[postgis-users] An I/O error occured while sending to the backend
mark.cave-ayland at ilande.co.uk
Wed Aug 15 14:48:27 PDT 2007
On Wed, 2007-08-15 at 15:45 +0200, Stefan Zweig wrote:
> hi mark, hi list,
> i have a problem with running these querys:
> ALTER TABLE _g2994 DROP CONSTRAINT enforce_geotype_the_geom_1;
> ALTER TABLE _g2994 ADD CONSTRAINT enforce_geotype_the_geom_1 CHECK
> (geometrytype(the_geom_1) = 'MULTIPOLYGON'::text OR geometrytype(the_geom_1)
> = 'POLYGON'::text OR the_geom_1 IS NULL);
> everthing is alright up to here...
> then i run
> UPDATE _g2994 SET the_geom_1 = buffer(simplify(the_geom,0.0063775005),0)
> WHERE true
> unfortunately i am not an expert in reading postgres' server.log but this what happens after the above querys where executed:
Which platform are you using - what is the output of "SELECT version()"
and "SELECT postgis_full_version()"? If you Google for PostgreSQL/Signal
11 then it can be caused by bad hardware, a process exceeding its ulimit
threshold or a bug in the backend (perhaps GEOS/PostGIS).
In some cases, the problem can be caused by a single geometry within a
table - perhaps the buffer() and/or simplify() calculations are causing
in error? In this case you could try and identify the geometry in
question doing something like:
CREATE TABLE test AS SELECT gid,
buffer(simplify(the_geom,0.0063775005),0) FROM _g2994;
If this crashes, then the first geometry that isn't in the test table is
causing it to crash, i.e. the geometry with the next highest gid.
ILande - Open Source Consultancy
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