[postgis-users] Out of memory error with BOX3D

[Nicklas Avén]

Try St_Extent3D instead without st_collect. Then PostGIS can handle 1 point at a time and not all the 17 millions. So try:SELECT ST_Extent3D(punkte) FROM rohdaten WHERE id=109;
 ConvexHull is only working in 2D. It will keep the third dimension but not include it in the calculations (not 100% sure about that, but almost) HTH Nicklas

2010-10-20 Jan Saalbach wrote:

Hi all,
>an "out of memory error" occurs when I issue the following command:
>
>SELECT BOX3D(ST_COLLECT(punkte)) FROM rohdaten WHERE id=109;
>
>"punkte" is a GeometryColumn filled with POINT3D, 17 million for id=109. 
>The machine has 4GB of ram.
>
>I chose the box3d over the ConvexHull function because I thought it 
>would be much faster, and much less memory consuming. Apparently I was 
>wrong about memory consuming.
>
>What I do not get is why a computation as simple as "min x,y,z and max 
>x,y,z all at once" should consume that much memory. Can someone explain 
>to me what point I am missing?
>
>Issuing MIN(ST_X... MIN(ST_Y... commands one after another works fine 
>and is quite fast.
>
>Regards,
>Jan
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