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
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
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.