Lennard schrieb:
On 9-5-2010 23:15, Lennard wrote:
This is true for the hstore import anyway. Or does --extra-attributes also add nodes without any tags?
Yes, it does.
Uhh, so I'll skip --extra-attributes -- i didn't think about this before.
Also, was it ever considered to drop tags added as a real column from the hstore column? Now they end up in both, if the tag is present in default.style.
Yes we talked about thatand it's just a matter of coding it into osm2pgsql. The benefit from having the tags as columns is that value-lookups are much faster then they would be in the hstore, even with a gin-index on it. The benefit from having all tags in the hstore is easier statistical analysis, eg.
SELECT key, count(*) FROM (SELECT (each(h)).key FROM testhstore) AS stat GROUP BY key ORDER BY count DESC, key LIMIT 20;
gives you the top-20 used tags in osm. If some tags are only available as columns, it's not that easy to count them.
Peter