From: | Magnus Hagander <magnus(at)hagander(dot)net> |
---|---|
To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
Cc: | PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org> |
Subject: | Re: Duplicated oids between tables - problem or not? |
Date: | 2012-11-26 16:05:47 |
Message-ID: | CABUevEzGFAFR2bFm-PJ1+0YeYCXDir_HctV-N6K7sQZ-6tgaTg@mail.gmail.com |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-hackers |
On Mon, Nov 26, 2012 at 5:04 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> Magnus Hagander <magnus(at)hagander(dot)net> writes:
>> I noticed after a pg_upgrade on a system, that the same oid is used
>> both for a database and a user (repeated many times for different
>> combinations of databases and users). This is because pg_upgrade
>> doesn't preserve the database oid, and it reused the oid of the row in
>> pg_authid.
>
>> The reason I noticed this was that it confuses the hell out of
>> pgadmin. This is clearly a bug in a SQL query pgadmin uses, and I'm
>> going to go fix that.
>
>> But is this something that can cause us problems somewhere else in the
>> system? ISTM the same thing could happen after oid wraparound, but
>> that pg_upgrade makes it a lot more likely to happen. So I'm thinking
>> it shouldn't be a problem since the oid's are in different tables, but
>> are there any other parts of the system where this could cause an
>> actual problem?
>
> It should not. It's been understood for many years that uniqueness of
> OIDs is only guaranteed within individual catalogs (by means of their
> unique indexes on OID). That's why mechanisms like pg_depend and
> pg_description use catalog OID + object OID to identify objects.
That's what I figured. The problem with pgadmin is it joins to
pg_shdescription without restricting it on the catalog oid.
> We do insist that hand-assigned OIDs be globally unique, but that's just
> for maintainers' sanity not because the code depends on it.
Gotcha. Thanks!
--
Magnus Hagander
Me: http://www.hagander.net/
Work: http://www.redpill-linpro.com/
From | Date | Subject | |
---|---|---|---|
Next Message | Tom Lane | 2012-11-26 16:11:48 | Re: change in LOCK behavior |
Previous Message | David Fetter | 2012-11-26 16:05:21 | Re: Materialized views WIP patch |