:53:05 BST 2010
Frederik Ramm wrote:
> Stephan Knauss wrote:
>> But there is a "id" column. I thought I could match all ids that are
>> not included in the _line _polygon _roads tables.
> Careful with that; that would also delete ways which are inside your
> bbox and which don't have any tags that are interesting to osm2pgsql -
> but such a way might well be used as a member in a polygon relation
> (which you could check by looking at the relations table) or it could
> *become* a member of such a relation in the future (in that case you
> would receive a diff with the new relation, but the way would be assumed
> to be already present).
You're right. I missed the point that not all ways might be present.
So the wasy to repair this might be to iterate over the ways and check
the existence of their nodes in the _nodes table. In case there is no
match it can be removed.
I wonder whether this is faster than a reimport of the bbox.
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