[GRASS-dev] large vector and indices, speed up db

[Moritz Lennert]

On 26/02/09 18:37, Wouter Boasson wrote:
> In response to:
> 
>> Hello,
>> reading this thread, and being sometimes concerned with large vector
>> files (associated with big related tables), I wonder if it's worth
>> manually creating indexes (on cat field) : can it be a effective way to
>> speed up queries, or is the kink elsewhere, at the geometric level (data
>> handled by grass, not the linked DBMS) ?
>> Thank you,
>> Vincent
> 
> The problems with querying and topological operations must be at the
> geometric level (e.g. click an area to see the attributes using v.what, or
> cleaning operations).

Yes, querying the geometries is very slow currently because of the fact 
that the spatial and topological index is kept in memory and not on 
file, so every time you launch an interactive query, it has to rebuild 
it which is very slow on large vectors. See

http://josef.fsv.cvut.cz/WIKI/grass-osgeo/index.php/GRASS_7_ideas_collection#Radim.27s_TODO_list

Moritz