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

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