[OSM-dev] Multiple XAPI parameters...

Brett Henderson brett at bretth.com
Thu Jul 8 12:10:33 BST 2010


I've been wondering if hstore would be a good addition to the Osmosis
"simple" schema which does store junction information.  I wonder if a
combination of tags stored in a hstore column, and table data clustered by
GIST indexes on node.geom and way.linestring columns (ie. to organise the
data geographically) has the potential to reduce the amount of disk seeks
required for queries returning large numbers of rows.

On Thu, Jul 8, 2010 at 8:55 PM, Peter Körner <osm-lists at mazdermind.de>wrote:

>
>
> Am 08.07.2010 11:46, schrieb John Smith:
>
>  Does anyone know if pgsql hstore would facilitate something like XAPI
>> with similar performance, but allow multiple parameters?
>>
>
> The performance will be highly dependent on the number of queries but I
> think it will be in a similar range. One ting to remeber is, that osm2pgsql
> does *not* store junction information, just simple geometries. This makes it
> suitable for most display purposes but eg. not usable for routing. That's
> also the reason why you can't generate .osm format from osm2pgsql databases
> without the (possible slow) access to the _node, _way or _relation tables.
>
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