[OSM-dev] Is there a way to use simple schema without hstore

Frederik Ramm frederik at remote.org
Fri Nov 19 10:25:24 GMT 2010


Hi,

On 11/19/10 10:25, Andreas Kalsch wrote:
> I am sure there are some good uses for hstore, but as soon as you use
> it, you are waiting for something like a document-oriented database. I
> ask myself: Why do I need normal columns when there is hstore?

This is exactly what I was getting at. If you're driven by a desire for 
the pure, then you'd drop all the extra columns in the tables and have 
tags *only* in hstore. But it turns out that even if you go through the 
effort of adapting your mapnik style sheet to query the hstore columns, 
this doesn't perform well enough for proper tile rendering, so you 
re-add those columns that are used often...

>>> MongoDB, for example, unifies worlds by simply using JSON. I don't
>>> have to manually parse things I do not need to parse.

>> In turn, you will have a hard time getting the performance required
>> for a planet-wide application out of MongoDB.

> OK, can you explain further what the bottlenecks would be?

I've never touched MongoDB, I've just heard people enthusiastically 
adopt MongoDB for OSM and then growing very quiet. I think you were 
involved in that thread (back in July)?

But to go back to your original problem - I have a similar situation 
where a plugin has been written for Osmosis 0.33 which doesn't work with 
0.37 any more, and because I could not be bothered to fix that, I simply 
use two instances of Osmosis in a pipe - one 0.37 instance to handle the 
pbf and one 0.33 instance to interface with my plugin. Ugly but works.

Bye
Frederik




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