[postgis-devel] performance of force_collection()

[strk at refractions.net]

Seems good. Committed.
--strk;

On Fri, Feb 25, 2005 at 01:12:55AM -0800, Ron Mayer wrote:
> In a couple posts strk at refractions.net wrote:
> >On Fri, Feb 25, 2005 at 12:30:37AM -0800, Ron Mayer wrote:
> >> Is there a quick way of detecting the bounding box cache ..
> >This can be done - see TYPE_HASBBOX macro.
> 
> >>> Just another note. Your patch is not forcing a copy on DETOAST.
> >> ...I should have checked ... == COLLECTIONTYPE
> >Yes, that would be safe.
> 
> Thanks.   So if I understand right, this seems totally harmless
> and can avoid potentially significant overhead:
> 
> ======================================================================
> % diff -u lwgeom_functions_basic.c.bak  lwgeom_functions_basic.c
> --- lwgeom_functions_basic.c.bak	2005-02-25 01:04:35.049758952 -0800
> +++ lwgeom_functions_basic.c	2005-02-25 01:04:42.559617280 -0800
> @@ -1282,6 +1282,10 @@
>  	LWGEOM *lwgeoms[1];
>  	LWGEOM *lwgeom;
>  
> +       if ( TYPE_GETTYPE(geom->type) == COLLECTIONTYPE &&
> +            lwgeom_hasBBOX(geom->type) )
> +               PG_RETURN_POINTER(geom);
> +
>  	// deserialize into lwgeoms[0]
>  	lwgeom = lwgeom_deserialize(SERIALIZED_FORM(geom));
> 
> =====================================================================
> 
> and provides a way to let an unpatched mapserver avoid the overhead
> of excessively processing large geometries by letting me make the
> big geometries in my tables a 2D GEOMETRYCOLLECTION ?
> 
> If so, does that seem good for the real postgis?
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