[postgis-devel] Re: LW_GEOM questions

Markus Schaber schabios at logi-track.com
Mon Apr 19 06:03:58 PDT 2004


Hi, David,

On Wed, 14 Apr 2004 10:11:48 -0700
David Blasby <dblasby at refractions.net> wrote:

> ps.  I have indexing working right now.  I'm finding that it takes
> about 400ms to do 1000 sub-queries using LWGEOM, and the standard
> postgis geometries only takes 100ms.  Thats about 0.3ms per
> index-search slower. 
>   I think this is being causes because the bounding box of the search 
> lwgeom geometry has to be calculated (but its already avaiable in the 
> postgis geometry).

Could you run a benchmark on a larger dataset that involves harddisk
I/O?

And what about the proposal to include the bbox for large geometries?
(Maybe you could add the 4 floats = 16 bytes after the last geometry,
so the offsets for the other code doesn't change? It might even be
sensible to move the SRID to the end of the serialized format for this
reason)

Thanks,
markus

-- 
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