From: Peter Eisentraut <peter_e@gmx.net>
To: Michal Dobaczewski <mdobaczewski@cc.com.pl>
Subject: Re: libpq: usage of PQoidValue to obtain serial primary key after
	insert
Date: Thu, 22 Jul 2004 19:54:15 +0200
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Michal Dobaczewski wrote:
> I wonder: how will postgres behave if it happens to generate a
> repetitive oid for a table with such constraint?

You get a constraint violation error.

> I understand it will
> work it out somehow internally and get a different oid,

No.

> but I would
> like to be sure. It doesn't create a risk of inserts failing at
> random, does it?

Yes, it would (for certain definitions of "random").

> I also understand this theoretically limits the number of rows in a
> table to 2^32 whereas without such constraint there is no set limit -
> is that true? It's not a problem, we don't have such big tables so
> far but it would be interesting to know.

If you're concerned about that, you better go back to sequences and use 
bigserial columns.

-- 
Peter Eisentraut
http://developer.postgresql.org/~petere/