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

[Graham Jones]

On 16 February 2012 16:25, Frederik Ramm <frederik at remote.org> wrote:

> Hi,
>
>
> On 02/16/2012 03:05 PM, Kay Drangmeister wrote:
>
>> Isn't there a hstore in the rendering-db?
>>
>
> No.
>
> 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?

The only time I tried to use hstore, the performance of the whole database
was dreadful (at least a factor of 5 slower, but I didn't do any proper
benchmarking - I just gave up and re-created it without hstore and the
problem went away).    It may have been that something went wrong with the
import that I did not notice, and it was not an hstore issue.

Using hstore would be really good given the fashion for generating new keys
with colons in them, but not with that reduction in performance, so I keep
having to re-import my database to add new keys.

<grumble> Why create a key generator:power_source rather than just use
power_source.  power_source is much more generic so you could re-cycle it
for things like district heating, but generator:power_source is only ever
going to be used for generating stations, and needs a new column in the
database. </grumble>.   I think I just prefer more generic, re-usable keys
rather than trying to invent a new one for each situation....

Regards


Graham.

-- 
Graham Jones
Hartlepool, UK.
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