The following bug has been logged online:
Bug reference:      1504
Logged by:          Nicolas Rachinsky
Email address:      nr@rachinsky.de
PostgreSQL version: 7.4.7
Operating system:   FreeBSD 4.10
Description:        Wrong user is used for sequences through rules
Details:
As the user (nicolas) owning the database (webtempl) I execute:
DROP TABLE log CASCADE;
CREATE TABLE log(
        id BIGSERIAL PRIMARY KEY,
        msg TEXT NOT NULL DEFAULT ''
);
DROP TABLE log_insert CASCADE;
CREATE TABLE log_insert(
        msg TEXT NOT NULL DEFAULT ''
);
CREATE RULE log_ins AS ON INSERT TO log_insert
  DO INSTEAD
    INSERT INTO log (msg) VALUES (NEW.msg);
GRANT insert
ON log_insert
TO web;
----snip----
Now as user 'web' I try the following:
webtempl=> insert into log_insert (msg) VALUES ('foo');
ERROR:  permission denied for sequence log_id_seq
webtempl=>
It works after executing the following as the user owning the database:
GRANT update
ON log_id_seq
TO web;
---snip---
As user 'web':
webtempl=> insert into log_insert (msg) VALUES ('foo');
INSERT 1078083 1
webtempl=>
As I read
http://www.postgresql.org/docs/7.4/interactive/rules-privileges.html the
insert should
work without granting the update privilege.
                               version
----------------------------------------------------------------------
 PostgreSQL 7.4.7 on i386-portbld-freebsd4.10, compiled by GCC 2.95.4
Thanks,
Nicolas