[GRASS-user] v.buffer database error

[Falko Engel]

Am 09.05.2012 23:32, schrieb Markus Neteler:
> On Wed, May 9, 2012 at 5:29 PM, Falko Engel<falko.engel at web.de>  wrote:
>> Dear list,
>>
>> I had a strange behavior of v.buffer today:
>>
>> v.buffer input=mydata output=mydata_buf bufcolumn=my_buf_col
>>
>> results in an error:
>>
>> "DBMI-Postgres driver error:
>> Cannot select:
>> SELECT cat, my_buf_col FROM mydata"
>>
>>
>> However, if I copy the exact statement of the error message into
>>
>> echo "SELECT cat, my_buf_col FROM mydata" | db.select
>>
>> the result is fine!
> You could set this:
> g.gisenv set=DEBUG=3
>
> then relaunch the command to see if the more detailed output contains
> relevant pieces (to post here, not all please :-).
>
> To disable debug output, use
> g.gisenv set=DEBUG=0
>
> Markus
>
> ...
>> I'm using the following setup:
>> Opensuse 11.3, GRASS GIS 6.4.2
>>
>> My attribute tables are stored in a Postgres DB which is located on a
>> network server.
>> All other DB operations in GRASS are fine.
>>
>>
>> Falko
>>
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>> http://lists.osgeo.org/mailman/listinfo/grass-user

Dear Markus,

thanks for that hint! It helped finding the error.

I have to explain in a little more detail:
As I said my attribute tables are stored in a Postgres DB. I used to run 
the DB on localhost. But some weeks ago I moved it to a network drive 
for backup and accessibility reasons. Since I basically copied the old 
DB to the network drive the old DB still exists on localhost. So does 
the data set I used in the v.buffer example. Same DB name, same table name.
When I use db.select on this dataset I get the DB connection:

D3/3: db_driver_open_database() driver=pg database definition = 
'host=my_server,dbname=my_db'
D3/3: parse_conn : host=my_server,dbname=my_db
D3/3: token 0 : host=my_server
D3/3: token 1 : dbname=my_db
D3/3: host = my_server, port = (null), options = (null), tty = (null), 
dbname = my_db, user = (null), password = (null), schema = (null)


When I use v.buffer:

D3/3: db_driver_open_database() driver=pg database definition = 'my_db'
D3/3: parse_conn : my_db
D3/3: host = (null), port = (null), options = (null), tty = (null), 
dbname = my_db, user = (null), password = (null), schema = (null)

So far the problem is clear. v.buffer seems connect to the old DB on 
localhost.


But there is another aspect:

When I create a new dataset (using g.copy) with an a attribute table in 
the (correct) DB on the network drive v.buffer recognizes it! This new 
table doesn't exists on localhost.
Is there a way to pipe the debugging info to a file?

Falko