RE: [postgis-users] An I/O error occured while sending to the backend

[Stefan Zweig]

hi rob,

you are right i could leave out the where part of the update query, but that would not change anything.
the_geom is in the update-query: buffer(simplify(the_geom,0.0063775005),0)

what i intend to do is to store the_geom with a lower resolution (the_geom_1) to accelerate reading of coordinates on smaller scales. the buffer(simplified_geometry,0) is intented to solve self-intersections which can occur while simplifiying a geometry and which cause other geometry functions (like intersection) to throw errors.

same querys work fine on other tables but not on this one.

i am wondering why postgre has to restart after i run that update query. that actually should not be, should it?

regards, stefan


> 
> First the ":" and your jdbc error means the postgres service has had to
> restart. The connection was terminated due to an error.
> 
> The questions that come to mind are the following:
> 
> What is the_geom? I see the_geom_1 but not the_geom.
> 
> Why are you buffering with a value of 0?
> 
> Why have a where clause at all for what you are doing? If you wanted to set
> all of the_geom_1 values just leave off the where clause.
> 
> 
> -----Original Message-----
> From: postgis-users-bounces at postgis.refractions.net
> [mailto:postgis-users-bounces at postgis.refractions.net] On Behalf Of Stefan
> Zweig
> Sent: Monday, August 13, 2007 8:46 AM
> To: PostGIS Users Discussion
> Subject: [postgis-users] An I/O error occured while sending to the backend
> 
> hi list,
> 
> i have a problem with running these querys:
> 
> SELECT
> AddGeometryColumn('public','_g2994','the_geom_1','4326','MULTIPOLYGON',2);
> 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
> 
> and nothing happens except that i get a message ': ' back from pgAdmin
> 
> if i try to run any query after that strange phenomenom i get a message,
> that there is not connection to the server and i have to refresh the
> connection to the server before i can run any other query again.
> 
> if i try the
> UPDATE _g2994 SET the_geom_1 = buffer(simplify(the_geom,0.0063775005),0)
> WHERE true with JDBC i get the following exception
> 
> org.postgresql.util.PSQLException: An I/O error occured while sending to the
> backend
>         at
> org.postgresql.core.v3.QueryExecutorImpl.execute(QueryExecutorImpl.java:214)
>         at
> org.postgresql.jdbc2.AbstractJdbc2Statement.execute(AbstractJdbc2Statement.j
> ava:452)
>         at
> org.postgresql.jdbc2.AbstractJdbc2Statement.executeWithFlags(AbstractJdbc2St
> atement.java:340)
>         at
> org.postgresql.jdbc2.AbstractJdbc2Statement.executeUpdate(AbstractJdbc2State
> ment.java:286)
> 
> does anybody know, what is wrong?
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