[OSM-talk] osm2pgsql hstore (was: Wind turbines no longer rendered on mapnik layer)

[Graham Jones]

On 16 February 2012 18:51, Frederik Ramm <frederik at remote.org> wrote:

> On 02/16/2012 07:25 PM, Graham Jones wrote:
>
>> This reminded me of a question I have been meaning to ask for quite a
>> while - is a database generated by osm2pgsql with an hstore expected to
>> perform similarly to one without?
>>
>
> I never ran one with hstore when I think of what this must mean for the
> database engine, and storage space, then I shudder and would not be
> surprised by the factor 5 you mentioned.


Thanks - I don't feel so bad about giving up so easily now!

If you want to add a new key but avoid re-importing the full database, you
> can add the key to osm2pgsql's style file, somehow generate an .osm file
> that contains only the objects that have this tag, wrap this .osm file into
> a "<osmChange><modify>...</**modify></osmChange>" instead of
> "<osm>...</osm>" and throw it at osm2pgsql in append mode.


That's a neat idea - will try that next time, thanks.


> People like keys that are understandable without context. Contrast this
> with a tag "width=2" - where you have no chance in knowing what it means
> without looking at the whole thing.


Yes - I think it is just a style difference - I am quite happy to interpret
it from context for the sake of having a smaller number of unique keys to
think about.

Cheers

Graham

-- 
Graham Jones
Hartlepool, UK.
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