[GRASS-dev] postgresql speed

[Vincent Bain]

Thank you for the links Moritz,

VB

Le mercredi 04 mars 2009 à 14:32 +0100, Moritz Lennert a écrit :
> On 03/03/09 22:17, Wouter Boasson wrote:
> > In reply to Vincent's remarks on database interfaces:
> > I don't know how the db.* modules are implemented, but I can't imagine that
> > they process the data themselves. 
> 
> No, they use the underlying engine of the backend. But connection is 
> costly. This is why scripts which had a loop calling [v.]db.* statements 
> in each run of the loop should be rewritten to collect SQL statements in 
> a temp file and then call db.execute once at the end. See [1] for the 
> example of v.rast.stats.
> 
> See also some comments of Radim in [2] under "Attributes".
> 
> Moritz
> 
> [1]http://trac.osgeo.org/grass/changeset/20358
> [2]http://freegis.org/cgi-bin/viewcvs.cgi/grass6/doc/vector/TODO?rev=HEAD&content-type=text/vnd.viewcvs-markup
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