Re: Updates of SE-PostgreSQL 8.4devel patches (r1324)

KaiGai Kohei wrote:
> Gregory Stark wrote:
> > KaiGai Kohei <kaigai@kaigai.gr.jp> writes:
> > 
> >> I didn't replace the previous implementation blindly, I have a few
> >> reasons that the current one is better than previous one.
> >>
> >> For example, if an input handler has side-effects, what is happen in
> >> the following query?
> >>
> >>   SELECT 'valid_but_new_security_label'::regseclabel;
> >>
> >> It looks like a read-only query, but the input handler can insert a new
> >> tuple into pg_security. In addition, the newly inserted tuple may not
> >> be refered any more. It is a waste of spaces.
> > 
> > Ooh, and how would we know when to vacuum this label?
> 
> It is not necessary, because the number of security labels
> are assumed enough small.

Yep.   I agree doing something like regproc makes sense:
test=> \d pg_operator   Table "pg_catalog.pg_operator"    Column    |  Type   |
Modifiers--------------+---------+-----------oprname      | name    | not null oprnamespace | oid     | not null
oprowner    | oid     | not null oprkind      | "char"  | not null oprcanmerge  | boolean | not null oprcanhash   |
boolean| not null oprleft      | oid     | not null oprright     | oid     | not null oprresult    | oid     | not null
oprcom      | oid     | not null oprnegate    | oid     | not null
 
-->     oprcode      | regproc | not null
-->     oprrest      | regproc | not null
-->     oprjoin      | regproc | not null

but the auto-creation of pg_security rows does make this problematic. 
regproc works because it only supports pre-created pg_proc rows.

Can we support two data types, one for read-only and another for
possible creation?  That is not going to work for a query like
SELECT * FROM x WHERE col != 'valid_but_new_security_label'::regseclabel;

because the cast would fail if the pg_security row doesn't exist, but
the query itself perhaps might succeed and return rows.

Can we require joins to use pg_security directly?  I wish I could think
of some magic that indicated the pg_security row should be created.

--  Bruce Momjian  <bruce@momjian.us>        http://momjian.us EnterpriseDB
http://enterprisedb.com
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