Hi,

Postgres 8.3 behaves different, if you access an unset
custom variable. Version 8.1 returned 'unset', while 8.3 fails:

plpython trigger:

CREATE OR REPLACE FUNCTION get_or_create_transaction_id() returns INT as $$
transaction_id=plpy.execute("SELECT current_setting('modwork.transaction_id') AS id")[0]['id']
if not transaction_id or transaction_id=='unset':
# First write, create transaction ID

ProgrammingError: unrecognized configuration parameter 'modwork.transaction_id'

PostgreSQL 8.1.4 on x86_64-unknown-linux-gnu, compiled by GCC gcc (GCC) 4.1.0 (SUSE Linux)
modwork_esg=# SHOW modwork.asfd;
modwork.asfd
--------------
unset


PostgreSQL 8.3beta3 on x86_64-unknown-linux-gnu, compiled by GCC gcc (GCC) 3.3.4 (pre 3.3.5 20040809)
modwork_esg=# SHOW modwork.asdf;
ERROR: unrecognized configuration parameter "modwork.asdf"


How can you check if a variable exists with 8.3?

BTW: current_setting() is not in the index:
http://www.postgresql.org/docs/8.3/s...bookindex.html

Hi,

There's the pg_settings table:

select setting from pg_catalog.pg_settings where name =
'modwork.transaction_id'

Or you could catch the syntax_error_or_access_rule_violation exception
raised by current_setting.

On Dec 14, 8:40 am, Thomas Guettler <h... (AT) tbz-pariv (DOT) de> wrote: