From: Tom Lane <tgl@sss.pgh.pa.us>
To: exclusion@gmail.com
cc: pgsql-bugs@lists.postgresql.org
Subject: Re: BUG #17877: Referencing a system column in a foreign key leads to
 incorrect memory access
In-reply-to: <17877-4bcc658e33df6de1@postgresql.org>
References: <17877-4bcc658e33df6de1@postgresql.org>
Comments: In-reply-to PG Bug reporting form <noreply@postgresql.org>
	message dated "Wed, 29 Mar 2023 14:00:01 -0000"
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Date: Wed, 29 Mar 2023 12:12:26 -0400
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PG Bug reporting form <noreply@postgresql.org> writes:
> The following query:
> CREATE TABLE pt(tid oid, id int, PRIMARY KEY(tid, id));
> CREATE TABLE ft(id int, FOREIGN KEY (tableoid, id) REFERENCES pt);
> produces a valgrind-detected error:

We should probably just disallow system columns as foreign keys.
There was a legitimate use-case for that with OID columns, but
no more.  I can't see a really good reason to use tableoid as a
foreign key, and none of the other system columns are stable
enough for this to be sane at all.  So it's hard to summon
interest in trying to remove bugs of this sort.

			regards, tom lane