[Maposmatic-dev] Fwd: [OSM-dev] RAM requirement for osm2pgsql without slim?

[David MENTRE]

Hello,

There was recently a thread on osm-dev about the memory requirement in
non slim-mode for planet import.

It appears that the OSM tile server needs slim mode to do daily
import. So slim-mode is used daily and maintained.

Regards,
d.


---------- Forwarded message ----------
From: Jon Burgess <address@hidden>
Date: 2009/12/10
Subject: Re: [OSM-dev] RAM requirement for osm2pgsql without slim?
To: andrzej zaborowski <address@hidden>
Cc : dev Openstreetmap <address@hidden>


On Wed, 2009-12-09 at 12:48 +0100, andrzej zaborowski wrote:
> 2009/12/9 Peter Childs <address@hidden>:
> > I think its more like 16GB.
>
> I don't think that's still enough, Germany alone reaches the max of
> about 4.5GB RAM usage in non-slim mode and filesizes indicate it's
> only about 1/10th of the planet.

It does not scale linearly because the data structures in osm2pgsql are
optimised for densely populated IDs (as seen whem importing the full
panet). When you import an extract the IDs of the nodes and ways are
relatively sparse which makes the RAM usage less efficient.

I don't remember running a non-slim import of the full planet in the
past 12 months so I can't give any further clues about how much memory
it requires. The main tile server needs to use the slim mode in order to
support the diff updates.

       Jon



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