The following bug has been logged online:

Bug reference: 2532
Logged by: Tiziano Tissino
Email address: t.tissino (AT) itaca (DOT) coopsoc.it
PostgreSQL version: 8.1.4
Operating system: Linux (Ubuntu Dapper)
Description: os.chdir call in plpython function doesn't work
Details:

I have a function like the following one:
CREATE OR REPLACE FUNCTION public.test() RETURNS int4 AS $BODY$
from os import chdir
chdir('/tmp')
test=plpy.execute('SELECT int_field FROM table1;')[0]['int_field']
return test
$BODY$ LANGUAGE 'plpythonu' VOLATILE;

when calling it, I get an error like this one:
db=# select test(); WARNING: plpython: in function test:
DETAIL: plpy.SPIError: Unknown error in PLy_spi_execute_query
ERROR: could not open relation 1663/16737/18906: No such file or directory
CONTEXT: SQL statement "SELECT int_field FROM table1;"

The same function, without the row "chdir('/tmp')", works fine.

I just upgraded to 8.1.4; with previous db version (8.0), that function
worked fine as well.

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"Tiziano Tissino" <t.tissino (AT) itaca (DOT) coopsoc.it> writes:
chdir is a great way to break your database. Don't do it.

Other things to avoid in plpythonu functions include: rm -rf,
kill -9 the postmaster, etc ...

regards, tom lane

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