[postgis-users] Why so terribly slow?

[Sandro Santilli]

On Fri, Feb 10, 2012 at 09:13:59AM -0800, DavidRA wrote:
> Several test later, I'm sure that ST_MapAlgebraExpr() suits me perfectly.
> Besides it's very easy to use.
> 
> It's slower than using the equivalent function on a GIS tool like GRASS but
> I think that could be expected, isn't it? Though I'm curious about the
> reasons...

With great Power come great Slowness! :)

Seriously, the PostGIS version lets you use any kind of query, starting
up the PostGIS evaluator, which isn't really made to execute thousands
of statements at once.

--strk; 

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