[postgis-users] dropping bboxes doesn't work ?!

Markus Schaber schabi at logix-tt.com
Mon Oct 17 02:11:27 PDT 2005

Hi, Ronald,

R. Müller wrote:

> i had to change the coordinate system for one table. after doing this,
> all geometries kept their old boxes in cache, so i tried to drop the
> bboxes  dropbbox(),

Why do you think you have to do this? Usually, PostGIS should keep the
bboxen in sync with the geometries vertex lists.

If you used setsrid() to update the geometries, the ordinate lists are
the same, and such are the cached bboxes.

If you used transform() to update the geometries, then the result
geometries should contain correct new bounding boxes. If not, you found
a severe bug in PostGIS, IMHO, and I'd kindly ask you to send us a test
case that we can use to reproduce and fix the bug.

> but obviously this operation failed since all
> geometries still kept their bbox in cache (i checked this with
> hasbbox()).

> the dropbbox()-operation returned a list with the 'right'
> bboxes, but no further comment.

Hmm, dropbbox() is a function that returns the argument geometry with
the cached bbox removed (if present before).

Can you send us the exact statement you used to update your table?

Did you commit your changes?


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