Troubleshooting Functions
PostGIS_AddBBox
Add bounding box to the geometry.
Synopsis
geometry PostGIS_AddBBox(geometry geomA)
Description
Add bounding box to the geometry. This would make bounding box based queries faster, but will increase the size of the geometry.
Note
Bounding boxes are automatically added to geometries so in general this is not needed unless the generated bounding box somehow becomes corrupted or you have an old install that is lacking bounding boxes. Then you need to drop the old and re-add.
Examples
UPDATE sometable
SET geom = PostGIS_AddBBox(geom)
WHERE PostGIS_HasBBox(geom) = false;
See Also
PostGIS_DropBBox, PostGIS_HasBBox
PostGIS_DropBBox
Drop the bounding box cache from the geometry.
Synopsis
geometry PostGIS_DropBBox(geometry geomA)
Description
Drop the bounding box cache from the geometry. This reduces geometry size, but makes bounding-box based queries slower. It is also used to drop a corrupt bounding box. A tale-tell sign of a corrupt cached bounding box is when your ST_Intersects and other relation queries leave out geometries that rightfully should return true.
Note
Bounding boxes are automatically added to geometries and improve speed of queries so in general this is not needed unless the generated bounding box somehow becomes corrupted or you have an old install that is lacking bounding boxes. Then you need to drop the old and re-add. This kind of corruption has been observed in 8.3-8.3.6 series whereby cached bboxes were not always recalculated when a geometry changed and upgrading to a newer version without a dump reload will not correct already corrupted boxes. So one can manually correct using below and re-add the bbox or do a dump reload.
Examples
--This example drops bounding boxes where the cached box is not correct
--The force to ST_AsBinary before applying Box2D forces a recalculation of the box, and Box2D applied to the table geometry always
-- returns the cached bounding box.
UPDATE sometable
SET geom = PostGIS_DropBBox(geom)
WHERE Not (Box2D(ST_AsBinary(geom)) = Box2D(geom));
UPDATE sometable
SET geom = PostGIS_AddBBox(geom)
WHERE Not PostGIS_HasBBOX(geom);
See Also
PostGIS_AddBBox, PostGIS_HasBBox, Box2D
PostGIS_HasBBox
Returns TRUE if the bbox of this geometry is cached, FALSE otherwise.
Synopsis
boolean PostGIS_HasBBox(geometry geomA)
Description
Returns TRUE if the bbox of this geometry is cached, FALSE otherwise. Use PostGIS_AddBBox and PostGIS_DropBBox to control caching.
Examples
SELECT geom
FROM sometable WHERE PostGIS_HasBBox(geom) = false;