[GRASS-dev] vector large file support

[Markus Metz]

Moritz Lennert wrote:
> On 11/02/09 12:54, Markus Metz wrote:
>> IMHO LFS support for vector libs is not necessarily good, currently. 
>> In order to manipulate large vectors, a very fast CPU, fast hard 
>> drives and lots of RAM is needed, or a lot of patience, because it 
>> can take days or weeks to run modules with large vectors as input. 
>
> Do you know which part of the modules takes most of the time ? I often 
> have the feeling that topology building and database access are the 
> two bottlenecks.
Me too. But I don't know what part exactly takes so long. The topology 
itself, the category index, or the spatial index? I have an eye on the 
spatial index, but that's gut feel. That would rather be an enhancement 
than a bug fix.
>
>> Maybe I should rather try to fix bugs than to add new features... 
>
> here are my two top candidates:
>
> - "Keep topology and spatial index in file instead of in memory" in 
> the vector ToDo. The fact that it is in memory makes simple vector 
> querying almost unusable when dealing with larger maps.
This could be regarded as a bug and is definitively an enhancement. The 
easiest of all your candidates, I guess.
>
> - http://trac.osgeo.org/grass/ticket/224
The dglib is still a mystery to me. I don't even know what modules use 
it. The other vector libs don't use it, that I'm relatively sure of.
>
> Just to keep you motivated ;-)
Thanks ;-)

Markus M